copyright © allyn & bacon 2007 chapter 3 biopsychology and the foundations of neuroscience this...

Copyright © Allyn & Bacon 2007

Chapter 3Chapter 3

Biopsychology and the Foundations of Neuroscience

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Some Brain Facts…Some Brain Facts…

It is about the size of grapefruit

3 pounds, pinkish-gray, wrinkled surface

100 billion nerve cells, sometimes with up to 10,000 connections to other cells

At birth the brain has extra nerve cells that die off; by adolescence that stabilizes and the total number is constant later on

There is some loss and gain through adulthood, but by age 70 we end up with over 98%


What is Biopsychology?What is Biopsychology?

Biopsychology –The specialty in psychology that studies the interaction of biology, behavior, and the environment

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


Evolution has fundamentally shaped psychological

processes because it favors genetic variations that

produce adaptive behavior

How Are Genes and How Are Genes and Behavior Linked?Behavior Linked?


How Are Genes and How Are Genes and Behavior Linked?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


Evolution and Natural SelectionEvolution and Natural Selection

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


How Natural Selection WorksHow 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)


Genes and InheritanceGenes and Inheritance

Genotype – An organism’s genetic makeup

Phenotype –An organism’s observable physical characteristics


Genes and InheritanceGenes and Inheritance

Mutations – Genetic variations, which occur randomly, especially during the recombination of chromosomes in sexual reproduction


Chromosomes, Genes, and DNAChromosomes, Genes, and DNA

DNA (deoxyribonucleic acid)– A long, complex molecule that encodes genetic characteristics

Genes (they are like words in a sentence)–The functional units of a chromosomeComposed of nucleotides—they are like the

letters in words (A,G,T,C)


Sex chromosomes –The X and Y chromosomes that determine our physical sex characteristics

Chromosomes, Genes, and DNAChromosomes, Genes, and DNA

Chromosomes (like a string of words; they include punctuation and timing)– Tightly coiled threadlike structures along which the genes are organized


Genetic Explanations for Genetic Explanations for Psychological ProcessesPsychological Processes

Genes influence our psychological characteristics as well as our physical traits—the complete package of human genes=30,000

There are 46 chromosomes; 23 pairs

Multiple genes contribute to schizophrenia, Alzheimer’s disease; an extra chromosome 21 results in Down syndrome


The body’s two communication systems, the

nervous system and the endocrine system, both use

chemical messengers to communicate with targets

throughout the body

How Does the Body How Does the Body Communicate Internally?Communicate Internally?


The NeuronThe Neuron

Types of NeuronsSensory neurons—afferent--(carry

messages from sense receptors towards the CNS)

Motor neurons—efferent--(carry messages from CNS toward muscles and glands)

Interneurons (carry messages between nerve cells)


The Structure of a NeuronThe Structure of a Neuron


The Neural ImpulseThe Neural Impulse

Neural impulse –Brief electric surge that carries the neuron’s message

Ions –Charged particles that are moved across the cell membrane


The Neural ImpulseThe Neural Impulse

Resting potential—negative—when the cell is inactive and ready to fire

Action potential—impulse caused in a fraction of second when the charge changes from negative to positive…this is done in an all or none manner

Synapse—gap between neurons or neurons and muscles/glands

Synaptic transmission—relaying information across the synapse by use of chemical neurotransmitters


NeurotransmittersNeurotransmitters

Neurotransmitters –Chemical messengers that relay neural messages across the synapse


Seven Important NeurotransmittersSeven Important Neurotransmitters

DopamineDopamine

SerotoninSerotonin

AcetylcholineAcetylcholine

GlutamineGlutamine

NorepinephrineNorepinephrine

GABAGABA

EndorphinsEndorphins



DopamineDopamine

Serotonin

Acetylcholine

Glutamine

Norepinephrine

GABA

Endorphins

Normal Function:Normal Function:

