fem 4100 brain & human behavior topic 1: introduction

FEM 4100 Brain & human Behavior

Topic 1: Introduction

True or False?

Do we use only 10% of our Do we use only 10% of our brains?brains?

False: False: There is no scientific There is no scientific evidence to suggest that we use evidence to suggest that we use only 10% of our brains.only 10% of our brains.

Where Did the 10% Myth Begin?

The 10% statement may have been started with a misquote of Albert Einstein or the misinterpretation of the work of Pierre Flourens in the 1800s.

It may have been William James who wrote in 1908: "We are making use of only a small part of our possible mental and physical resources" (from The Energies of Men, p. 12).

Where Did the 10% Myth Begin? Perhaps it was the work of Karl Lashley in the

1920s and 1930s that started it. Lashley removed large areas of the cerebral cortex in rats and found that these animals could still relearn specific tasks.

We now know that destruction of even small areas of the human brain can have devastating effects on behavior.

That is one reason why neurosurgeons must carefully map the brain before removing brain tissue during operations for epilepsy or brain tumors: they want to make sure that essential areas of the brain are not damaged.

Why Does the Myth Continue? Somehow, somewhere, someone started this

myth and the popular media keep on repeating this false statement (see the figures). Soon, everyone believes the statement regardless of the evidence. I have not been able to track down the exact source of this myth, and I have never seen any scientific data to support it.

According to the believers of this myth, if we used more of our brain, then we could perform super memory feats and have other fantastic mental abilities - maybe we could even move objects with a single thought. Again, I do not know of any data that would support any of this.

What Does it Mean to Use Only 10% of Your Brain? What data were used to come

up with the number - 10%? Does this mean that you would

be just fine if 90% of your brain was removed?

If the average human brain weighs 1,400 grams (about 3 lb) and 90% of it was removed, that would leave 140 grams (about 0.3 lb) of brain tissue.

That's about the size of a sheep's brain.

What Does it Mean to Use Only 10% of Your Brain? It is well known that damage to a relatively

small area of the brain, such as that caused by a stroke, may cause devastating disabilities.

Certain neurological disorders, such as Parkinson's Disease, also affect only specific areas of the brain.

The damage caused by these conditions is far less than damage to 90% of the brain.

What Does it Mean to Use Only 10% of Your Brain? Perhaps when people use the 10% brain

statement, they mean that only one out of every ten nerve cells is essential or used at any one time?

How would such a measurement be made? Even if neurons are not firing action

potentials, they may still be receiving signals from other neurons.

True or False?

Your brain makes a painkiller Your brain makes a painkiller similar to heroinsimilar to heroin

True: Naturally produced chemicals True: Naturally produced chemicals called called endorphinsendorphins are closely related are closely related to herointo heroin

True or False? Is Laughter the Best Medicine?Is Laughter the Best Medicine?

True: True: It may be a good way for people to relax because muscle tension is reduced after laughing.

• There are some cases when a good deep laugh may help people with respiratory problems by clearing mucus and aiding ventiliation.

• Perhaps laughing can also help cardiac patients by giving the heart a bit of a workout.

• Some hospitals even have their own "Humor Rooms," "Comedy Carts," and clown kids in attempts to speed a patient's recovery and boost morale.

False: False: However, laughter is NOT However, laughter is NOT ALWAYS good medicine. ALWAYS good medicine.

• There are a few cases when laughing There are a few cases when laughing actually CAUSED a heart attack or a actually CAUSED a heart attack or a stroke. stroke.

• Also, immediately after abdominal Also, immediately after abdominal surgery, people should not laugh too surgery, people should not laugh too hard because they could tear out their hard because they could tear out their stitches accidentally. stitches accidentally.

• Care should also be used in patients Care should also be used in patients with broken ribs. So, try not to be too with broken ribs. So, try not to be too funny around these people.funny around these people.

• Research has shown that parts of the limbic system are involved in laughter.

