methods and issues of studying the brain in psychology

METHODS AND ISSUES OF STUDYING THE BRAIN IN PSYCHOLOGY Kevin Brewer ISBN: 978-1-904542-48-3

Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3 2

This document is produced under two principles: 1. All work is sourced to the original authors. The images are all available in the public domain (most from http://commons.wikimedia.org/wiki/Main_Page ). You are free to use this document, but, please, quote the s ource (Kevin Brewer 2009) and do not claim it as you own work. This work is licensed under the Creative Commons Attribution (by) 3.0 License. To view a copy of thi s license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ or send a letter to Creative Commons, 171 2nd Street, Suite 300, San Francisco, California, 94105 , USA. 2. Details of the author are included so that the l evel of expertise of the writer can be assessed. This co mpares to documents which are not named and it is not poss ible to tell if the writer has any knowledge about their subject. Kevin Brewer BSocSc, MSc An independent academic psychologist, based in Engl and, who has written extensively on different areas of psychology with an emphasis on the critical stance towards traditional ideas. Orsett Psychological Services, PO Box 179, Grays, Essex RM16 3EW UK [email protected] ( http://kmbpsychology.jottit.com ) or ( http://psyman.weebly.com )


CONTENTS Page N umber 1. Introduction 5 2. Studying the Brain Outside the Body 7 2.1. Tissue or cell culture 7 2.2. Post mortems 9 3. Studying Non-Human Animals 1 2 3.1. Olds and Milner (1954) 1 3 3.2. Key arguments for studying non-human animals to understand humans 1 4 3.3. Key arguments against studying non-human animals to understand humans 1 5 4. Intervention Techniques 1 8 4.1. Destruction of brain tissue 1 8 4.1.1. Psychosurgery 1 9 4.1.2. Brain lesions - example with animals: Lashley (1931) 2 1 4.2. Split brain patients 2 4 4.3. Artificial stimulation 2 8 4.3.1. Wilder Penfield 2 9 4.3.2.Studying temporal aspects of perception 3 4 5. Naturally Occurring Brain Damage 3 7 5.1. Brain injury/damage from birth 3 7 5.2. Acquired brain injury/damage 3 7 5.2.1. Phineas Gage 3 8 5.3. Brain injury/damage through illness 4 1 5.3.1. Clive Wearing 4 4 6. Recording Electrical Activity 4 7 6.1. Electroencephalogram 4 7 6.2. Evoked potentials or


event-related potentials 4 7 6.3. Magnetoencephalography 4 8 6.4. Single unit recording 4 8 7. Computer Tomography/Neuorimaging 5 0 7.1. Computerised axial tomography 5 2 7.2. Positron emission tomography 5 3 7.2.1 Single-photon emission computerised tomography 5 5 7.2.2. Hippocampus and London taxi drivers 5 5 7.3. Nuclear magnetic resonance imaging 5 8 7.4. Magnetic resonance spectroscopy 5 9 7.5. Functional magnetic resonance imaging 5 9 7.6. Ethical issues and neurimaging 6 0 8. New and Miscellaneous Techniques 6 5 9. Issues and Debates 6 6 9.1. Mind-brain relationship 6 6 9.2. Conscious and not conscious 6 9 10. References 7 5 11. Appendix 8 3


1. INTRODUCTION The brain has been studied in psychology using a number of different methods over time and currently : i) Studied in detail outside the body as with post-mortem brains, and in tissue cultures; ii) Through studying the brains of non-human animals; iii) Intervention and artificial stimulation techniques that deliberately damages or alter the b rain in some way; iv) Studying case studies of naturally occurri ng brain injury and damage; v) Recording of electrical activity as with electroencephalography (EEG); vi) Modern technological methods of computer tomography and neuroimaging - computerised axial tomography (CAT), positron emission tomography (PET ), single-photon emission tomography (SPECT), magnatic resonance imaging (MRI), functional magnetic imagin g (fMRI), and magnetic resonance spectroscopy (MRS); There are many different ways used to study th e brain, but they can be classified as: � Invasive/non-invasive - whether the researcher goes

inside the skull (table 1); � Intervening with the brain's normal functioning or not

(table 2); � Studying the active or the static live brain, or th e

dead brain (table 3); � Studying the structure or function of the brain (ta ble

4).

Table 1 - Examples of invasive and non-invasive met hods of studying the brain.

INVASIVE NON-INVASIVE

� Animal studies � Artificial stimulation � Destruction � Post-mortems

� Patients with brain damage � Tissue culture � Transcranial Magnetic

Stimulation (TMS) � Tomography


Table 2 - Methods of studying the brain involving intervention or not.

Table 3 - Methods studying the active or static liv e brain, and the dead brain.

Table 4 - Methods studying the structure and functi on of the brain.

ACTIVE LIVE BRAIN STATIC LIVE BRAIN DEAD BRAIN

� Animal studies � Artificial stimulation � Destruction � Electrical recording � fMRI � Patients with brain

damage � PET scans � MEG � TMS

� CAT scans � MRI

� Post-mortems

STRUCTURE FUNCTION BOTH

� CAT scans � MRI

� Artificial stimulation � Destruction � Electrical recording � fMRI � Patients with brain damage � PET scans � MEG � Tissue culture � TMS

� Animal studies � Post-mortems

INTERVENTION NON-INTERVENTION

� Animal studies � Artificial stimulation � Destruction � TMS

� Patients with brain damage � Post-mortems � Tissue culture � Tomography


2. STUDYING THE BRAIN OUTSIDE THE BODY One way to study the brain, and overcome the p roblem of accessibility, is outside the body. This is done with tissue or cell culture (live) and post-mortems (dea d tissue). 2.1. TISSUE OR CELL CULTURE A small amount of brain tissues or cells can b e kept alive outside the body as tissue or cell cultures. These are known as "in vitro" (outside the body) compared to "in vivo" (inside the body)(Whatson 2004). The cell s or tissues continue to grow in nutrients (table 5). Some cultures can continue to grow as long as required ("immortalized cell lines") while others h ave a limited lifespan (Whatson 2004). A typical experiment involves stimulating a particular cell, like a Purkinje cell from the cere bellum (figure 1), in different ways to see the response (Whatson 2004). STRENGTHS 1. Ideal for the study of specific cells and their physiology. 2. The cells are alive and so have advantages over post-mortem tissue, like responsiveness to stimuli. 3. No ethical concerns as with live participants. 4. Overcomes problems of studying these cells "in v ivo". WEAKNESSES 1. The study of individual cells without the normal interactions in the brain. It is like studying a city by concentrat ing on one person only. 2. Isolated cells behave differently in nutrients t han in situ (inside the brain) like maintaining their usual str ucture. 3. Very reductionist - trying to understand the com plexity of the whole brain from individual cells. 4. How are the cells and tissues obtained? Probably by use of an invasive technique like brain surgery. Table 5 - Strengths and weaknesses of using tissue or cell culture to study the brain.


Purkinje cells - green (Source: Sbrander; in public domain)

Figure 1 - Mouse cerebellum seen with laser scannin g microscope. 2.2. POST-MORTEMS Historically, this was the first method used t o study the brain. The brain of the dead person (or a nimal) is examined. It "remains the gold standard" method because of the ability to study genetic, molecular, cellular, and neurochemical aspects (Deep-Soboslay et al 2005). This gives it advantage over the other metho ds of study of non-human animals, or of live humans in neuroimaging studies (table 6). The brain can be sliced to reveal the internal parts as well as evidence of abnormalities in size or sha pe, and tumours, for example.


There is a routine 48-hour interval between de ath and the post-mortem (Harrison 1996). STRENGTHS 1. Overcomes limitations of using other methods wit h animals to study human behaviour. 2. More detailed examination of genetic, molecular, cellular, and neurochemical aspects of the brain than neuroimagin g of live participants. 3. Used to study brain structure as well as biochem istry. 4. Gains details that non-invasive studies cannot, like the ability to study individual parts of the brain under a micr oscope. 5. No concerns about the ethics of treatment as wit h live participants. 6. Non-intervention method which can be used with h umans and non-human animals. 7. Able to investigate the internal parts of the br ain. 8. Complex techniques, like immunohistochemistry, a id the understanding of brain chemistry. WEAKNESSES 1. Death may cause changes for the brain. 2. Confounding variables include: � Peri-mortem (ie: before death); eg: fever as cause of death; � Post-mortem; eg: method of storing body after death ; � Miscellaneous; eg: age of individual, smoker, drug addict. 3. Not possible to establish cause and effect relat ionships as in experiments with live participants. 4. Problems of retrospective diagnosis of problems after death. 5. Reductionist - studies individual parts, even ce lls, and not the whole brain. 6. Dead tissue decays and dries out quickly even wi th a speedy preservation process. 7. The brain has to be preserved by chemicals, like formalin. Brain slices are often stained by Golgi stain or horserad ish peroxidase to aid microscopy (Whatson 2004). These processes alte r the brain. 8. Methods using live human participants allows the m to talk about their sensations and thoughts while the brain is be ing studied. This is not possible with post-mortems or studies with n on-human animals. Table 6 - Strengths and weaknesses of studying the brain using post-mortems.


The best known examples of discoveries about t he brain using the post-mortem method with human brain s relate to Broca's and Wernicke's areas (figure 2). In 1861, Paul Broca (figure A appendix) reported the c ase of "Tan" (box 1). This was a man who could only say "t an-tan", but had a fuller understanding of speech (kno wn now as expressive aphasia). The post-mortem of "Tan" fo und damage in the left frontal lobe in a region now kno wn as Broca's area. Wernicke's area in the left temporal lobe is n amed after Carl Wernicke who studied stroke patients abl e to speak, but who had problems with language comprehen sion (known now as receptive aphasia).

(Source: US Federal Government; in public domain; http://www.nidcd.nih.gov/health/voice/aphasia.asp )

Figure 2 - Broca's and Wernicke's areas. Complex techniques today using electron micros copy allow researcher to understand the biochemistry of the brain (Whatson 2004): � Immunohistochemistry - washing brain slices in cert ain

fluids highlights antibodies, for example, present. Antibodies are reactions to attacks on the immune system and are taken as evidence of diseases;

� Autoradiography - radioactive substances can be use d to

show what substances are within the brain tissue; � In situ hybridization - this can locate proteins in the

brain tissue.


Box 1 - Details of post-mortem of "Tan" by Paul Bro ca (1861). In terms of the biochemistry of the human brai n, Owen et al's (1978) study of the brains of sufferer s from schizophrenia after death found an excess of the receptors for the neurotransmitter, dopamine, in th e limbic system. Specifically, more D2 receptors than in the brains of non-schizophrenic individuals.

"Tan" was 51 years old when he died on 17th April, 1861 at Bicetre hospital in France, and he had lost his speech before 21 years old (when first seen at the hospita l). He was also paralysed on the right side. His intelligence was affected to "a great degree" " but he maintained certainly more of it than was needed for talking". He answered some questions with gestures, and others not at all (even when the answer was obvious ). At the autopsy, the dura mater was found to be thic kened and vascularised, covered on the inside with a thick ps eudo-membranous layer; the pia mater thick, opaque, and adherent to the anterior lobes particularly the left lobe. The frontal lobe of the left hemisphere was soft over a great part of its extent ; the convolutions of the orbital region, although atrophied, preserve d their shape; most of the other frontal convolutions were entirel y destroyed. The result of this destruction of the cerebral substanc e was a large cavity, capable of holding a chicken egg, and fille d with serous fluid. The softness had spread up to the ascending fold of the parietal lobe, and down to the marginal fold of the temporal-sphenoidal lobe; finally, in the depths, [it spread to] the region of the insula and the extraventricular nucleus of the striate body; it was the lesion of this last organ which was respons ible for the paralysis of the movement of the two limbs of the right side. However, it suffices to cast a glance at this paper to recall that the principal home and the original seat of the sof tness, is the middle part of the frontal lobe of the left hemisph ere; it is there than one find the most extensive lesions -- the mos t advanced and the oldest. The softness progressed very slowly to the adjoining parts and one can regard it as certain that it was there for a very long period. [p. 238] during which the illness did not a ffect the convolutions of the frontal lobe. This period proba bly corresponds to the eleven years that preceded the paralysis of the right arm, and during which the patient had maintained his intelli gence, having lost nothing other than speech. All this permits, however, the belief that, in the present case, the lesion of the frontal lobe was the cause of the los s of speech (Broca 1861 pp237-8; translated by Christopher. D. Green 2 003; http://psychclassics.yorku.ca/index.htm ).


3. STUDYING NON-HUMAN ANIMALS Non-human animals can be studied in ways simil ar to humans or in cases where it is not possible to stud y humans. Often non-human animals are used where dire ct intervention is required. Table 7 compares the meth ods used to study the brain of human and non-human anim als. METHOD SAME DIFFERENT Post-mortems yes Destruction Larger areas than wit h humans Artificial Greater risks than wi th humans stimulation and less concern abou t side effects, including death Table 7 - Methods used to study the brain of human and non-human animals. Home Office (2005) data showed that in all lic ensed scientific experiments in 2005, 20 542 animals had "interference with brain" and 13 978 "injection int o brain". The most common animals used were rats and mice. These figures relate to all scientific research, no t just psychology nor only to study the brain. There are both strengths and weaknesses in stu dying non-human animals to understand the human brain (ta ble 8). STRENGTHS 1. Non-human animals can be used in ways unacceptab le with humans. 2. A "shared biological heritage" between human and non-human animals. 3. The whole process of development can be observed in animals with short lifespans. 4. Greater control over variables by keeping animal s in standard laboratory cages. 5. Gives ideas for research with humans. 6. Benefits from research findings for humans. WEAKNESSES 1. The physiology of non-human animals is not exact ly the same as humans. 2. The morality of using animals in experiments.