Produces sensations of Produces sensations of pleasure and reward; used pleasure and reward; used

by CNS neurons in by CNS neurons in voluntary movementvoluntary movement

Problems with Imbalance:Problems with Imbalance:

Schizophrenia, Parkinson’s Schizophrenia, Parkinson’s diseasedisease

Substances that Affect:Substances that Affect:

Cocaine, amphetamines, Cocaine, amphetamines, Ritalin, alcoholRitalin, alcohol



Dopamine

SerotoninSerotonin

Acetylcholine

Glutamine

Norepinephrine

GABA

Endorphins


Regulates sleep and Regulates sleep and dreaming, mood, pain, dreaming, mood, pain,

aggression, appetite and aggression, appetite and sexual behaviorsexual behavior


Depression, certain anxiety Depression, certain anxiety disorders, obsessive-disorders, obsessive-compulsive disordercompulsive disorder


Prozac, hallucinogenics Prozac, hallucinogenics (e.g. LSD)(e.g. LSD)



Dopamine

Serotonin

Acetylcholine

Glutamine

NorepinephrineNorepinephrine

GABA

Endorphins


Controls heart rate, sleep, Controls heart rate, sleep, sexual responsiveness, sexual responsiveness,

stress, vigilance and stress, vigilance and appetiteappetite


High blood pressure, High blood pressure, depressiondepression


Tricyclic antidepressants, Tricyclic antidepressants, beta blockersbeta blockers



Dopamine

Serotonin

AcetylcholineAcetylcholine

Glutamine

Norepinephrine

GABA

Endorphins


Primary transmitter used by Primary transmitter used by neurons carrying messages neurons carrying messages

from CNS; involved in from CNS; involved in some kinds of learning and some kinds of learning and

memorymemory


Certain muscular disorders, Certain muscular disorders, Alzheimer’s diseaseAlzheimer’s disease


Nicotine, botulism toxin, Nicotine, botulism toxin, curare, atropinecurare, atropine



Dopamine

Serotonin

Acetylcholine

Glutamine

Norepinephrine

GABAGABA

Endorphins


Most prevalent inhibitory Most prevalent inhibitory neurotransmitter in neurons neurotransmitter in neurons

of CNSof CNS


Anxiety, epilepsyAnxiety, epilepsy


Barbiturates, tranquilizers Barbiturates, tranquilizers (e.g. Valium, Librium), (e.g. Valium, Librium),

alcoholalcohol



Dopamine

Serotonin

Acetylcholine

GlutamineGlutamine

Norepinephrine

GABA

Endorphins


Primary excitatory Primary excitatory neurotransmitter in CNS; neurotransmitter in CNS; involved in learning and involved in learning and

memorymemory


Brain damage after strokeBrain damage after stroke


PCP (“angel dust”)PCP (“angel dust”)



Dopamine

Serotonin

Acetylcholine

Glutamine

Norepinephrine

GABA

EndorphinsEndorphins


Pleasurable sensations and Pleasurable sensations and control of paincontrol of pain


Lowered levels resulting Lowered levels resulting from opiate addictionfrom opiate addiction


Opiates: opium, heroin, Opiates: opium, heroin, morphine, methadonemorphine, methadone


PlasticityPlasticity

Plasticity –Ability of the nervous system to adapt or change as the result of experience; sometimes helps the nervous system adapt to physical damage


Glial CellsGlial Cells

Glial cells (from the Greek for “glue”)• Provide structural support for neurons• Help in forming new synapses• Form myelin sheath• MS (multiple sclerosis) attacks the myelin

sheath resulting in poor conduction and loss of movement control


The Organization of the The Organization of the Nervous SystemNervous System

Nervous systemNervous system

Peripheral nervous Peripheral nervous systemsystem

Central nervous Central nervous system (CNS)system (CNS)

AutonomicAutonomicnervous systemnervous system

SomaticSomaticnervous system—nervous system—splits into sensory splits into sensory

and motor NSand motor NS

SympatheticSympatheticnervous systemnervous system

Parasympathetic Parasympathetic nervous systemnervous system


The Endocrine SystemThe Endocrine System(the body’s chemical messenger system)


The Endocrine SystemThe Endocrine System

Pituitary gland – Master gland that produces hormones influencing the secretions of all other endocrine glands; produces hormone that influences growth; attached to hypothalamus


How Does the Brain How Does the Brain Produce Behavior and Produce Behavior and

Mental Processes?Mental Processes?