• The limbic system is a primitive part of the brain that is involved in emotions and helps us with basic functions necessary for survival.

• Two structures in the limbic system have been shown to play a role in laughter: the amygdala and the hippocampus.

• Humans may be "tuned" for laughter much in the same way that songbirds are "tuned" for song -- especially their own specific family song. (While birdsong of one species may sound the same to you and me, there are subtle differences among the birds' songs.)

• Certain nerve cells in the songbird's brain "fire" in response to hearing his song.

• Perhaps humans have specialized nerve cells that respond to laughter.

• After all, laughter is a specialized vocalization, and we are "tuned" to respond to vocalizations with language.

• We use our brain for many things. • Laughter is yet another part of human behavior that

the brain regulates. • It helps us clarify our intentions and provides an

emotional context to our conversations. • Laughter, then, is used as a signal for being part of a

group--it signals acceptance and positive interactions. • It clues the listener in to the emotional tone of the

conversation and the speaker's intentions. • This may be one reason it is more difficult to interpret

the meaning of an e-mail or letter--emotional clues about the sender's tone are missing.

Laughter Laughter isis contagious. contagious. Since 1950, TV has exploited this by adding Since 1950, TV has exploited this by adding

"laugh tracks" to sitcoms. "laugh tracks" to sitcoms. People laugh more readily upon hearing People laugh more readily upon hearing

others laugh. others laugh. When you hear others laugh, you actually When you hear others laugh, you actually

think the TV show is more humorous. think the TV show is more humorous. Babies start to laugh at about 4 months of Babies start to laugh at about 4 months of

age. age. Babies who are born blind and deaf can laugh, Babies who are born blind and deaf can laugh,

so the ability to see or hear is not required for so the ability to see or hear is not required for laughter.laughter.

Did You Know?Did You Know?

Many things that happen to us Many things that happen to us leave no record in memoryleave no record in memory

True or False?True or False?

True: Most of the information around True: Most of the information around us never reaches memory, and what us never reaches memory, and what does reach memory often gets does reach memory often gets distorteddistorted

You are born with all the brain You are born with all the brain cells you will ever havecells you will ever have


False: Recent research shows that False: Recent research shows that some parts of the brain continue some parts of the brain continue producing new cells throughout lifeproducing new cells throughout life

How does the brain compare to How does the brain compare to the computer??the computer??

The Brain vs. The ComputerThe Brain vs. The Computer

• Some people say that the computer is better Some people say that the computer is better than the brain; some people say that the than the brain; some people say that the brain is better than the computer. brain is better than the computer.

• Perhaps, it is best to say that the brain is Perhaps, it is best to say that the brain is better at doing some jobs and the computer better at doing some jobs and the computer is better at doing other jobs.is better at doing other jobs.

The Brain vs. The ComputerThe Brain vs. The Computer

Similarity Both use electrical signals. Difference The brain uses chemicals to

transmit information; the computer uses electricity. Even though electrical signals travel at high speeds in the nervous system, they travel even faster through the wires in a computer.

The Brain vs. The ComputerThe Brain vs. The Computer Similarity Both transmit information. Difference A computer uses switches that are either

on or off ("binary"). In a way, neurons in the brain are either on or off by either firing an action potential or not firing an action potential. However, neurons are more than just on or off because the "excitability" of a neuron is always changing. This is because a neuron is constantly getting information from other cells through synaptic contacts. Information traveling across a synapse does NOT always result in a action potential. Rather, this information alters the chance that an action potential will be produced by raising or lowering the threshold of the neuron.

The Brain vs. The ComputerThe Brain vs. The Computer Similarity Both have a memory that can grow. Difference Computer memory grows by adding

computer chips. Memories in the brain grow by stronger synaptic connections.