3. The ethics of inflicting pain and suffering upon animals in experiments. 4. Human and non-human animals are different in a n umber of ways including the use of language, and flexibility in l earning. 5. Animals are kept and studied in the artificial e nvironment of the laboratory. 6. There are alternative methods available which in volve studying humans to understand the human brain. Table 8 - Strengths and weaknesses of studying non- human animals for understanding the human brain in psycho logy. 3.1. OLDS AND MILNER (1954) In a classic experiment, Olds and Milner (1954 ) placed electrodes in the brains of fifteen male hoo ded rats in order to stimulate particular areas of the brain. Under anaesthesia, the 0.010 inch diameter electrod es were implanted in the brain and attached to a block cemented on the skull and wires through which the m inute electrical signals (0.5-5 volts) were sent. Straigh t after testing, which occurred three days after the operation, the animals were killed ("sacrificed") i n order to perform a post-mortem study of the brain. Different areas of the brain were implanted in order to see how the rats responded to stimulation of the areas. The research concentrated on, what was later called, the "reward" or "pleasure centre" (Olds 195 6) of the brain. The rats would press the lever frequentl y to receive stimulation to electrodes in that area of t he brain (in forebrain). For example, "rat no.32" pressed the lever ove r 3000 times in twelve hours, and "rat no.34" 75000 times in the same period. This is known as electrical self-stimu lation of the brain" (ESB). Table 9 lists the main strengths and weaknesse s of the research by Olds and Milner (1954). STRENGTHS 1. Controlled environment of the experiment includi ng implanting of electrodes and testing. 2. Both overt behaviour was observed (lever pressin g) and the effect upon the brain (post-mortem study). 3. Able to isolate areas of the brain involved in f eelings of "pleasure" and "reward". 4. Animals not deprived of food and water during th e experiment.


WEAKNESSES 1. The effects of the operation upon the rats' brai n (ie: damage caused other than implanting the electrodes). 2. The rats' lives ended immediately after testing for post-mortem study. The ethics and morality of such behaviour by the researchers. 3. Not studying "natural" behaviour as rats inhibit ed by, for example, wires attached to skull. 4. A small number of rats were used, and different areas of the brain tested (eg: 4 rats had electrodes in septal area, o ne rat in hippocampus). Table 9 - Strengths and weaknesses of experiment by Olds and Milner (1954). 3.2. KEY ARGUMENTS FOR STUDYING NON-HUMAN ANIMALS TO UNDERSTAND HUMANS 1. It is possible to use invasive techniques that w ould be unacceptable with humans. This includes the destruction of larger areas of the brain, and great er levels of artificial stimulation without concern fo r the side effects or consequences. In other words, it is not seen as an issue if the animal dies, which is not possible with human participants. 2. In terms of physiology, non-human and human anim als are the same. The biology of the brain is the same with common evolutionary origins, even if the human brai n has developed further than other mammals. This is calle d the "shared biological heritage". For example, dopamine in the substantia nigra area of the brain controls mov ement in the same way in rats and humans (Whatson 2004). There are also common ailments and diseases. F or example, narcolepsy (sleep disorder) occurs in both humans and certain breeds of dogs (Whatson 2004). 3. Non-human animals with short lifespans allow researchers to study the whole proces of developmen t and several generations. Such animals can be kept in controlled environments which limit outside influen ces and confounding variables. Thus the mouse is seen as an ideal candidate t o study with its short lifespan, rapid maturation, mu ltiple offspring, documented genetics, and ease of housing (Whatson 2004). But Baldwin and Berkoff (2007) reported eviden ce that standard laboratory conditions used with mice and


rats caused stress, enough to affect the animals' physiology, and this produced a major confounding variable. 3.3. KEY ARGUMENTS AGAINST STUDYING NON-HUMAN ANIMALS TO UNDERSTAND HUMANS 1. Non-human animals are not exactly the same as hu mans in terms of physiology. For example, comparison of visual processing in the brain of rhesus monkeys and human s found similarities, but also key differences in "th e higher-order areas of the association cortex" (Orba n et al 2004). The study of non-human animals to aid the understanding of humans is based upon the assumptio n that similar physiology and genes do the same things in different species. In the case of genes, similar ge nes in different species are said to be orthologous (Liao and Zhang 2008). But if the same gene had different fun ctions in two species, this would challenge research using animals to understand human genetics. Liao and Zhang (2008) found 1450 orthologous g enes between mice and humans, and then concentrated upon 120 human genes. Genes were rated as essential ("loss o f function renders the fitness of the organism zero") or non-essential. In practice, "essential" means the organism dies before puberty, or if survives into adulthood is infertile. Twenty-seven (22.5%) of the human genes rated as essential in humans were non-essenti al in the mouse. This study focused upon genes for diseas es. So it could be that results from animal studie s are not applicable to humans because many of the appare nt anomalies in animal experiments merely reflect the unique biology of the species being studied (Barnard and K aufman 1997). In another example, a vaccine for Alzheimer's disease ("AN-1972") worked on genetically modified mice, but there was evidence of brain inflammation in hum an clinical trials (Roundabout 2002). 2. The ethical and moral question of whether it is right to use non-human animals in this way, particularly when pain and suffering are involved. This issue is addressed by legal restrictions on the use of animals in experiments, like the Animals (Scientific Procedures) Act 1986 in Britain. Any experiment using a non-human animal requires a lice nce from the Home Office.


In a report for the British Union for the Abol ition of Vivisection (BUAV), Langley (2006) listed the ty pes of experiments used with primates for "fundamental research". This is "knowledge-driven studies with n o foreseen medical relevance, to basic medical resear ch that might, in time, contribute to new ways of prev enting or treating human disease" (p84). This included bra in lesions, electrodes and probes to study vision, tas te, hearing and the brain of marmosets and macaques. Th e reality of these experiments is suffering for the a nimals (box 2).

Box 2 - Examples of the reality of suffering of experiments on vision, hearing and taste with prima tes. Concern generally over experiments with non-hu man animals has led to the "Three Rs" campaign to Repla ce, Reduce and Refine such experiments (Langley et al 2 007). For example, the replacement of animal lesioning experiments, where an area of the brain is surgical ly damaged, by Transcranial Magnetic Stimulation (TMS) with human volunteers, where a magnetic field temporaril y and safely disrupts part of the brain (table 10).

Vision research and similar studies on primates inv ariably cause suffering, sometimes classed as substantial. For el ectrophysiology, surgery typically, involves removing an area of sku ll to expose the brain, and cementing a metal ring over the area. To the ring is attached an electrode positioner and electrodes. Me tal tubes are cemented onto the skull for restraining the monkey by the head during recording and stimulating sessions. Scleral search coils may be implanted in the eye to monitor eye movements. Animals are sometimes deprived of food or water for many hours prior to the experiments, to motivate them to perform vis ual tasks. During recording or stimulating sessions, which can last f or several hours a day, animals are usually conscious and restrained i n chairs by the metal fixtures cemented to the skull. To avoid othe r animals tampering with the implants, in some laboratories m onkeys are kept in solitary confinement for the duration of experiment s which can last for months or years. Some monkeys are used and re-used in similar experi ments for very long periods of time. In the late 1980s, a monkey u sed at Oxford University in taste research had had electro de implants in the brain for five years, during which four experiments were conducted. At the Catholic University of Leuven in Belgium, some monkeys had been kept instrumented in single caging for two years, while being used and re-used in vision research. In tract-tracing studies, monkeys are injected with tracers into the eye, or elsewhere along the visual pathways. They a re later killed for post-mortem analysis. Sometimes specific areas of the brain are ablated, or fibrous tracts severed, to discover the roles of these areas in vision (Langley 2006 p86).


STRENGTHS � Non-invasive. � Temporary "virtual lesion". � Use of humans to study humans. � Repeated measures design experiments possible (ie: same

individuals tested with and without TMS). � Avoids problems of brain surgery, including operati on itself, side

effects, and functional re-organisation of the brai n afterwards. WEAKNESSES � Not as precise as surgery in inhibiting certain are as of the

brain. � Only short-term: not able to show permanent and lon g-term effects

of damage to particular areas of the brain. Table 10 - Strengths and weaknesses of the use of T MS with humans as alternative to animal lesioning experiments. 3. There are differences between human and non-huma n animals in terms of the use of language, and the flexibility of humans to learn. "Lack of linguistic complexity.. restricts ani mals' ability to solve problems by the manipulation of sy mbols, to reflect on the past and future.." and "..it may be only a human being who monitors his own monitoring, seeing his behaviour as more or less efficiently go al-directed.." (Hinde 1987 p26).


4. INTERVENTION TECHNIQUES These techniques involve interfering with the brain in some way either through destruction or artificia l stimulation of a particular area. 4.1. DESTRUCTION OF BRAIN TISSUE Brain tissue in a particular region of the bra in may be deliberately destroyed or damaged to see the eff ect upon the behaviour of the human or non-human animal . For ethical reasons, it is more often with non-human an imals. There are different techniques used to destroy the brain tissue: i) Ablation This is the surgical removal of a small area o f brain. This can be done as an experimental investig ation as well as medical intervention for malfunctioning brain tissue or to alleviate the symptoms of a disorder l ike severe epilepsy. Blasdel (1992) reported work with a technique that involved surgically removing part of the skull of a monkey and replacing it with a glass window. An opt ical dye is injected in the brain and it responded by co lour change to an electrical field (ie: brain activity). When applied to the visual cortex, it was possible to establish which cells responded to left or right ey e stimuli. This technique is most effective when studying the surface of the brain (Eysenck and Flanagan 2001). Chemical ablation is also used in a technique known as excitotoxocity (Whatson 2004). Cells are, in eff ect, poisoned, and destroyed that way. ii) Lesion This involves cutting part of the brain. The procedure with a lesion is known as "-ecto my", and with removal, it is an "-otomy" (Whatson 2004). For example, historically, psychosurgery with individua ls with mental illness has focused on the pre-frontal cortex, and tissue connecting the frontal lobes to other areas of the brain. Pre-frontal lobotomy removes th e cutting tissue and pre-frontal leucotomy cuts it. Ablations and lesions had been performed with knives, lasers that burn away the tissue, more rece ntly,


or with a strong electric current that does the sam e. 4.1.1. Psychosurgery Modern psychosurgery was began by Egas Moniz i n 1936 who developed the technique of prefrontal leucotomy . However, "history has not treated the man or his invention kindly. Scientists and lay people alike l ook back upon the age of psychosurgery with critical ey es, deploring the procedure that turned men and women i nto ‘mental invalids’ or ‘drooling zombies’" (Tierney 2 000 p22). Moniz (birth name: Antonio Caetano de Abreu Fr eire) was a Portuguese neurologist born in 1874. His tech nique to cut part of the frontal lobes in order to "cure" mental illness was based on the (incorrect) assumpt ion that pathological circuits in the brain has become fixed (causing the mental illness), and surgery would eli minate the consequent abnormal thinking (Tierney 2000). Psychosurgery had been tried in the late ninet eenth century to treat neurological symptoms of syphilis. But this involved making holes in the skull to drain fl uid from the brain which was causing the insanity. Or p arts of the cortex were removed in schizophrenics to red uce aggression. Both techniques "were greeted with much criticism from the medical communities in Britain a nd and Europe" (Tierney 2000). Moniz's aim was to destroy connections between the prefrontal cortex and other brain regions. The earl y operations did this by injecting a small amount of "absolute alcohol" which killed cells, while the la ter operations used a "leucotome" 1. This was a specially designed cutting device (Tierney 2000). The first series of operations (Moniz 1936) in cluded twenty individuals with anxiety, depression, and schizophrenia. The first patient (a 63 year-old wom an) was pronounced "cured" of her paranoia and hallucin ations two months after the operation. Of the twenty, Moni z rated seven as cured, seven as improved, and six unchanged after the operation. Tierney (2000) noted the criticisms of Moniz's report from today's point of view: � Inadequate follow-up times (eg: days or weeks only) ; � Absence of a control group - Not standard practice in

1 Picture at http://www.medicine.manchester.ac.uk/images/museum/full/warlinghamparkleucotome.jpg.


the 1930s; � Superficial evaluation of patients (ie: no standard ised

testing of abilities); � Subjective evaluation of patients performed by hims elf

or "asylum physicians who were aware of the aims of the procedure" (p31). Blind assessment of patients also not standard procedure in 1930s;

� Ignoring negative changes in personality, emotions, and behaviour after the operation.