The brain is composed of many specialized modules that work together to create

mind and behavior


Windows on the BrainWindows on the Brain

EEG (electroencephalograph) – Device for recording brain waves, typically by electrodes placed on the scalp

Brain waves –Patterns of electrical activity generated by the brain



Epilepsy – Brain disorder that is often marked by seizures and loss of consciousness; caused by out-of-control electrical activity in the brain



Lesions –Tissue damage that results from disease or injury



Brain scans – Recordings of the brain’s electrical or biochemical activity at specific sites• CT scanning (computerized tomography) X rays are

passed through at various angles creating a static image of brain structure

• PET scanning (positron emission tomography) senses low-level radioactive glucose to create brightly colored areas of activity

• MRI (magnetic resonance imaging) also functional or fMRI creates highly detailed pictures from pulses of magnetic energy


Three Layers of the BrainThree Layers of the Brain

Brain stem and cerebellumDrive vital functions, such as heart rate,

breathing, digestion

Limbic systemAdds emotions, complex motives, increased

memory abilities

CerebrumEnables reasoning, planning, creating,

problem solving


The Brain Stem and CerebellumThe Brain Stem and Cerebellum

Thalamus

Pons

Cerebellum

Medulla

Brain stem


The Limbic SystemThe Limbic System

Hypothalamus –Serves as the brain’s blood-testing laboratory, constantly monitors blood to determine the condition of the body



Amygdala –Involved in memory and emotion, particularly fear and aggression



Hippocampus –Involved in establishing long-term memories


The CerebrumThe Cerebrum

Cerebrum –Topmost layer of the brain; the bulbous cap over the limbic system

Cerebral cortex –Thin gray-matter covering of the cerebrum; carries on thinking and perceiving=2/3 of brain’s total mass

Cerebral hemispheres –The two walnut shaped halves of the cerebrum, connected by the corpus callosum


The Four Lobes of the The Four Lobes of the Cerebral CortexCerebral Cortex

Frontal lobes(movement…motor cortex, planning, deciding, perceiving)

Parietal lobes(touch sensation…somatosensory cortex and spatial relationships)

Occipital lobes(contain visual cortex)

Temporal lobes(process sounds/speech and has some ties to memory)


The Cooperative BrainThe Cooperative Brain

Association cortex –Cortical regions that combine information from various other parts of the brain


Cerebral DominanceCerebral Dominance

Cerebral dominance –Tendency of each brain hemisphere to exert control over different functions

Aphasia –The loss of speech caused by brain damageSpeech production lies in the frontal lobe, left hemisphere (Broca’s area. Understanding language lies in the left parietal and temporal lobes (Wernicke’s area).

Spatial orientation –Process of locating one’s body or other objects in space


Specialization of the Specialization of the Cerebral HemispheresCerebral Hemispheres

Left Hemisphere Right Hemisphere• Spontaneous

speaking and writing

• Responses to complex commands

• Word recognition• Memory for words

and numbers• Sequences of

movements

• Positive emotion

• Repetitive but not spontaneous speaking

• Responses to simple commands

• Facial recognition• Memory for shapes

and music• Spatial interpretation• Emotional

responsiveness• Negative emotion


The Split BrainThe Split Brain

Split-brain patients – Individuals who have had the corpus callosum surgically severed

Duality of consciousness – Condition in which a split-brain patient has a separate consciousness in each hemisphere


End of Chapter 3End of Chapter 3

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