The Brain vs. The ComputerThe Brain vs. The Computer Similarity Both can adapt and learn. Difference It is much easier and faster for the brain

to learn new things. Yet, the computer can do many complex tasks at the same time ("multitasking") that are difficult for the brain. For example, try counting backwards and multiplying 2 numbers at the same time. However, the brain also does some multitasking using the autonomic nervous system. For example, the brain controls breathing, heart rate and blood pressure at the same time it performs a mental task.

The Brain vs. The ComputerThe Brain vs. The Computer Similarity Both need energy. Difference The brain needs nutrients like oxygen and

sugar for power; the computer needs electricity to keep working.

Similarity Both can be damaged. Difference It is easier to fix a computer - just get new

parts. There are no new or used parts for the brain. However, some work is being done with transplantation of nerve cells for certain neurological disorders such as Parkinson's disease. Both a computer and a brain can get "sick" - a computer can get a "virus" and there are many diseases that affect the brain. The brain has "built-in back up systems" in some cases. If one pathway in the brain is damaged, there is often another pathway that will take over this function of the damaged pathway.


Both center patches are the same shade of gray

True: The patch on the right appeared darker due to perceptual contrast with its background

Intelligence is a purely genetic Intelligence is a purely genetic trait that does not change trait that does not change throughout a person’s lifethroughout a person’s life


False: Intelligence is the result of both False: Intelligence is the result of both heredity and environment, and may heredity and environment, and may change throughout your lifechange throughout your life

Repeated exposure to the same Repeated exposure to the same face leads us to like it lessface leads us to like it less

False: Familiar people (and their False: Familiar people (and their faces) are generally liked more than faces) are generally liked more than less familiar people less familiar people


Four Major Themes

Why study the brain? History of brain study Disciplines of neuroscience (study of

the brain) Clinical implications

Why study the brain?

“The more you use your brain, the more brain you will have to use.”George A. Dorsey

“Brain: an apparatus with which we think we think.”Ambrose Bierce

Why study the brain?

The human brain is packed solid with billions of nerve cells each communicating with thousands of preselected listeners over miles and miles of living wires (the nervous system) which operates the whole body

History of brain study

WHAT IS THE

BRAIN??

Analysis by analogy Explore the mind

problem The roots of dualism The pneuma theory Descardes & the brain

The scientific method The rise of

experimentation in psychology

Exploring the nervous system

Brain-behavior relation

Analysis by analogy

The ancient wondered – why can a thought / an emotion be experienced but not seen or touched

Found that inanimate was attributable to a spirit of vital force that could be neither seen or understood (known as animism today)

People view themselves in the dualistic term, with mind traditionally seen as an entity distinct from the physical world of matter and governed by entirely separate sets of principles

Roots of dualisme – writing of the Greek philosopher Anaxagoras

Plato elaborate on the concept, maintaining that the mind, or soul – the instrument with which knowledge is pursued – superior to the physical body & sense

Analysis by analogy The Pneuma Theory

Aristotle explained various animal functions, including movement, as being the result of "pneuma," a spiritual breath (literally) that was carried to the various organs to activate them, and that caused the limbs to move

The theory which attributed the functions of mind to invisible spirits, emerged during the rise of Greek civilization

Hippocrates (5 century, B.C.) theorized that the brain was the controlling mechanism of all mental & emotional faculties

Galen, Greek physician (129–201 A.D.) recognized that muscles were responsible for movement in both humans

and animals suggested that the inability to vocalize is a proof of the relationship

between the nervous system & behavior (based on research on a pig’s larynx)

Analysis by analogyThe Pneuma Theory

Leonardo da Vinci (1452–1519) discarded Aristotle's pneuma theory of motive force; he clearly understood that muscles were activated by nerves that ramified through them and caused them to contract, pulling the tendons and attached bones

Luigi Galvani, Italian physician (1790) – discovered that electric current applied to the muscle of a frog produce muscle movement, correctly theorized that the nerves are capable of conducting electricity (identified that the nature of pneuma was a unique substances he called animal electricity)

Analysis by analogyRene Descartes (1596-1650) & the

brain Rejected the Greek notion that

human fate is subject to the whim of invisible & unknowable force

Theorize that many behaviors formerly thought to be beyond the scope of conventional scientific investigation

eg. Basic sensory experiences – could be explained mechanistically, the same way you might explain the working of a complicated machine

What is the effect of Descartes thoughts on British empirism – John Locke, David Hume, etc??