Moniz felt that the "facts speak for themselve s: These were hospital patients who were well studied and well followed. The recoveries have been maintained. I cannot believe that the recover ies can be explained upon simple coincidence. Prefrontal leucotomy is a simple operation, a lways safe, which may prove to be an effective surg ical treatment in certain cases of mental disorder (Moniz 1937 p1385 quoted in Tierney 2000 p31) . The problem of the time was that the alternati ves in terms of treatments for severe mental illness were limited to techniques like insulin coma and electroconvulsive shock. Anything that seemed to wo rk would be well received. Prefrontal leucotomies were quickly popularise d in many countries, and, especially in the USA, were pr omoted by Walter Freeman (eg: Freeman and Watts 1950). "Freeman’s energetic support for psychosurgery, the sheer number of operations he performed, and his developm ent of the infamous transorbital lobotomy (in which fronta l white matter was destroyed via an ice pick-like instrument pushed into the brain though the bone be hind the eyeball) are legendary..." (Tierney 2000 p31). The attitude of the time towards mental illnes s can be seen: Freeman repeatedly argued, however, that the symptoms of mental illness were more distress ing to the patients and their families than the symptoms incurred by the surgery, and he poin ted out that even if patients were not completely cured, the surgery often made them easier to care fo r and able to live at home (Tierney 2000 p32). Moniz began by cutting the brain areas, while subsequent method of lobotomies destroyed brain are as. For example, in the USA, less than 300 lobotomies w ere performed in 1945, but this increased to nearly 500 0 in 1951 (total of 20 000 between 1945-51), and 10 000


individuals had some form of psychosurgery between 1942-54 in England and Wales (Tierney 2000). "Thus Moniz ’s innovative, ‘audacious’ procedure prematurely shed its status as an experimental, very cautiously applied operation, and entered a period of indiscriminate u se and unchecked expansion" (Tierney 2000 p33). As Moniz received the Nobel Prize in Physiolog y or Medicine in 1949 for his work, voices of dissent fo r psychosurgery were being raised. An article in the "New England Journal of Medicine" (Hoffman 1949) describ ed the post-operative patients as, among other things, "du ll, apathetic, listless, without drive or initiative.." (p233; quoted in Tierney 2000 p33). "In retrospect, it seems obvious that the blin d, grossly imprecise techniques employed by lobotomist s could only impair the intricate functioning of the human frontal lobes, creating additional emotional and behavioural impairments rather than curing the init ial disease" (Tierney 2000 p33). The 1950s and 1960s saw the development of psychotropic drugs for mental illness, and psychosu rgery declined in popularity, though it is still used tod ay. The "idea that brain surgery may help the mentally ill has never completely died, but instead returned to its point of origin, becoming once again a technique us ed very sparingly on patients with severe, chronic, treatment-refractory disorders" (Tierney 2000 p34). 4.1.2. Brain Lesions - Example with Animals: Lashley (1931) Lashley was interested in the localisation of brain function (ie: different parts of the brain have dif ferent functions). He began critical of the view from the nineteenth century that "because the mind is a unit the brain must also act as a unit" (p245). This is the view that the brain works as a whole for each ability. Lashley studied rats using apparatus of the da y like a choice of cardboard doors with visual patterns an d rats learn which pattern represents food, and mazes. The n an area of cortex was damaged to see the effect on vis ual perception and memory. It was found that damage to small areas of the occipital (visual) cortex affected vision the same as destruction of the whole cortex. This showed that specific functions were localised to particular are as. In some cases, the rats' brains were damaged b efore learning the maze. These animals were slower to lea rn than healthy rats, and it did not matter which part of the cortex was destroyed: "The degree of retardatio n


seems proportionate to the amount of tissue destroy ed, irrespective of the locus of injury" (p249). For ex ample, destruction of any 10% of the cortex produced over one hundred errors during learning, 20% over two hundre d, and 80% over 1000 errors. There was a correlation of 0. 84 between amount of cortex destroyed and number of er rors during maze learning. If the rats learned the maze, and then underwe nt surgery, the memory loss was related again to exten t of damage not location. So "every part of the cortex p lays a part in learning and in retention" (p250). This has been called the equipotentiality or mass action of neura l tissue. Lashley's work had shown the paradox of the br ain that certain functions are clearly localised to particular brain areas, whereas other functions are not and involve the whole cortex. Lashley defended the use of rats in his experi ments with the following arguments: � "simplicity of the animal's behaviour, its steadine ss

in activity under the motivation of hunger and its availability in large numbers" (p246);

� their use "only as a means of outlining problems an d

gaining clues which must in every case be retested by experiments with primates and by comparison with clinical evidence" (p246);

� "these lower animals seem to show the beginnings of

every human mental trait and I have come to doubt t hat the evolution of mammals has introduced any changes in the fundamental organisation or mechanism of cerebr al activity" (p246).

iii) Suction This is the removal of an area of the brain by inserting a fine tube called a cannula and applying suction, and is known as aspiration (Whatson 2004). iv) Temporary or transient lesion Techniques like freezing with cold liquids deactivate particular areas of the brain or an anaesthetic can be used. These processes do not permanently damage the brain. For example, Keenan et al (2001) studied five patients undergoing the intracortoid amobarbital (W ADA)


test for evaluation for surgery to treat epilepsy. This test inactivates one cerebral hemisphere through anaesthesia. Five right-handed (left hemisphere language-dominant) patients were shown pictures of morphed f aces (a combination of own face and a famous face) durin g the anaesthesia of one hemisphere. After recovery from the anaesthetic, the patients were asked between a pict ure of their won face and the famous face as to which was shown. All patients selected the "self" face after anaesth esia of the left hemisphere and four of them chose the f amous face after anaesthesia of the right hemisphere. The key finding for the researchers was the role of the rig ht hemisphere in self recognition. There are strengths and weaknesses to using th ese techniques which cause damage to study the brain (t able 11). STRENGTHS 1. Researchers can control which particular areas o f the brain to destroy. 2. Allows researchers to pinpoint particular areas of the brain to establish the function of that area. 3. Able to measure behaviour before and after the b rain damage. 4. Allows for replication of experiments. 5. Advantages over case studies of naturally occurr ing brain damage which is uncontrollable and unique to the individua ls involved. 6. It is possible to compare the behaviour of the n ormal and the abnormal brain. WEAKNESSES 1. Produces permanent brain damage in most cases. 2. The damaged brain is no longer a normal brain, a nd so the applicability of findings to the general population are open to question. 3. Ethics of such techniques with human or non-huma n animals. 4. Accuracy of destruction process - either damagin g the wrong area or causing extra damage beyond the area of focus. T his is particularly relevant in the past when techniques w ere not as sophisticated as today. 5. Side effects of the operation. 6. There is usually a time lag between the operatio n to destroy the brain tissue and the measurement of behaviour. Chan ges to the brain may occur during that time. Table 11 - Strengths and weaknesses of the delibera te destruction of brain tissue for understanding the b rain.


4.2. SPLIT-BRAIN PATIENTS There are situations where the brain has been deliberately damaged for medical reasons, like with split-brain patients. The brain is divided into two hemispheres whic h are connected by two hundred million nerve fibres known as the corpus callosum (figure 3). Split-brain patient s are a number of individuals who, for medical reasons, h ad the corpus callosum cut in an operation called a commissurotomy or callosotomy. Thus the two hemisph eres become separate (ie: unable to communicate).

(Source: Gray's Anatomy of Human Body, 20th US ed, 1918; in public domain)

Figure 3 - Drawing of brain from above showing corp us callosum. In the late 1950s, three individuals (WJ, NG, and LB; Gazzaniga 1995) with very severe epilepsy had t his operation, and it "virtually eliminated" the seizur es.


These individuals were studied, initially by Roger Sperry who was joined by Michael Gazzaniga (Hock 2002). Th e surgeons in California, Phillip Vogel and Joseph Bo rgen, performed nine operations between 1962 and 1968, an d more operations have taken place in the USA, France and Australia since then (Trevarthan 1987). Gazzaniga (1967) reported tests on the patient s. Different types of tests were developed to assess e ach hemisphere. 1. Visual test Individuals were asked to focus on a point in the middle of the screen, and information was flashed o n one side (visual field), so that only one eye could see it. This is known as the stimulus lateralization techni que. This was tried with a row of light bulbs. When those on the right side were flashed, the patient reporte d seeing them, but when on the left side, the patient claimed to see nothing. However, when asked to poin t at the light that flashed, the patient did equally wel l for both sides. What was happening? Information from the right side goes into the left hemisphere, which is also the ar ea for speech, and so the patient could answer the questio n. Information from the left side goes into the right hemisphere without language, and thus the patient c annot answer. Normally information passes between the hemispheres, and so this is not a problem. In one variation of this test, the researchers flashed a picture of a nude woman among the other pictures. When presented to the right eye, the fema le patient "verbally identified the picture of a nude" , but when presented to the left eye, "she said.. she saw nothing, but almost immediately a sly smile spread over her face and she began to chuckle.. Although the ri ght hemisphere could not describe what it had seen, the sight nevertheless elicited an emotional response like th e one evoked in the left hemisphere" (Gazzaniga 1967 p29) . 2. Tactile test The apparatus consisted of a screen through wh ich the individual could touch an object but not see it . When objects were touched by the right hand, the patient was able to name them. But when touched by the left han d, the patient could not name them. However, they were abl e to correctly pick it out from a choice of objects pres ented as pictures.


3. Visual and tactile test A picture of an object was shown to one eye an d the task was to feel for that object behind the screen. When a picture was presented to the left eye, patients d enied seeing anything, but they could find the object wit h their left hand behind the screen. Furthermore, a picture of a cigarette, for exa mple, could be shown to the left visual field, and the le ft hand could find a related object, like an ashtray, behind the screen. "Oddly enough.. even after their correc t response, ad while they were holding the ashtray in their left hand, they were unable to name or describe the object or the picture of the cigarette" (Gazzaniga 1967 p26). 4. Auditory test This type of test showed that the right hemisp here could comprehend language even if there is no speec h centre. Patients were asked to reach into a bag of objects with their left hand and find a particular thing, which they could do. The could also find objects described like "the fruit monkeys like best". But Gazzaniga (1998) has admitted that the ori ginal patients were unusual, and the right hemisphere may not be able to comprehend language at all. 5. Drawing test The patients were asked to copy a simple drawi ng, like a cube, which could only be seen by one side o f the visual field. Drawings presented to the left eye an d drawn by the left hand were more accurate. This is because the right hemisphere is better at spatial relationships. Gazzaniga (1985) has argued that the brain is really two brains because of the specialisation in ability in each hemisphere. Levy (1985), among others, has challenged this idea: "Normal people have not half a brain, nor two brains, but one gloriously different iated brain, with each hemisphere contributing its specia lised abilities" (p44). There are very rare cases of children born wit hout a corpus callosum, and it was found that information was being transmitted between the hemispheres (Hommet a nd Billard 1998). Gazzinaga (1998) reported a case that seemed t o suggest that communication between the hemispheres was happening in split-brain patients. For example, whe n the


word "bow" was flashed to one eye, and "arrow" to t he other, the patient produced a bow and arrow drawing s. But "we finally determined that integration had actuall y taken place on the paper, not in the brain". A pati ent shown the word "sky" in one eye and "scraper" in th e other produced a drawing of the sky above a scraper , and not a skyscraper which would have been integration as in the normal brain. However, the word "fire" followed by "arm", fo r example, presented to the left eye produced a drawi ng of a rifle from the patient. Thus each hemisphere is c apable of integrating information itself. The study of split-brain patients has strength s and weaknesses for understanding the brain (table 12). STRENGTHS 1. Possible to study rare cases and unusual events to understand more about the normal brain. 2. It has led to increased knowledge about the diff erent functions of each hemisphere and brain lateralisation. 3. The knowledge of the location of different abili ties has aided in treating individuals with injury to particular brai n areas (Hock 2002). 4. Well documented cases studied over many years. 5. Split-brains in humans have shown that the human brain is different non-humans. Split-brains in monkeys, for example, still show communicate between the hemispheres. 6. The original patients have been studied in many different ways over the years, and testing different hypotheses ab out the brain. WEAKNESSES 1. There are only a small number of such case studi es. 2. The brains of these patients are abnormal becaus e of the operation, which means they are not necessarily com parable to the normal brain. 3. It is not clear how much the epileptic seizures had damaged the brain before the operation. 4. The brain has changed post-operation. For exampl e, a few patients developed speech in both hemispheres (Gazzaniga 199 5). 5. Details of the original cases are not as well do cumented as modern cases where neuroimaging can establish the exact da mage. 6. The idea of two separate brains in one head has been challenged. Table 12 - Strengths and weaknesses of studying spl it-brain patients to understand the brain.


4.3. ARTIFICIAL STIMULATION This method involves stimulating the brain in some way to see the effect. It is usually chemical or electrical. Table 13 lists the strengths and weakne sses.

Table 13 - Strengths and weaknesses of artificial stimulation of the brain. i) Chemical stimulation The biochemistry of the brain can be altered b y chemical substances to see the effects. Chemicals c an be ingested (eaten or drunk) or injected. Micro-inject ions use thin needles that can inject minute quantities of chemicals into precise areas of the brain through a n opening in the skull. The technique of micro-iontophoresis (using micro-pipettes) can even influ ence individual neurons (Whatson 2004). Chemical substances can either mimic biochemic al processes (agonist drugs) or block the activity (antagonist drugs). For example, Harris et al (2005) were interest ed in the role of a neurotransmitter (orexin) in the late ral hypothalamus in reward-seeking behaviours. Male rat s were conditioned to associate one chamber of two with a reward (food, cocaine, or morphine). Injection of an orexi n antagonist reduced the preference for the rewarding chamber. Thus it was concluded that orexin must pla y a role in the brain in reward-seeking behaviour. While learning and memory can be studied by bl ocking

STRENGTHS WEAKNESSES

1. The researcher is able to see the exact effect of controlled stimulation. 2. It can be used with human and non-human animals. 3. Researchers are able to make baseline measures before the process begins which is not possible with naturally occurring changes. 4. Chemical stimulation is a good way to study the biochemistry of the brain. 5. It is possible to use with humans when the brain is operated upon for medical reasons.

1. Most studies involve small samples which makes it difficult to prove that the precise effect is the same for all. 2. Stimulation, particularly with drugs, can have more than one effect. Thus it is difficult to interpret the results. 3. Invasive. 4. Some processes can be irreversible. 5. The implanting of micro-electrodes in the brain changes the brain (ie: it is no longer a "natural" brain).


the consolidation of memory in mice with a drug tha t inhibits protein synthesis, for example. Mice can l earn the maze, but three hours later have no recall of t he correct path (Murphy and Naish 2004). ii) Direct electrical cortical stimulation (DE CS) This technique uses micro-electrodes to stimul ate the surface of the brain. 4.3.1. Wilder Penfield During operations on the brain (between 1920s- 50s), Wilder Penfield (figure B appendix) stimulated the surface of the exposed brain of individual undergoi ng brain surgery for epilepsy with a weak electric cur rent (box 3). Patients, who were conscious during the operation, reported vivid memories and perceptions: There is an area of the surface of the human brain where local electrical stimulation can call b ack a sequence of past experience... It is as tho ugh a wire recorder, or a strip of cinematographi c film with sound track, had been set in motion within the brain. The sights and sounds, and the thoughts, of a former day pass through the man's mind again (Penfield 1959 p1719).

Box 3 - Details of operation techniques as used by Penfield in 1930s. "Gentle electrical stimulation" of the tempora l lobe

Sterilization of scalp: local injection of nupercai ne in solutions of 1 : 1,500 and 1 : 4,000 to which adrenalin is added . The sterile towels are then arranged perpendicularly so that th e patient is cool, can see and move freely, and can be observed consta ntly. The role of anaesthetist is most important even though a genera l anaesthetic is rarely given, and in all of the records found in th is communication we are indebted to our anaesthetist, Miss Mary Roac h, who constantly followed the behaviour and movements of the patient s as well as their blood-pressure, pulse and general condition through the long and sometimes trying ordeal of electrical exploration o f the cerebral cortex. Osteoplastic craniotomy is used to expose large are as of the hemisphere, and the bone is replaced at the close o f operation. The exposed brain is kept warm by the heat of lights fo cussed upon it, and moistened with Ringer's solution applied with a n atomizer. Stimulation is carried out by either unipolar or bi polar platinum electrodeswhich emerge from a glass handle and are attached to insulated wires, all of which may be autoclaved (Pe nfield and Boldrey 1937 pp396-397).


in conscious patients produced sudden, powerful experiences which stopped when the electrode was re moved. "The conclusion is unavoidable that the music a pat ient hears or the appearance before him of his mother or friend are memories. It seems evident that in some way the stimulating electrode is activating acquired pa tterns of neuronal connexion which are involved in the mec hanism of memory. The patient considers and thinks over th ese hallucinations as he would a memory which he had hi mself summoned" (Penfield 1947 p343). Table 14 gives some examples of individual pat ients. In most cases, stimulation of the same area pr oduced the same experience "provided the interval between stimulations is not too short or not too long" (Pen field and Perot 1963 p682), but sometimes unconnected experiences were reported from stimulation of the s ame spot.

Table 14 - Examples of reports by patients when are as of cortex stimulated with electrodes. The responses of the patients were not made up , as with shown with "S.Be": "The surgeon then warned hi m that he was about to apply the electrode again. Then, af ter a pause, the surgeon said 'Now', but he did not stimu late. (The patient has no means of knowing when the elect rode is applied, unless he is told, since the cortex its elf is

PATIENT RESPONSE TO STIMULATION

S.Be "There was a piano over there and someone playing. I could hear the song you know". When the approximately sam e point was stimulated, he said, "Someone speaking to anoth er, and he mentioned a name but I could not understand it.. It was like a dream". The same point was stimulated again, he said, "Yes, 'Oh Marie, Oh Marie'. Someone is singing it", and again on the fourth time (Penfield 1959).

D.F Heard music, and "believed that a gramaphone (sic) was being turned on in the operating room" (Penfield 19 59).

R.W Heard mother talking on telephone when right tempor al cortex stimulated - "My mother is telling my brothe r he has got his coat on backwards. I can just hear them " (Penfield 1959).

R.R Stimulation of areas of the left temporal lobe prod uced recall of conversations in Johannesburg (Penfield a nd Perot 1963).

N.C An orchestra playing some music which she could not identify. She asked for the same point to be stimul ated until she recognised the piece of music. "The elect rode was clearly activating a neuronal record which she could not activate herself by any voluntary effort" (Penf ield and Perot 1963 p681).


without sensation). The patient replied promptly, 'Nothing'" (Penfield 1959 p1720). One patient, "J.V", reported the experience la sting after the stimulation had stopped. The experience o f voices shouting lasted for fourteen seconds beyond the two-second stimulation. While sometimes the experie nce could disappear before the end of the stimulation (Penfield and Perot 1963). Penfield and Perot (1963) admitted that: All of these patients were subject to tempora l lobe epilepsy which did, no doubt, make respo nse from the cortex easier to elicit. This is to be expected since localised epileptic discharge renders the motor cortex of man more easily stimulable, and sensory cortex as well. This increase in stimulability (decrease in thresh old) does not mean that the epileptic process is responsible for the nature of the response (p 683). But only 7.7% of patients reported such experi ences during the operations (Eysenck and Flanagan 2001). Penfield was also able to map the motor cortex by showing that stimulation to a particular area produ ced movement of part of the body (Lyon and McLannahan 2 004). Penfield and Boldry (1937), in particular, "confirm ed the precise tomography of cortical localisation, and we re able to relate stimulation of a discrete part of th e brain with motor and sensory phenomena affecting a particular part of the body" (Schott 1993 p329). iii) Deep brain stimulation This involves placing micro-electrodes inside the brain. In the 1950s, a technique called electrical stimulation of the brain was tried with animals (Ol ds and Milner 1954) and humans (Heath 1954) by placing electrodes in the limbic system. Figure 4 is a photograph of the type of electr ode used. The point is placed into the brain, and the t op end is attached to an electrical current. Jose Delgado (1969) implanted electrodes, whic h were radio-controlled, in the brains of cats, monkeys an d apes, bulls, and humans. He called the implants "stimoceivers". His most famous experiment from 1963 involved stopping a bull charging at him by stimulating its caudate nucleus (part of basal ganglia) in a bull-r ing in


(Source: Open Research)

Figure 4 - Deep brain stimulation electrode. Spain 2. Thankfully it worked to great public acclaim. However, "critics contended that the stimulation di d not quell the bull's aggressive instinct, as Delgado suggested, but rather forced it to turn to the left " (Horgan 2005 p70). Twenty-five humans had electrodes implanted by Delgado between the 1950s and 1970s at a mental hos pital in Rhode Island, USA. Stimulation of areas of the m otor cortex produced physical reactions, like clenching of the fist, that could not be resisted by the patient. Not surprisingly, such work (nicknamed "brain chips") was controversial. Though brain implants ar e used today with many individuals suffering from Parkinso n's disease (over 30 000 people)(Horgan 2005) 3. Carlson (1986) noted that "electrical brain stimulation is probably as natural as attaching rop es to the arms of the members of an orchestra, and then s haking all the ropes simultaneously to see what they can p lay.. the surprising finding is that stimulation so often does produce orderly change in the brain" (Carlson 1986) .

2 Photographs from original experiment at http://www.biotele.com/Delgado.htm. 3 This has led to modern developments in brain-computer interfaces (BCI)(Ohl and Scheich 2007).


iv) Trans-cranial magnetic stimulation (TMS) Trans-cranial electrical stimulation (TES)(Mer ton and Morton 1980) was the forerunner of TMS, but the use of electrical stimulation on the scalp was painful. TMS works indirectly, so that it does not stimulate the scalp and produce pain (Hallett 2000). TMS (Barker et al 1985) involves placing a mag netic coil above the scalp (with a focused pulse of magne tixm; Whatson 2004) which produces electrical currents in the neurons in the underlying cortex. This stimulates o r inhibits that area of the brain in a way that is no n-invasive and reversible. Amassian et al (1989) was one of the first stu dies to use TMS to study perception. Participants were s hown letters briefly on a computer screen, and TMS was delivered to the occipital cortex 80-100ms after. T he participants reported seeing a blur or nothing at a ll. Developing upon this finding, Beckers and Zeki (199 5) applied TMS to area V5 of the visual cortex, and th is interfered with motion perception. Applying TMS while the brain is scanned allows researchers to "see" the neural changes (Allen et a l 2007). Though the changes to the brain are reversible , there are concerns over the effects of TMS. Short durations of TMS can produce effects lasting hours and even days (Allen et al 2007). For example, short TM S pulses of less than one minute were found to suppre ss neural activity for 5-10 minutes in cats (Allen et al 2007). TMS has been developed and expanded in differe nt ways (Huang et al 2009), like: � Theta burst stimulation (TBS) - Either continuous

(cTBS) or intermittent (iTBS), which uses 50Hz burs ts every 200ms to disrupt activities in the cells;

� Controllable pulse shape TMS (cTMS) - Greater contr ol

over the strength of the electrical field generated . Knoch et al (2006) applied low-frequency repet itive TMS (rTMS) for fifteen minutes to areas of the dorsolateral prefrontal cortex (DLPFC) while partic ipants played the Ultimatum Game. This game is used to tes t fairness and co-operation. A proposer has a certain amount of money, and offers to share it with the responder. The proposer can offer any amount of mon ey. If the responder rejects the offer, both players recei ve nothing, but if they accept, the money is divided


accordingly. Many responders reject offers if they are not perceived as fair (eg: below 25% of available money ). This goes against economic self interest which woul d accept any offer as better than zero. Acceptance rates for unfair offers in this experiment were 10% at baseline. With right DLPFC T MS this increased to 45%, but not with left side TMS. TMS "switched off" the area of the brain, and the participants were less able to resist the "economic temptation" of the offers. The DLPFC (right side, i n particular) seems to be involved in over-riding "se lfish impulses". However, the participants still knew the offer was unfair even with TMS and accepting it. 4.3.2. Studying Temporal Aspects of Perception Researchers studying the brain tend to use a combination of methods, and use newer techniques to confirm and develop findings from other methods. Th is is the case with TMS studies and visual perception. Visual perception involves a number of process es and aspects that have been studied (Battelli et al 2008 ): � "Primary features" - The "physics" of the visual

stimulus (eg: light wavelength); � Spatial components - The parts of the stimulus in

relation to each other, and the stimulus in space; � Semantic components - The meanings attached to the

stimulus (eg: predator approaching) and thus the ac tion required.

Take the example of a stimulus approaching. De tails of the shape and motion are the primary features th at reach the eye, and the spatial aspects relate to th e direction. The semantic aspect is the fact that the stimulus is a charging bull. Battelli et al (2008) added another aspect of visual perception - a temporal component. This is the brai n registering the time involved in the sequence of ev ents, their duration, and the interval between events in order to co-ordinate action. As the bull approaches, the visual information has to be ordered into a correct sequen ce to show that the bull is moving towards the viewer bef ore action is taken. Without a temporal sequencing of e vents it would be difficult to tell if the bull was runni ng towards or away from the viewer. The time involved may be milliseconds, but time is being processed as part o f the visual information. "The role of time at this scale is not so much to underpin the experience of time but to establish the ordering and nature of the flow of ev ents" (Battelli et al 2008 p120).


The time aspect of visual perception includes marking the arrival and the disappearance of of a stimulus in the visual field (opening and closing transients; Battelli et al 2008). The intervening p eriod between them is the duration of the stimulus's pres ence. If the arrival is not marked, the stimulus will not be seen. While if the disappearance is not marked, ano ther stimulus may be perceived as part of the original stimulus in motion. For example, two lights close together flashing on and off consecutively appear t o be one light moving. Using the rapid serial visual presentation par adigm (RSVP), two letters are presented very quickly one after the other at the same point on the computer screen. If the time between them is faster than 400ms, the sec ond letter is not seen. This has been called the attent ional blink (AB) phenomenon (Battelli et al 2008). The temporal aspect of perception involves particular parts of the brain together called the " when" pathway, which goes with the "where" pathway (establishing the position of the stimulus in space and motion; "dorsal stream" involving inferior parietal lobe) and the "what" pathway (establishing what the stimu lus is - form and face recognition; "ventral stream" invol ving inferior temporal lobe)(Cacioppo et al 2008). Becau se the processing of information is so quick, the experien ce of visual perception is a combination ofthese pathways . We just "know" the stimulus is a bull charging at us. Work with non-human primates (eg: Saalmann et al 2007) has shown that the lateral intraparietal cort ex (LIP) is involved in the "when" pathway. Isolating the temporal aspect of perception oc curs when there is damage to the brain which produces de ficits in visual perception. In humans this means waiting for naturally occurring brain injuries to occur. That i s until the development of TMS which is able to produ ce transient "damage" to the brain. Both observations from brain injuries (eg: Bat telli et al 2003) and TMS studies (eg: VanRullen et al 20 08; box 4) have confirmed that the right parietal corte x (figure 5) is involved in temporal processing in perception. The "when" pathway has been expanded to the "extended when" pathway to include anticipation of when an event will occur, and estimation of the duration of the period from one event to the predicted next tim e. This is "when-past", "how long", and "when-future" (Battelli et al 2008). TMS studies have shown that other areas of cortex are involved in the "extended when" pathway. This pathway also includes other senses th an vision. Battelli et al (2008) proposed that "each s ensory


system will have its own 'when' pathway originating in sensory cortex and taking a route through the parie tal and motor related cortices" (p124). In understanding the "when" pathway in percept ion, TMS studies are being used to confirm and develop findings from intervention studies with non-human primates, case studies of brain injured human patie nts, and EEG studies (eg: VanRullen et al 2006)

(Source: Joint effort on English Wikipedia; last pa rt: King of Hearts; in public domain)

Figure 5 - Brain showing different lobes.

Box 4 - VanRullen et al (2008).

VanRullen et al (2008) used TMS while participants viewed the "continuous Wagon Wheel illusion" (c-WWI). This ill usion is where a wagon wheel appears to rotate in the opposite direc tion to is actual rotation. The researchers explained the illusion in relation to the "when" pathway failing to sequence the temporal asp ects of perception correctly. Disruption of the right parietal lobe wi th TMS weakened the illusion.


5. STUDYING NATURALLY OCCURRING BRAIN DAMAGE The aim here is to study naturally occurring b rain damage in order to gain clues about the healthy bra in. There is no manipulation of the brain by the resear cher, simply the study after the event. Acquired brain in jury is generally through injury (eg: closed head injury ) or illness (eg: stroke), and is studied by the case st udy method. 5.1. BRAIN INJURY/DAMAGE FROM BIRTH Most research studies individuals, usually adu lts, who suffer brain injury, but there are rare conditi ons where the individual is born with brain abnormaliti es. One such condition is "agenesis of the corpus callosum" (ACC) where the corpus callosum is partia lly or completely absent (Aribandi 2008). It is due to a g enetic fault which hinders the normal brain development in the first trimester of gestation. ACC is usually associated with other central n ervous system anomalies (85% of cases). This does effect t he usefulness of studying such cases (table 15). Overa ll the condition is relatively rare (eg: 0.7 - 5.3% in the USA; Aribandi 2008), but more common in males.

Table 15 - Strengths and weaknesses of studying nat urally occurring brain injury from birth. 5.2. ACQUIRED BRAIN INJURY/DAMAGE These are cases where individuals have acquire d brain damage later in life through injury (eg: Phin eas Gage) or illness.