Evolution of The Scientific Method

Behaviorism (John Watson) Structuralism (Wundt)

Identify the building blocks of consciousnessUsed introspection

Functionalism (James) Identify the ways the mind adapts to the world Influenced by Darwin’s ideas

Gestalt psychology (Wertheimer)The whole is greater than the sum of its parts

Evolution of The Scientific Method

Psychodynamic theory (Freud)We are influenced by the unconscious mindWe may try to suppress urgesPsychoanalysis

Disciplines of Neuroscience Neuroanatomy

Structure of the nervous system Neurochemistry

Chemical bases of neural activity Neuroendocrinology

Interactions between the nervous system and the endocrine system

NeuropathologyNervous system disorders

NeuropharmacologyEffects of drugs on neural activity

Disciplines of Neuroscience Neurophysiology

Functions and activities of the nervous system Neuroscience

Interdisciplinary field that focuses on the brain and its role in psychological processes

BiopsychologyThe specialty in psychology that studies the

interaction of biology, behavior, and the environment

Physiological Physiology Understanding the human consciousness

What is Biopsychology?

“the scientific study of the biology of behavior”

psychobiology, behavioral biology, behavioral neuroscience

psychology: the scientific study of behavior Hebb (1949) proposed that psychological

phenomena might be produced by brain activity

Biopsychology is an integrative discipline Knowledge from other disciplines of

neuroscience is applied to the study of behavior

Each discipline studies a different aspect of the nervous system that informs our understanding of what produces and controls behavior

Biopsychological Research

Human and nonhuman subjects

Experiments and nonexperiments

Pure and applied research

Human and nonhuman subjects

Why use nonhumans? Simpler brains makes it more likely that

brain-behavior interactions will be revealed Comparative approach – gain insight by

making comparisons with other species Fewer ethical restrictions

Divisions of Biopsychology

Six major divisions Each has a different approach, but there is

much overlap Physiological psychology,

psychopharmacology, neuropsychology, psychophysiology, cognitive neuroscience, comparative psychology


Physiological psychologyNeural mechanisms of behaviorDirect manipulation of the brain

PsychopharmacologyEffects of drugs on the brain

NeuropsychologyBrain damage in humans


PsychophysiologyRelation between physiological activity and

psychological processes Cognitive neuroscience

Neural bases of cognition Comparative psychology

Comparing different species to understand evolution, genetics, and adaptiveness of behavior

Figure 1.6 (summary)

Converging Operations: revelations from brain damages Using multiple approaches to address a

single question Korsakoff’s syndrome – a condition

characterized by severe memory loss and most commonly seen in alcoholics

Is Korsakoff’s the result of the toxic effects of alcohol on the brain?

Converging Operations

Jimmie G. – an alcoholic with Korsakoff’s Korsakoff’s is also seen in malnourished

persons who had little or no alcohol Thiamine-deficient rats exhibit memory

deficits Alcohol accelerates the development of

brain-damage in thiamine-deficient rats

Converging Operations

By exploring the possible causes of Korsakoff’s using multiple approaches, converging operations, findings are more accurate

Korsakoff’s syndrome is the result of thiamine deficiency, but the damage is accelerated by alcohol

Scientific Inference

The empirical method that biopsychologists use to study the unobservable

Scientists measure what they can observe and use these measures as a basis for inferring what they can’t observe

Critical Thinking

The ability to evaluate scientific claims by identifying potential omissions or weaknesses in the evidence

Morgan’s Canon – when several explanations are possible, give precedence to the simplest one

At what level of analysis would it be easiest to gain the best insight into Tiger Woods’ success?