STRENGTHS WEAKNESSES

1. Possible to follow the development of individuals with such brain abnormalities. 2. Does not involve any intervention to cause brain abnormality. 3. Modern scanning techniques give details of the brain area damaged.

1. Usually have multiple areas of brain abnormality which limits the comparison of single area damage to healthy controls. 2. Many individuals do not live very long, even to adolescence. 3. Problems of studying such infants.


5.2.1. Phineas Gage One of the best known case studies of brain in jury is that of 25-year-old Phineas Gage (Harlow 1848) 4. He was a US railroad building foreman who suffered the freak accident of a three-foot long tamping iron being propelled through his skull by an explosion (figure 6). The iron entered the left cheek and exited the back of the skull causing damage to the left pre-frontal co rtex. "Beyond the astonishing fact of Mr.Gage's surv ival was the description of his ability to walk immediat ely after the event, communicate sensibly, and remain l ucid through most of the period following the injury" (N eylan 1999).

(Source: Harlow 1868; copyright expired; in public domain)

Figure 6 - Drawing of tamping iron through Gage's s kull. John Harlow was the local doctor, and was call ed to help Gage about two hours after the accident: "He s eemed to be perfectly conscious, but was getting exhauste d from the haemorrhage, which was very profuse both extern ally and internally.." (Harlow 1848). The accident happened at 4.30pm on Wednesday 1 3th September (1848) near Cavendish, Vermont, and for t he following month Gage slept a lot and has problems w ith the would healing, typical of the time and medical knowledge. On 11th October, Harlow (1848) wrote: "Intellectual faculties brightening.. Relates the m anner in which it {accident} occurred, and how he came to the

4 Details were also reported in Bigelow (1850a and 1850b), Harlow (1849, 1868, 1869), and Anonymous (1851).


house.. says he knows more than half of those who inquired after him. Does not estimate size or money accurately, though he has memory as perfect as ever ." He returned home to his family at the end of November. Before the accident, he was described as havin g "temperate habits, and possessed of considerable en ergy of character" (Harlow 1848). Full details of the ca se were reported in Harlow (1868), and the focus was u pon the change in the personality of Gage: His contractors, who regarded him as the most efficient and capable foreman in their employ ment previous to his injury, considered the change in his mind so marked that they could not give h im his place again. He is fitful, irreverent, in dulging at times in the greatest profanity (which was not previously his custom), manifesting but littl e deference for his fellows, impatient of restr aint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capriciou s and vacillating, devising many plans of futur e operation, which are no sooner arranged than they are abandoned in turn for others appearing mo re feasible (Harlow 1848 quoted in Neylan 1999 p 280). Overall he was described as "no longer Gage" b y friends and colleagues. He was forced to leave his job and wandered ar ound for much of the rest of his life including a spell in Chile and ended up in San Francisco (where he died) . Ferrier (1878) was the first to argue that the damage caused by the iron rod missed the motor and language centres of the brain, behaviours which wer e unaffected, but the damage to the left pre-frontal cortex caused the "mental degradation". Gage died twelve years after the accident. No post-mortem study of the brain took place as Harlow only learned of Gage's death five years after it occurre d (Damasio et al 1994), but the skull was later recov ered. Measurements from the skull have been made to try and establish the exact brain damage. Subsequent st udies have suggested damage to the right pre-frontal cort ex as well as the left. Damasio et al (1994) believed tha t the behaviour changes shown by Gage were typical of gen eral damage to areas of the whole pre-frontal cortex, an d seen in recent cases of pre-frontal cortex injury: "Thei r ability to make rational decisions in personal and social matters is invariably compromised and so is their processing of emotion. On the contrary, their abili ty to tackle the logic of an abstract problem, to perform calculations, and to call up appropriate knowledge and attend to it remains intact.." (p1104).


The case study of Phineas Gage has a number of strengths and weaknesses for understanding the brai n (table 16). STRENGTHS 1. Detailed notes about Gage immediately after the accident from Dr.Harlow. 2. Insight and detail of an outstanding and rare ca se. 3. Possible to study brain damage that cannot be pr oduced by an experiment with human participants. 4. Exceptional cases like this encourage research t o discover more. 5. Freak accidents like this can highlight aspects of the brain not considered at the time (eg: frontal cortex and self control). 6. It is the nearest to "turning off" part of the b rain to see the effect. 7. There are not ethical or moral issues as with ex periments on non-human animals or humans. 8. Case studies produce rich, qualitative data. WEAKNESSES 1. No post-mortem study of the brain, so the exact area of damage is not known. 2. Because case studies like this depend upon accid ents, there are few details and measures from before the event. Exp eriments are able to gain measures before and after the event. 3. Dependent upon the records kept by witnesses of the time. Though Harlow was a doctor, his records are not as detaile d as those of modern medicine. 4. It is not advisable to generalise the findings f rom unique cases. 5. The damage to the brain is haphazard, so it is n ot really like experimentally "turning off" part of the brain. 6. Experiments with non-human animals would allow r esearchers to control the variables and isolate the exact cause a nd effect relationship. 7. Researchers may become involved with the case, a nd thus their reports lack objectivity. 8. Case studies are often low on quantitative data, which are more objective. Table 16 - Strengths and weaknesses of the case stu dy of Phineas Gage for understanding the brain. Macmillan (2000) was interested in how the Gag e case


was reported in psychology and psychiatry textbooks . he estimated that details appeared in 60% of such text books published between 1983 and 1998, and, in many cases , with errors. The errors related to seven elements of the story: � Dimensions of the tamping iron. � Gage's work - reports included that he was a miner or

building a road. � Circumstances of the accident. � Damage done to Gage's skull and brain. � His treatment and recovery - one report had Gage

walking to the doctor's office with the tamping iro n still through his skull, and another described him as living for twenty years with it still in his skull.

� Changes in personality and behaviour (table 17) - i n an

extreme case, Gage "virtually became a psychopathic personality who lied and could not be trusted to ho nour his commitments" (Macmillan 2000 p54).

� His life after the accident - for example, Harlow s aid

nothing about Gage's drinking, but a few textbooks reported him as "frequently drunk".

Table 17 - Key details about Phineas Gage from prim ary sources (Macmillan 2000). 5.3. BRAIN INJURY/DAMAGE THROUGH ILLNESS Brain damage and injury can occur through illn ess, of which one of the most common is stroke. Blood fl ow to part of the brain is restricted and the area is

PRE-ACCIDENT POST-ACCIDENT

� "temperate habits" (Harlow 1848)

� "possessing an iron will as well as an iron frame" (Harlow 1868)

� "well-balanced mind.. very energetic and persistent in executing all his plans of operation" (Harlow 1868)

� "he was gross, profane, coarse, and vulgar, to such a degree that his society was intolerable to decent people" (Anonymous 1851)

� "The equilibrium or balance.. between his intellectual faculties and his animal propensities, seems to have been destroyed. He is fitful, irreverent.. manifesting but little deference for his fellows" (Harlow 1868)


consequently damaged. Stroke can lead to visual agnosia (an inabilit y to recognise familiar objects) and prosopagnosia (an inability to recognise familiar faces). Aviezer et al (2007) reported the case of SE, a 52 year-old Israeli man who suffered a stroke in 2004. He was unable to visually recognise common objects and faces, though tactile and auditory recognition were unaffected. He also had problems with colour percep tion, and orientation (eg: difficulty describing how to g et home). He was tested two months after the stroke. SE could match geometric shapes, and copy and name simple figures (eg: square). But for drawings of co mplex objects, he scored 26% correct recognition (eg: a mushroom mistaken for a parachute). Despite not bei ng able to name the object, he was able to give inform ation about the purpose of the object and copy it accurat ely from memory. This showed that the problem was not r elated to semantic memory. In another test, an object was named and SE ha d to point to the correct line drawing out of five. He h ad a success rate of 77%. In a test with Navon hierarchical letters (Nav on 1977)(figure 7), he could not recognise the global letter even when pointed out, only the local letters.

Figure 7 - Examples of Navon's hierarchical letters . In the congruent condition (same global and lo cal letters), shown for 450ms, SE recognised the global letter in 61% of trials and 73.4% for the local let ters. For the incongruent condition, the correct trials w ere 33% and 73.2% respectively. Aviezar et al tested for unconscious recogniti on of objects. SE was shown a drawing of an object (which he could not recognise) for 300ms, followed by a word. His task was to say as quickly as possible if the word was an animate or an inanimate object. Some preceding draw ings were the same as the word, others were not. If he h ad unconscious recognition, his reaction time would be faster when the drawing was the same as the word.

EEEE YYYY E Y EEEE YYYY E Y EEEE YYYY Congruent Incongruent


The reaction time for the "same" condition was 2076ms compared to 2328ms for the "different" condi tion. So it seemed that SE had unconscious recognition of objects, and the problem was the conscious recognit ion of them. This was confirmed when the last experiment w as repeated using scrambled drawings. Here there was n o difference in reaction times between the two condit ions. Some improvements in visual recognition abilit ies were found when SE was tested nine months after the stroke. SE also suffered from prosopagnosia, and could not even recognise faces known before the stroke, inclu ding famous people, family members, and himself. Further more, when presented with faces with parts changed (eg: a pples instead of eyes), he recognised the objects but not that the stimuli were faces: "here are some fruits (poin ting to the eyes).. judging by their shape, they are app les.. and these (points to nose and mouth) might be branc hes.. and this here (points to circular outline of face) might be a plate". But occasionally, he did "see" the fac e in such a stimuli when pointed out to him. A problem with testing was that SE used semant ic information, like context, to aid his recognition o f objects. For example, when in an office, it was not iced that he recognised a stapler, a pen, and other expe cted objects, but not unexpected objects. This showed th at his was using top-down information in visual perception . Aviezer et al tested this experimentally. The task was to say if a line drawing was a po ssible or an impossible object. Before each drawing, SE wa s shown a word for 1500ms. The word, known as the pri mer, was either for the same object or not in the follow ing drawing. Where the word was the same as the possibl e object, SE was 82% accurate in naming the drawing ( 50 out of 61 trials), but when the word was different to t he drawing, 50% accuracy (21 out of 42). For the drawings of impossible objects, he got 69% correct but took a long time (average 13.5 seconds) . 5.3.1. Clive Wearing On 29th March 1985 Clive Wearing collapsed and was admitted to hospital with encephalitis (inflammatio n of the brain) caused by the herpes simplex 1 virus (wh ich causes cold sores usually)(Wilson and Wearing 1995) . In rare cases like this, the virus is dormant near the spinal column, "wakes up" and heads for the brain. The subsequent inflammation of the brain caused damage to the


hippocampus, which is linked to memory 5. After hospital he showed many symptoms of conf usion, not understanding speech, and repeating meaningless phrases. He went through a phase of backward spelli ng and talking. The world seemed to be continually changin g for him as he could not retain information for longer t han the briefest time. He showed epileptic and Parkinso n's symptoms like jerking and shaking. Confabulation is also common. Clive is unable to lay down new memories, and has a limited number of memories from before the illness. He is in a permanent state of feeing that he has just wok en up that minute (with a memory span of seconds) from "unconsciousness". He keeps a diary compulsively (w hich began on 7th July 1985): "7.46am: I wake for the first time. 7.47am: This illness has been like death till NOW. All senses work. 8.07am: I AM awake. 8.31am: Now I am really, completely awake. 9.06am: Now I am perfectly, overwhelmingly awake. 9.34am: Now I am superlatively, actually awake (Wea ring 2005 quoted in France 2005) 6. "Clive's world now consists of a moment with n o past to anchor it and no future to look ahead to. It is a blinkered moment.. So it's a moment to moment consciousness as it were.. a time vacuum" (Deborah Wearing speaking on BBC documentary, "The Mind Mach ine", in 1988 quoted in Wilson and Wearing 1995 p15). Yet he remembers his wife, Deborah, but not hi s wedding nor his children's names (France 2005). The re are some intriguing behaviours like learning the route to the hospital dining room and back to his room over seve n years. Though he did need his name to be on his doo r. Also "After the first few years post-insult, when t alking to his wife he began to abbreviate his questions [ "How long?" = "How long have I been ill?"; this suggests that, at some level, he is aware he must have asked them before" (Wilson and Wearing 1995 p27). Clive's semantic memory (general knowledge) is less affected, but its usefulness is limited because of the severe damage to the episodic memory (autobiographi cal

5 A MRI scan in 1991 showed damage in the temporal lobe, especially the left, including almost complete disappearance of the hippocampus (Wilson and Wearing 1995). 6 Clive reported auditory hallucinations in his diaries as a "master tape" ("what he thinks is a tape of himself playing in the distance"; Wilson and Wearing 1995).


memories). His IQ was tested as 106 immediately aft er hospital, and estimated as 120-140 pre-illness (Wil son and Wearing 1995). Before the illness, he was an accomplished mus ician, and he still retains these ability - to sight-read music, to play the piano and organ, sing and conduct a cho ir (Sacks 2007). Barbara Wilson made the first formal assessmen t of his amnesia between November 1985 and May 1986 (Wil son and Wearing 1995) using different psychometric test s: � Rivermead Behavioural Memory Test (Wilson et al 198 5) -

This involves twelve tasks related to everyday life (eg: remembering a person's first and last names; remembering an appointment)(Strauss et al 2006);

� Wechsler Memory Scale (Wechsler 1945) - Recall of p rose

passage immediately and after delay; � Rey Osterreith Complex Figure Test (Osterreith 1944 ) -

The task is to copy a drawing of a complex figure f rom memory;

� Autobiographical Memory Interview (AMI)(Kopelman et al

1989) - Recall on personal semantic questions (fact s from own past life) and autobiographical incidents (specific incidents in own life);

Clive's performance on each test is detailed i n table 18.

Table 18 - Clive Wearing's performance on memory te sts in 1985-6. Clive was formally assessed in 1989, 1991 and 1992 by Wilson. The scores on the different memory tests were unchanged including an immediate recall of six digi ts (forward) and four backwards. His IQ seemed to have dropped to 97 (Wilson and Wearing 1995).

TEST CLIVE'S PERFORMANCE

Rivermead Behavioural Memory Test 0/12

Wechsler Memory Scale immediate recall - 1 delayed recall - 0 (and confabulation)

Rey Osterreith Test No delayed recall

AMI Abnormally poor


Other tests used included the Graded Naming Te st (GNT)(McKenna and Warrington 1983) which tests nami ng of thirty objects (eg: corkscrew, handcuffs) and thirt y proper names (eg: Hitler, Shakespeare) 7, and a semantic memory test 8 (Hodges et al 1992) on which Clive was similar to a moderate Alzheimer's sufferer)(table 1 9).

(After Wilson and Wearing 1995)

Table 19 - Percentage of total items correct on sem antic memory test.

7 The logic behind this test was a case study of "GBL", who had stroke damage to the left hemisphere, and showed perfect naming of objects, but poor naming of famous people (McKenna and Warrington 1980). 8 This tests knowledge with tasks that involve naming pictures (eg: birds), naming items described, and matching words to pictures.

Categories: LIVING NON-LIVING

Naming pictures (out of 24) Naming to description (out of 12) Word-picture matching (out of 24)

46 17 71

83 67 100


6. RECORDING ELECTRICAL ACTIVITY 6.1. ELECTROENCEPHALOGRAM (EEG) This method records the general electrical act ivity of the brain by attaching electrodes to the scalp. The brain waves vary in frequency (the number of oscill ations per second), and in amplitude (measured as half the height from the peak to the trough). One complete oscillation is a cycle, and cycles per second (cps) are measured. Hans Berger (1929) is seen as the first report of human EEG (figure 8).

(Source: Berger 1929; in pubic domain)

Figure 8 - First human EEG recording. EEG readings show four major types of brain wa ves: � Beta waves (13 cps or more) - recorded in adults aw ake

and alert; � Alpha waves (8-13 cps) - recorded in adults awake, but

relaxed; � Theta waves (4-7 cps) - mainly in young children; � Delta waves (1-3 cps) - mainly in infants, and slee ping

adults (Gross 1992). Table 20 lists the advantages and disadvantage s of EEG, and in relation to the other methods of record ing electrical activity. 6.2. EVOKED POTENTIALS OR EVENT-RELATED POTENTIALS This is the measurement of small groups of cel ls, and is more sensitive than EEG. Recordings are made on the scalp and neck away from main EEG regions of sp inal cord, brainstem and cortex. Measuring the response to a specific stimulus by groups of neurons is measuring event-related potent ials.


Table 20 - Advantages and disadvantages of EEG. 6.3. MAGNETOENCEPHALOGRAPHY (MEG) This technique makes use of changes in the mag netic fields in cortical neurons, which can be detected b y magnets placed on the scalp. Liquid helium coiled superconducting sensors (eg: single superconducting quantum inference devices; SQUIDS) are used to pick up the faint magnetic fields. It is able to detect cha nges in signals over milliseconds, but it does not have the localised accuracy of MRI scans. "GY" is a man in his 50s who, due to a car acc ident as a child, has brain damage that limits his visual abilities. He is "functionally blind" on his right side, but can "guess" correctly stimuli shown in this vis ual field. This is known as "blindsight". He was tested using a whole-head MEG system "w ith 151 radial gradiometers over the head and 29 refere nce gradiometers and magnetometers for ambient field correction. Signals were digitised at a sampling ra te of 1250Hz (0-200Hz bandwidth) during epochs lasting fi ve seconds, beginning one second prior to stimulus ons et" (Schurger et al 2008 pp2190-2191). The researchers were able to identify neural responses to awareness of a target and attention-wi thout-awareness of a target in the blind field. The neuro ns that fire are similar in both cases. 6.4. SINGLE UNIT RECORDING The activity of single neurons can be measured by invasive microelectrodes placed in the brain. This is different to other techniques for recording electri cal activity which do not go inside the brain. The most famous use of this technique was by H ubel

ADVANTAGES DISADVANTAGES

1. Measures electrical activity of whole brain. 2. Ability to measure whole hemisphere activity. 3. Easier to perform than single unit recording. 4. Non-invasive. 5. Both the waking and sleeping brain can be studied.

1. Measuring whole brain's electrical activity tells us little about specific area activity. This is overcome by using the other techniques of recording electrical activity. 2. Only indirect measure of brain activity because electrodes on scalp. Invasive techniques of recording overcome this problem.


and Wiesel (eg: 1959, 1962) who mapped the visual c ortex of a cat by recording visual activity in response t o different visual stimuli. They found different cell s in the cortex that responded to different line orienta tions. The cerebral cortex is highly developed in mammals, and may include over 100 000 neurons for each square millimetre. The primary visual cortex (or striate c ortex) occupies the area at the back of the brain (occipit al lobe). Hubel and Wiesel began their work in 1958, and the first set of results were published a year later. F urther details were then reported in 1962. Alongside this work on single cell recording, Hubel and Wiesel studied the development of the visual system in kittens where o ne eye was surgically closed (Hubel and Wiesel 1998). In the single cell recording experiments, the cats were paralysed by anaesthetic, but remained conscio us. The researchers used minute micro-electrodes to mea sure the electrical activity of individual brain cells a t the back of the surface of the brain. Lines of different angles and orientations wer e shown on a screen in front of the cat's eyes. Painstakingly, the researchers measured the respons e of individual cells, and built up a picture of how cel ls in the visual cortex work. Hubel and Wiesel (1959) identified three types of cells in the visual cortex: i) "simple cells" - these cells respond to particular features of the line only (eg horizontal ), and in particular locations of the visual field; ii) "complex cells" - these cells respond to particular orientations also, and receive informati on from the simple cells; iii) "hypercomplex cells" - these cells are al so sensitive to the length of the line, and receive information from the complex cells. The information from each cell is processed in an upward direction (ie: from simple to hypercomplex). Working downwards through the cortex, the researche rs found that the cells were stacked in "ocular domina nce columns". In a more recent example, Romo et al (1999) re corded the activity of single neurons in the prefrontal co rtex of four monkeys during a task to discriminate betwe en two mechanical vibrations to the fingertips. Four hundr ed and ninety-three neurons were recorded by seven moveabl e microelectrodes.


7. COMPUTER TOMOGRAPHY/NEUROIMAGING Brain scans can be used in a number of ways: i) To study the biochemistry in the brain. ii) For the measurement of cerebral blood flow or regional blood flow (rCBF) to particular areas of t he cortex. For example, PET scans show a time lag of 1-3 seconds for blood flow rises after the start of activity in an area of the brain where there is low rCBF. iii) Closely linked to (ii) is the measurement of cerebral metabolism; eg: the rate of use of oxygen or accumulation of deoxyglucose shows the active parts of the brain in PET scans. It is possible now to study regional glucose metabolism (rCMRglu) in specific a reas of the cortex, using, for example, 18 F-deoxygluco se (18-FDG). iv) To assess structural brain differences; eg : the reduction in certain brain areas in CAT scans. "With these new imaging techniques, researcher s interested in the function of the human brain were presented with an unprecedented opportunity to exam ine the neurobiological correlates of human behaviours" (Raichle 2003 p3959). Cacioppo et al (2008) noted the impact of neuroimaging: "The detailed three-dimensional colou r images provided by neuroimaging, modelling statisti cal properties of the working brain, have captured the imagination of the public and the science community , shaped funding priorities at federal funding agenci es and foundations, and produced a dramatic growth in scie ntific papers and journals in the area" (p62). The popularity of studies using neuroimaging techniques can be seen in the number of papers reco rded on PubMed 9 - nine using fMRI in 1993 to 2139 in 2007 (Poldrack and Wagner 2008). Neuroimaging has a number of advantages and disadvantages (table 21).

9 This is a database of medical and related academic research provided by the US Library of Medicine and the Nationa Institutes of Health (http://www.ncbi.nlm.nih.gov/pubmed/).


Table 21 - Advantages and disadvantages of neuroima ging. There are a number of different neuroimaging techniques which show the structure or function of the brain (table 22): � Computerised axial tomography (CAT) � Positron emission tomography (PET) � Single-photon emission computed tomography (SPECT) � Magnetic resonance imaging (MRI) � Magnetic resonance spectroscopy (MRS) � Functional magnetic resonance imaging (fMRI) Neuroimaging studies in recent years have both confirmed and challenged existing theories and idea s in psychology, and especially in cognitive psychology (table 23).

ADVANTAGES DISADVANTAGES

1. Detailed picture of the living brain. 2. Pictures of the brain in 3-D. 3. Able to watch changing brain including blood flow patterns. 4. Able to detect damage to the brain. 5. Comparisons can be made between individuals or by looking at the same brain area in the same individuals at two different times. 6. Non-invasive. 7. Some techniques have no know health risks; eg: MRI (Berger 2002). 8. So much more information about the brain than other methods.

1. Health risks with some techniques. 2. Expensive to use. 3. Scanners can be noisy and confined spaces to remain still in for long periods of time (eg: 3 hours for fMRI). 4. Require large computing capacity to convert raw data into visible images. 5. Some methods have time lags between brain activity and measurement; eg: fMRI measures blood flow approximately one second after neuronal activity (Raichle 1994). 6. Some techniques produce better quality images than others. 7. How to interpret the results. 8. Ethics of claims about such techniques.


Table 22 - Different techniques of neuroimaging.

Table 23 - Neuroimaging studies and existing ideas in cognitive psychology. 7.1. COMPUTERISED AXIAL TOMOGRAPHY (CAT SCANS) First used in 1972 (Sadock and Sadock 2003), t his method produces a 3D X-ray picture of the static br ain based on many X-rays from different angles and then combined together by the computer. X-ray machines are based on the principle that abnormal tissue absorbs X-rays to different degree to normal tissue. It is best at showing the presence o f blood clots, tumours, and enlarged ventricles. There is a small risk from the X-rays if CAT s cans are used too often on the same individuals. Owens et al (1985) performed a British study b ased on a sample of 112 hospitalised patients with schizophrenia. CAT scan results showed that lateral

TECHNIQUE STRUCTURE OR FUNCTION

MAIN ADVANTAGE MAIN DISADVANTAGE

CAT S Detect damage in brain

Health risks of X-rays

PET F Shows active brain Health risk of radioactivity

SPECT F More sensitive than PET

Shows activity over 60-second period rather than moment by moment (Eysenck and Flanagan 2001)

MRI S Detailed picture of brain anatomy

Cannot show function

MRS F Shows brain's chemical compounds

Requires very low temperature to work (ie: 4 degrees above absolute zero)

fMRI F Shows localised brain activity

Need for patient to be perfectly still for long periods

EXISTING IDEA FINDING FROM NEUROIMAGING STUDY

Short-term memory and long-term memory distinctively different

Challenged: Unitary model of memory (Nee et al 2008)

Declarative memory in hippocampus, but not non-declarative memory

Confirmed: Knowlton and Foerde (2008)


ventricular size increased more often in the patien ts than controls. In other words, the brain volume was reduced. The type of treatment was found to play no role either. These findings were constant over the lengt h of the illness suggesting it was not a product of the disorder (Lewis 1996). This method has been supplanted by others, exc ept for assessing calcification, which may be invisible on MRI (Sadock and Sadock 2003). 7.2. POSITRON EMISSION TOMOGRAPHY (PET SCANS) This technique is able to show the active brai n by following the movement of a radioactive substance t hat has been injected into the brain (figure 9). Radioactivally labelled glucose molecules travel to active areas of the brain. When the radioactive ato ms decay, they emit positrons (sub-atomic particles). These encounter electrons (the opposite type of particles ) and both are annihilated. This gives rise to gamma rays that travel in opposite directions, and these can be tra ced to the point of origin. Its strength is the ability to show blood flow patterns in the brain, which can be affected by, fo r example, strokes. Different radioactive tracers (eg: water label led with oxygen isotope 15O) can be used to target diff erent aspects of the brain's activities, like blood flow, glucose metabolism, dopamine receptors, or MAO acti vity (Grasby et al 1996). Because a small amount of radioactivity is inv olved, the World Health Organisation recommends one PET Sc an per five years. 10 PET scans or 2 SPECT scans are the s ame as annual background radiation exposure (Liddle 1996). Baxter et al (1992) performed a study based up on 18 patients with obsessive-compulsive disorder given e ither drug therapy or behaviour therapy. Initial PET Scan s showed high levels of activity in the caudate nucle us in the right hemisphere when suffering an attack of th e disorder. Thirteen of the patients responded to the trea tment, and, in a second PET scan, the caudate nucleus was less active.


(Source: US Department of Health and Human Services ; in public domain; http://www.nia.nih.gov/Alzheimers/Resources/HighRes .htm )

Figure 9 - PET scan of healthy brain (top) and Alzheimer's disease brain (bottom). Raichle et al (1994) used PET scans to show th at different parts of the brain are active during the process of learning. Participants were asked to gen erate a verb to go with a noun (eg: hammer). Forty nouns were presented at a rate of one every 1.5 seconds. This was the "naive" condition, and areas of the brain like the left prefrontal cortex and anterior cingulate corte x were active. Then the task was repeated ten more times with the same nouns. This was the "practised" condition, and participants produced stereotyped responses over ti me. Now there was less activity in the cortex areas tha n in


the naive condition. In the third ("novel") conditi on, new nouns were introduced and the brain activity re turned to the same as the naive condition. Brain activity is different for new and learned tasks. 7.2.1. Single-photon emission computed tomography (SPECT) This is a more sensitive measure of blood flow in the brain. It makes use of exametazime labelled wit h technetium isotope, 133mTc, for example (Liddle 199 6). 7.2.2. Hippocampus and London Taxi Drivers Maguire et al (1997) used PET scans to study t he hippocampus (figure 10) and spatial (or topographic al) memory of eleven male London taxi drivers. All the men has passed the stringent examination of their recal l of London streets (known as "The Knowledge") to become licensed. The participants were tested on different task s (in each case twice): � Routes - describe the shortest route between a star ting

and a destination point in London (recall of topographical knowledge involving the sequencing of information);

� Landmarks - describing the appearance of world-famo us

landmarks (not in London) that they had never visit ed (recall of topographical knowledge);

� Film plots - recall the plot of a familiar film (se en

five times or more)(recall involving sequencing of information);

� Film frames - recalling individual frames from famo us

films; � Baseline - repeating two four digit numbers (contro l

task). Blood flow (rCBF) to areas of the brain was us ed as the measure of activity in response to a particular task. Each task showed a slightly different pattern of br ain activation (table 24), but the routes task involved activation of the right hippocampus, in particular, compared to the baseline. Box 5 gives an example of a taxi driver's description of a route to take.