A. Level of the brainB. Level of the personC. Level of the groupD. All three levels would need to

be analyzed.

Levels of Analysis

The brain

The person

The group

The Nature of Physiological Psychology

Generalization A type of scientific explanation; a general

conclusion based on many observations of similar phenomena.

Reduction A type of scientific explanation; a

phenomena is described in terms of the more elementary processes that underlie it.

The Nature of Physiological PsychologyBiological roots of physiological

psychologyReflex

An automatic, stereotyped movement produced as the direct result of a stimulus.

Model A mathematical or physical analogy for a

physiological process; for example, computers have been used as models for various functions of the brain.

Understanding Human Consciousness

Corpus callosum The largest commissure of the brain;

interconnecting the areas of the neocortex on each side of the brain.

Split-brain operation Brain surgery that is occasionally performed

to treat a form of epilepsy; the surgeon cuts the corpus callosum, which connects the two hemispheres.

Understanding Human Consciousness

Cerebral hemispheres The two symmetrical halves of the brain;

constitute the major part of the brain.


Biological roots of physiological psychology

Doctrine of specific nerve energies Muller’s conclusion that because all nerve fibers

carry the same type of message, sensoryinformation must be specified by the particularnerve fibers that are active.


Biological roots of physiological psychology

Experimental ablation The research method in which the function

of a part of the brain is inferred by observing thebehaviors an animal can no longer perform afterthat part of the brain is damaged.

Natural Selection and EvolutionFunctionalism and the inheritance of

traitsFunctionalism

The principle that the best way to understand a biological phenomenon (a behavior or a physiological process) is to try to understand its useful functions for the organism.

Natural selection The process by which inherited traits that confer

a selective advantage (increase an animal’s

likelihood to live and reproduce) become more

prevalent in a population.

Functionalism and the inheritance of traits Mutation

• A change in the genetic information contained in• the chromosomes of sperm or eggs which can

be• passed on to an organism’s offspring; provides• genetic variability.

Selective advantage• A characteristic of an organism that permits it to• produce more than the average number of

offspring• of its species.

Evolution has fundamentally shaped psychological

processes because it favors genetic variations that

produce adaptive behavior

How Are Genes and Behavior Linked?

How Are Genes and Behavior Linked?

Innate – Inborn; present at birth; part of the organism’s biological heritage

Evolution –The gradual process of biological change that occurs in a species as it adapts to its environment

Natural selection –The driving force behind evolution, by which the environment “selects” the fittest organisms

How Natural Selection Works

Environmental pressureEnvironmental pressure(changes in the environment)(changes in the environment)

CompetitionCompetition(for resources)(for resources)

Selection of fittest phenotypeSelection of fittest phenotype(from among a variety of phenotypes)(from among a variety of phenotypes)

Reproductive successReproductive success(genotype corresponding to fittest (genotype corresponding to fittest

phenotypes passed to next generation)phenotypes passed to next generation)

Frequency of that genotype increasesFrequency of that genotype increases(in next generation)(in next generation)

Natural Selection and EvolutionEvolution of the human speciesEvolution

A gradual change in the structure and physiology

of a plant and animal species, generally producing more complex organisms, as a result of natural selection.

Natural Selection and Evolution

Evolution of the human species

Evolution A gradual change in the structure and physiology

of a plant and animal species, generally producing

more complex organisms, as a result of natural

selection.

The Nature of Physiological PsychologyEvolution of large brainsNeoteny

A slowing of the process of maturation, allowing more time for growth; an important factor in the development of large brains.


Evolution of large brains

Neoteny A slowing of the process of maturation, allowing

moretime for growth; an important factor in the developmentof large brains.

fem 4100 brain & human behavior topic 1: introduction

Documents

brain statement

brain tissue

brain tumors

sheeps brain

brain human behaviortopic

average human brain

false statement

small areas