(Source: Washington irving; in public domain)

Figure 10 - Hippocampi in human brain.

Table 24 - Main areas of the brain activated by dif ferent tasks.

Box 5 - Example of taxi driver's description of rou te.

Task: Pick up on Grosvenor Square in Mayfair, drop off at Bank Underground Station, then at the OvalCricket Ground. "Grosvenor square, I’d leave that by Upper Grosvenor Street and turn left into Park Lane. I would eh enter Hyde Park Corner, a one-way system and turn second left into Constitution Hill. I’d enter Queen Victoria Memorial one-way system and eh leave by the Mall. Turn right Birdcage Walk, sorry right Horse Guards Parade, left Birdcage Walk, left forward Great George Street, forward into Parliament Square, forward Bridge Street. I would then go left into the eh the Victoria Embankment, forward the Victoria Embankment under the Blackfriars underpass and turn immediate left into Puddledock, right into Queen Victoria Street, left into Friday Street, right into Queen Victoria Street eh and drop the passenger at the Bank where I would then leave the Bank by Lombard Street, forward King William Street eh and forward London Bridge. I would cross the River Thames and London Bridge and go forward into Borough High Street. I would go down Borough High Street into Newington Causeway and then I would reach the Elephant and Castle where I would go around the one-way system” (Maguire et al 1997 p7106).

TASK MAIN BRAIN AREAS ACTIVE

Route Extrastriate regions; medial parietal lobe; posterior cingulate cortex; parahippocampal gyrus; right hippocampus

Landmarks Posterior cingulate cortex; medial parietal lobe; occipito-temporal regions

Film plots Left frontal regions; left middle temporal gyrus

Film frames Left frontal regions; right middle temporal gyrus


Maguire et al (1997) showed that the hippocamp us was more active in spatial memory tasks. Subsequently, MRI scans showed the structure of the hippocampus as different in London taxi drivers. Maguire et al (2000) compared sixteen experien ced male taxi drivers with 50 healthy (non-taxi driving ) controls. The taxi drivers had significantly differ ent hippocampi (right and left) than the controls, thou gh the overall volume was the same, and the brains showed no other differences. The difference was manifest as a larger posterior part and a smaller anterior part ( table 25). Furthermore, length of time spent as a taxi dr iver correlated with right posterior hippocampus size. Overall, this work showed that "mental maps" are st ored in the posterior hippocampus.

(All significant differences p<0.05 between taxi an d non-taxi drivers) (After Maguire et al 2000)

Table 25 - Size of areas of hippocampus (mm²). 7.3. NUCLEAR MAGNETIC RESONANCE IMAGING (NMRI or MRI) This technique, which entered clinical practic e in 1982 (Sadock and Sadock 2003), also shows the stati c brain, through the use of magnetic fields (figure 1 1). It works by measuring the hydrogen atoms in wa ter. The hydrogen nuclei are exposed to strong magnetic fields and line up like tiny magnets. Then they are hit wi th radio signals which causes them to move out of alig nment. This produces a signal that can be measured. Compared with CAT scans, MRI provides a better contrast between grey and white matter. The upshot of which is more anatomical detail (Johnstone 1993). This is no need for radioactive substance to b e injected, but there is concern about the effect of the strong magnetic field on the body. Manganese has been used recently to enhance br ain activity in MRI scans (manganese enhanced MRI; MEMR I), though in large doses it is toxic (Silva and Bock 2 008).

HIPPOCAMPUS TAXI DRIVERS NON-TAXI DRIVERS

Right - anterior - posterior

95 76

105 74

Left - anterior - posterior

80 75

100 70


(Source: NASA; in public domain; http://spaceresearch.nasa.gov/general_info/05feb_su perconductor.html )

Figure 11 - MRI scan of brain from side. Johnstone et al (1989) had three groups of participants receive MRI scans: 21 individuals with schizophrenia, 20 with bipolar disorder, and 21 con trols. The first group showed two brain structure differen ces compared to the others: larger temporal horns of th e lateral ventricles, and a reduction in the left tem poral lobe area. Thompson et al (2001) were able to produce 3D maps of the grey matter of the brain and the cortical su rface using high-resolution 3D MRI of forty healthy Finni sh adult twins. Identical twins were "almost perfectly correlated in their grey matter distribution". 7.4. MAGNETIC RESONANCE SPECTROSCOPY (MRS) MRS is based on the same principles as MRI, an d uses magnetic fields - unpaired photons and neutrons ali gned with a magnetic field. Radio frequency pulsing caus es nuclei to absorb and emit energy. This produces a spectrum of the brain's chemical compounds. There are different types of MRS: for example, observing the proton nucleus (1H) in the hydrogen a tom (H MRS), or the stable isotope of phosphorous (31P) (F rangou and Williams 1996). 7.5. FUNCTIONAL MAGNETIC RESONANCE IMAGING (fMRI) This technique detects tissue mass based on bl ood flow, by measuring changes in deoxyhaemoglobin when


neurons are active. Increased neural activity means a reduction in the concentration of deoxyhaemoglobin. In practice, it is possible to localise neuronal activ ity. It measures the "pooled neural responses acros s a voxel (a three-dimensional volume element analogous to a pixel in a two-dimensional digital image) or many v oxels that constitute a brain region" (Grill-Spector and Sayres 2008). Recent developments include fMRI-adaptation (f MRI-A), pattern analysis (PA), and high-resolution fMRI (H-fMRI)(Grill-Spector and Sayres 2008). There is no need for a radioactive tracer (Lid dle 1996). But acquisition of enough images for study c an require the participant's head to remain still in t he machine for up to three hours. Small changes in hea d position can lead to "erroneous interpretations" of brain activation (Sadock and Sadock 2003). The strong magnetic field has also been shown to slow down brain processes, even if it is not harmfu l (Foucher et al 2008). Brain activity in a female partner of a couple was examined with fMRI for "pain empathy" as the male p artner was seen to receive a painful electric shock to the hand. Certain areas (eg: rostral anterior cingulate corte x) were activated both when experiencing pain and when seeing partner experience pain. Seeing a loved one experience pain was not identical to experiencing p ain, but there were common patterns of brain activity (S inger 2004). 7.6. ETHICAL ISSUES AND NEUROIMAGING The technology of neuroimaging has implication s related to free will, agency, and personality among other things, and it requires an ethical awareness for th eir use by researchers. This ethical awareness has been called "neuroethics" (Marcus 2002). Fuchs (2006) distinguished two main areas of e thical concerns with neuroimaging: i) The "new methods and technologies, by layin g bare neural correlates of personal identity, cause probl ems of individual rights on privacy, non-interference and inviolability" (p600); ii) The findings are reductionist in that ever ything is reduced to neurons firing and electrochemical processes.


For example, Libet (1985) showed that electric al activity in the brain ("readiness potential") occur s 500ms before an individual consciously chooses to d o an action. Individuals, wired to EEG sensors, were tol d to pick up items when they wanted. If free will is not hing more than this, than is an individual ever truly responsible for their behaviour? Responsibility So many of the findings using neuroimaging que stions the responsibility of the individual for their beha viour. The assumption of biological determinism is implici t (and explicit) in the research. Adrian Raine (eg: Raine et al 1998), for examp le, using PET scans with convicted murderers, has found poor prefrontal cortex functioning compared to the gener al population. Relevant abilities in the prefrontal co rtex include controlling impulses, awareness of future consequences, and empathy which all discourage murd erous behaviour. The first thing is the distinguishing in terms of physiology between offenders and non-offenders. The prefrontal cortex can be damaged in subtle ways by childhood physical abuse and maltreatment (Teich er 2002). So the abuse leads to brain damage which lea ds to violence (directly or indirectly), can the perpetra tor be held responsible for their actions? If an individua l has no impulse control through damage to the prefrontal cortex, what is to stop them committing impulsive behaviour? Who is to blame when a car without brake s crashes? Knowing More Than the Individual Themselves Another issue is that the sophistication of th e technology has led to inferences about mental state s outside of conscious awareness. In other words, neuroimaging is telling us something that the indiv idual does not consciously know themselves. The idea of t he "transparent brain" (Fuchs 2006). One example of this is unconscious attitudes. The idea that there is a conscious attitude (what the individual reports on attitude questionnaires) and an unconscious attitude (what they really believe). Th e two may, of course, be in agreement. But more interesti ng when they are not, as in the case of racial attitud es. For example, white participants who did not re port racist attitudes, showed greater activity in the am ygdala in response to black people's faces than whites (Ph elps et al 2000). This would suggest fear of these faces , and


the inference of unconscious racist attitudes. More than this, inferences are made about futu re behaviour. For example, Arnow et al (2002) showed a link between particular sexual preferences and physiolog ical correlates in "healthy heterosexual men". In other words, if a non-offender shows the physiological correlate s associated with sexual violence in an experiment, t he prediction could be made that such an individual wi ll perpetrate sexual violence in the future. But shoul d it be made in terms of labelling individuals before th ey offend? If it is possible to know more from brain scan s than the individual knows themselves, it could be inferr ed if they are lying. "Brain fingerprinting" is based on this assumption. Developed by Lawrence Farwell (Farwell and Smith 2001), it measures P300 waves by EEG in respo nse to knowledge of facts about a crime. The P300 wave response to crime-related words flashed on a screen are classed as "guilty knowledg e" which the offender cannot hide. The key is that the re will be information that is only known to the offen der and the "guilty knowledge test" will find it among hundreds of questions asked. The technology is bein g used in the US legal system (eg: murder conviction rever sal in Iowa; Fuchs 2006). One major problem stands out with "brain fingerprinting". It measures recognition, and this recognition may be from elsewhere than the "guilty knowledge" of the offender (Innovation 2004). Neuroimaging has also been used to detect dece ption by showing the physiological correlates of intentio nal deception (eg: in anterior cingulate cortex in func tional magnetic resonance imaging; Langleben et al 2002). The faith in what scanning is able to tell us about the "real" or "secret" thoughts of the individual i s highlighted in a system called MALINTENT (Future Attribute Screening Technology - FAST). It is a "bo dy scanner" developed in the USA to detect terrorists in advance of an attack, for example, using measures o f body temperature, heart rate, and respiration, and micro -facial scanning (minute muscle movements in faces). "It is like an X-ray for bad intentions" (Barrie 2008). Wider Ethical Issues with Neuroimaging There are a number of critical issues in using neuroimaging, particularly when it goes beyond the simple description of physiology.


1. The gap between subjective experience and electromagnetic signals. "Imaging studies are based on probabilistic covariances and not on causal connections. Their interpretation depends on the design and theory beh ind the study.." (Fuchs 2006 p601). It is one thing to see the brain activated dur ing certain behaviour, and another to say what is actua lly going on, particularly in terms of subjective exper ience. This is even more so with complex social issues - e g: showing a reaction in the amygdala to a photograph flashed on a screen briefly is a very poor way of measuring racial attitudes. Attitudes, at least, in volve different components - cognitive, affective, and behavioural (Secord and Backman 1964). If neuroscience comes to dominate in psychiatr y, as in cognitive neuropsychiatry (CNP) (Halligan and Da vid 2001), then diagnosis of mental disorders will depe nd on neuroimaging techniques. Such an approach would lea d to changes in the clustering of symptoms, and the elimination of classifications like "schizophrenia" , "bipolar disorder" etc. They will be replaced by "neurological explana tions and to the entities that make up such explanations instead" (Fuser-Poli and Broome 2006 p610). So at the moment, depression would be diagnose d based on the presence of behavioural symptoms like low mood and suicidal thoughts, diagnosis in CNP would revolve around brain abnormalities. Depression woul d equal the specified abnormalities in the particular areas of the brain. Behavioural symptoms would simply be a product of these brain abnormalities. The mind, as in subjective experience, is removed from the process. This has been called "eliminative mindless psychiatry" (Jablensky and Kendell 2002). 2. From potential to actual. It is one thing to say that the individual has the physiology for potential violence and another for t hem to show it. There are many factors between the potenti al and actual. Brewer (2003) distinguished three groups of fa ctors (individual, group and social) that lead to a gener al level of aggression, but then disinhibitions and environmental triggers that explain the specific aggression shown. This move from general to specifi c is similar to the move from potential to actual. There are a lot of concerns if individuals are


punished for having the potential to be dangerous. Though we live in a society that is trying to pursue such ideas. The ability to predict future behaviour is the holy grail of psychology and psychiatry. Sometimes it is done well, many other times done badly. "The wide-spread misunderstanding of brain sca ns as direct measures of psychological states or even tra its, however, carries the risk that courts, parole board s, immigration services, insurance companies and other s will use these technologies prematurely" (Fuchs 2006 p60 1). 3. Acting on the knowledge. In the area of mental illness, studies have lo oked for pre-onset factors to predict the mental disorde rs. For example, functional magnetic resonance scans of adolescents with a high family risk of schizophreni a show brain differences (eg: Pantelis et al 2003). To act upon this knowledge could mean giving t hese adolescents anti-psychotic drugs before any behavio ural symptoms have appeared. Such drugs have effects on the brain as well as producing side-effects. How long t o remain on the medication? Not to mention the potent ial for discrimination from others, and the effects of the knowledge on the individual's self-esteem (Fuchs 20 06). 4. Technology as threatening. "Our sense of privacy may be threatened by technologies that can reveal the neural correlates of our innermost thoughts and unconscious attitudes" (Fuch s 2006 pp601-602). At the moment, such technology is relatively l imited in this, but what if it becomes more reliable and accurate in the future. This is a threat to "cognit ive liberty" - an individual's right over their own bra in and its contents (Sententia 2004).


8. NEW AND MISCELLANEOUS TECHNIQUES 1. Computer Modelling Neural networks can be used to model human cognition, and then parts "turned off" to show the effect of brain damage (Mayall 1998). 2. Transgenic and Knockout Animals Modern genetic engineering allows for animals to be "produced" which lack a gene of interest ("knockout ") or have a gene from a human, say (transgenic). For exa mple, knockout mice have been engineered that cannot prod uce the neurotransmitter, orexin (Siegel et al 2001). 3. Reverse Engineering This involves speculating about the function o f a behaviour in the evolutionary past from its current existence (Tooby and Cosmides 1992). 4. Thought Experiments These are philosophical puzzles that help researchers to think about the issues in consciousn ess. For example, in the "zombie thought experiment", a molecule by molecule replica of a conscious human b eing is made. Is this replica ("zombie") conscious? How this question is answered links to the view taken about consciousness (Braisby 2002).


9. ISSUES AND DEBATES 9.1. MIND-BRAIN RELATIONSHIP The focus is upon how to study the brain (the physical organ), but what is its relationship with the mind or consciousness (the subjective experience). Rene D ēscartes, in the seventeenth century, distinguished between the mind and the body in an i dea now called dualism. The body was described as a "ma chine" while the mind (or soul) is non-material and locate d in the pineal gland. This established the principle of the mind and the brain/body as different. Dualism would mean that the mind could exist in the absence of the bod y (Toates 2004). The alternative to dualism is monism, which se es the mind and brain as one. There are also theories whic h attempt to reject both monism and dualism. Searle (1999) distinguished two types of duali sm in philosophical terms: � Substance dualism - the universe is divided into

material objects and immaterial minds; � Property dualism - there are physical properties (e g:

how much an object weighs) and mental properties (e g: subjective experience).

In each case, the two elements are mutually exclusive. The different relationships between the mind a nd the brain can be summarised thus (Gross 1992): 1. Dualism: The mind and body/brain are causally re lated. i) Interactionism There is a two-way relationship between the mi nd and the body/brain. The mind can influence the body/bra in as in psychosomatic illness or the placebo effect, whi le the body/brain can influence the mind (eg: drugs that c hange perception or brain damage changing personality). Strength - Fits well with common sense. Weakness - How do they actually influence each othe r? ii) Epiphenomenalism The causal relationship is only in one directi on (ie: the physical influences the mental). In fact, mental


experiences are by-products of physical processes. The mind or consciousness is "just a kind of vaporous residue cast off by the brain, but is unab le to do anything on its own" (Searle 1999 p58). Strength - Concentrates upon the brain which can be seen and studied. Weakness - Does not explain how mental processes ar e a by-product of physical processes. 2. Dualism: The mind and body/brain are correlated but causally independent. Psychophysical Parallelism Originally proposed by Leibniz in the eighteen th century, mental and physical processes occur simultaneously but independent of each other (ie: n ot causing one another). For example, the mental exper ience of perceiving an object occurs at the same time as the physical processes involved (neurons firing in diff erent parts of the brain). Strength - Allows for both the mind and the body to be studied separately. Weakness - Often there is no simple correlation bet ween a physical and a mental process. For example, the men tal experience of depression can occur in response to different physical states or processes. 3. Dualism: The mind and body unrelated. 4. Monism: The mind and the brain are the same. i) Idealism/Mentalism Based on the original idea of George Berkeley, in the nineteenth century, only mental processes are r eal. This idea saw the mind as only existing and the bra in exists as ideas in that mind. "Transcendental idealism", from Immanuel Kant, "maintains that the fundamental categories in terms of which we characterise the world are not objective features of things in themselves but are structures imposed by the mind; without such organising struct ures experience would not be possible" (Haugeland 1987 p 337). Strength - "Transcendental idealism" emphasises how


structures of the mind (meanings) make sense of the physical world. Weakness - Idealism seems to be anti-common sense. ii) Materialism (or physicalism) Only physical processes are real. In other wor ds, the mind is the product of the brain: cells firing in a certain way produces the experience of consciousnes s (eg Dennett). Strength - It is a view held by many scientific psychologists, and it holds out hope of finding the physical basis to all experiences. Weakness - Reductionist: subjective experience is r educed to physiology. iii) Identity Theory This is a recent development of Materialism wh ich emphasises that consciousness is a brain process. T hey are the same thing, but have different meanings, li ke the words, "sister" and "female sibling". The two words describe the same person, but the meaning of each i s different. So the language is important. Strength - As Materialism. Weakness - As Materialism. iv) Panprotopsychic Identism (or Panpsychism) This is the view that consciousness exists in all matter, and that "all physical things have a mental side, aspect, or properties, even if in a primitive and undeveloped form" (Armstrong 1987 p491). Strength - Offers a "spiritual" view to counter Materialism. Weakness - Difficult to study scientifically. 5. Alternatives to Monism and Dualism. i) Double-aspect theory (Valentine 1982) Both the mind and the brain are real, but they are


aspects of a "fundamental underlying reality". Strength - Tries to break out of the monism-dualism dichotomy. Weakness - Not clear what the "fundamental underlyi ng reality" is. ii) Naturalistic Functionalism Developed by William James, consciousness ("Conscious Mental Life") has evolved via natural selection among species with a certain type of brai n. Consciousness (the mind) is an "emergent property" of the physical brain, but, at the same time, distinct fro m it. Strength - Explains the development of the mind thr ough the theory of evolution. Weakness - How is the mind both a product of and di stinct from the brain? iii) Computational Theory of the Mind This is a recent development of the last view, and uses the computer analogy of software/hardware. The brain is the hardwire and the mind is the software. Strength - Gives a basis for developing computer mo dels of the mind and brain. Weakness - Reductionist: the computer analogy is limiting. 9.2. CONSCIOUS AND NOT CONSCIOUS There is the conscious part of the mind, and t he other part. This other part can be called "not- conscious", though many other terms have been used like unconscious, sub-conscious, or pre-conscious. Work on the physiology of the brain in recent years has played down the importance of the conscious par t as seen in this quote: "the normal unconscious brain monitors the mirror for cues that prompt it to deci de whether to awaken and engage.. The decision to enga ge at all is, in effect, an unconscious decision to be conscious" (Michael Shadlen quoted in Douglas 2007) . Here are some categories of conscious and not-conscious. It is an attempt to clarify the differen t


ideas rather than being exhaustive. 1. Conscious The part of the mind that the individual is fu lly aware of. Early psychology focused on conscious tho ught through introspection, while con awareness is key t o humanistic and experiential psychology (Stevens 199 6). 2. Unconscious Sigmund Freud (1923/1991) saw the majority of the mind as inaccessible to consciousness, but still determining behaviour. It is the originator of the "real" motive for behaviour rather than the conscious (ill usory) explanation given. Technically, it is known as the "dynamic unconscious". 3. Pre-conscious This is the part of the mind that the individu al can become aware of when required. For example, the rec all of stored memories. Memories are not conscious until recalled. 4. Outside consciousness This category is used to cover automatic physiological processes that individuals have no conscious control over (eg: breathing, digestion). These processes continue irrelevant of the individual's conscious state, like during sleep. 5. Automatic behaviours Learned behaviours or skills can be performed without conscious attention, and in well practised cases, do better without conscious thought. It is possible to focus consciously upon them if necessary. 6. Non-conscious This category is the most challenging to the understanding of the conscious self. It is the situ ation where physiological measures show brain activity, b ut the individual reports no conscious awareness (eg: subl iminal perception).


For example, in the case of blindsight, indivi duals with damage to the visual cortex report blindness, but when asked to guess a position of an object in thei r blindfield do so correctly. It is almost an "uncons cious seeing and a conscious blindness". 7. Unawareness This category is included to cover lack of ins ight and not noticing things. For example, individuals m ay not be aware of the effect of their behaviour on others , but they can be made aware by others telling them or by self-reflection. This can be called "consciousness-raisi ng". Non-Conscious Non-conscious brain activity is studied by fla shing a stimulus on a screen for a very short time. Indiv iduals fail to report seeing anything if the duration is l ess than 50ms, but the brain registers the stimulus eve n when not consciously seen (as measured by electrical activity)(eg: Del Cul et al 2007). The question is whether the conscious/non-cons cious are parts of the same system or separate systems. I n the case of the latter, for example, Daw et al (2005) h ave described four systems (two conscious and two non-conscious)(Douglas 2007): � Pavlovian controller (non-conscious) - controls

routine, reflexive, and instinctive behaviour; � Habitual controller (non-conscious) - controls

habitual, learned behaviour like driving; � Episodic controller (conscious) - in control in

unfamiliar situations, and when learning is new; � Goal-directed controller (conscious) - rational

decision-making. In Halligan and Oakley's (2000) two-level mode l, most cognitive processes occurs at level 2 (non-conscious), which includes the central executive sy stem (CES). Level 1 is conscious awareness and voluntary control. The CES creates the belief in the self, an d maintains a consistent self and a biography along w ith the illusion of control 10.

10 Another debate relates as to whether we have free will and conscious control over our behaviour .


Non-Conscious Decision-Making The declining importance of conscious thought includes the case of making decisions. " An example of unconscious thought is the following: One compares two holiday destinations (say the Costa Brava and Tusca ny) and does not know what to decide. One puts the prob lem aside and after 48 hours of not thinking about it consciously, suddenly the thought 'It's going to be Tuscany!' pops into consciousness. This thought itself is conscious, but the transition from indecision to a preference 2 days later is the result of unconscious thought, or of deliberation without attention" (Dijksterhuis et al 2006 p1005). Dijksterhuis et al (2006) have called this the "deliberation-without-attention" effect. They argue that conscious thought is better for simple decisions, b ut unconscious decisions are better with complex choic es. This was formalised in the "unconscious thought the ory" (UTT)(Dijksterhuis and Nordgren 2006). Basically unconscious thought is able to find patterns which conscious thought can do because the latter is "rul e-based and very precise". Dijksterhuis et al (2006) offered participants a choice of four cars based on a series of attributes . In the simple decision, there were four attributes, an d twelve with the complex decision. The attributes we re positive or negative, and altered for each car - on e car 75% positive/25% negative, 50%/50% for two cars, an d one car 25% positive/75% negative. One group were asked to think carefully for fo ur minutes about their decision (conscious decision-ma king) while the other group had to solve anagrams as a distraction task for four minutes (unconscious deci sion-making). The latter group made the better choice fo r the complex decision, and the simple decision was bette r in the conscious decision-making group (table 26).

(After Dijksterhuis et al 2006)

Table 26 - Percentage of participants who chose mos t desirable car. Dijksterhuis et al (2006) performed three othe r

SIMPLE DECISION COMPLEX DECISION

CONSCIOUS DECISION-MAKING 55 20

UNCONSCIOUS DECISION-MAKING

40 60


experiments about choices of consumer goods and fou nd the same principle. They concluded: Although we investigated choices among consumer products in our studies, there is no a priori reason to assume that the deliberation - without-attention effect does not generalize to other types of choices—political, managerial, or otherwise. In such cases, it should benefi t the individual to think consciously about simple matters and to delegate thinking about more complex matters to the unconscious (p100 7). Lassiter et al (2009) replicated the complex decisions in the experiment, but added conditions w hich asked participants (university students) to memoris e the cars' attributes as well. In this case, the conscio us decision-making group did better (table 27).

(Higher score = better decision) (After Lassiter et al 2009)

Table 27 - Mean preferences for car with most posit ive attributes. This work challenges that of Dijksterhius et a l, but it does not necessarily support conscious decision-making. For the researchers the decision is made on "an immediate gut instinct" (Schultz 2009). This is supported by Cleeremans (quoted in Sch ultz 2009) who used a similar experiment to test decisio n-making on apartments based on a series of attribute s. Decisions made immediately were as good as those ma de by the unconscious decision-making group. Central Executive Another question related to consciousness is w hether the brain has a central place or executive that con trols its activities. The common sense belief and historical view is that there is a central executive in the brain. This is sometimes called the "Cartesian theatre", where consciousness lives and is controlled. Descartes be lieved

THINK CAREFULLY SOLVE ANAGRAMS

DIJKSTERHUIS ET AL REPLICATION

0.80 1.78

MEMORISE ATTRIBUTES 1.95 0.92


that the brain had a centre, which he said was the pineal gland. Also early theories of the brain believed that a "little man" (homunculus) sat inside and controlled everything that happened (Dennett 1991). In terms of cognitive processes, Norman and Sh allice (1986) developed the idea of a central executive th at controlled attention, memory, and willed actions 11. Modern theories of the brain tend to reject th e idea of such a place in the brain. "Rather than a centra l executive, there seems to be a network of brain reg ions that organise the resting state and maintain overal l orientation towards context" (Shadlen and Kiani 200 7). Neuroimaging scans during performance of atten tion-demanding cognitive tasks produced two patterns of brain activity - increased activity in frontal and pariet al cortical regions and reduced activity in other area s including the medial prefrontal cortex (Fox et al 2 005). This supports the notion of opposing or competing processes in the brain, which is popular in a numbe r of recent theories (Blackmore 2002). Dosenbach et al (2007) confirmed the idea of t o distinct "task-control networks" in the brain - the fronto-parietal network and the cingulo-opercular network. The feeling that we have that there is a contr ol place in the brain where we "live" is an illusion c reated by the brain (Blackmore 2002).

11 Some implicit processing produces prefrontal cortex activity similar to explicit processing/conscious awareness (Badgaiyan 2000).


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11. APPENDIX

(Source: In public domain)

Figure A - Paul Broca.

(Source: McGill University Archive; out of copyrigh t; in public domain)

Figure B - Wilder Penfield.

methods and issues of studying the brain in psychology

Documents

brain injurydamage

introductionthe brain

brain damage

destruction of brain

psychology kevin brewer

brain lesions example

split brain patients

mindbrain relationship