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Chapter 3:

Neuroscience and Behavior

Parts for study

• Nervous system

• Brain

• Endocrine system

• Behavior – hereditary and evolutionary

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© 2008 The McGraw-Hill Companies, Inc.

Neurons:

The Basic Elements of Behavior

From Neurons to Nervous System:

The Biology Underlying Behavior

• Your nervous system is living

tissue composed of cells.

• Divided into neurons and glia

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Neuron: Basic Structure

• Dendrites

– Receive

message

s from

other

neurons

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Neuron: Basic Structure

• Axon- Carries

messages destined

for other cells

• Myelin Sheath-

Wrapped around

the axon, a

protective coating

• Soma- cell body

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Neuron: Basic Structure

• All-or-none law

– Neurons are either on or off

• Resting state

– Negative electrical charge within a neuron

• Action potential

– An electric nerve impulse that travels through a neuron, changing the cell’s charge from negative to positive

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Neuron: Basic Structure

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Neural impulses

Hodgkin and Huxley study- find out what this impulse was (p.75)

Squid axons, inserted microelectrodes,

What did they find out?

Ions are present outside of neuron, pos and neg travel across cell membrane at diff times,

Cell is resting, stable- negative charge

When stimulated, positive sodium ions sent in and actions potential happens.

Refractory period lasts seconds, when another action potential cannot take place.

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Neuron continued

• Neurotransmitters- chemicals that are secreted from the Terminal buttons

• Terminal buttons are clusters at end of axon

• Neurons vary in size and shape

• Glia- “glue”, support cells, outnumber neurons 10-1, nourish, eliminate waste,

unsung heroes, new research shows they can communicate as well.

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Neuron: Basic Structure

• Excitatory messages

– A chemical secretion that makes it more likely

that a receiving neuron will fire and an action

potential will travel down its axon

• Inhibitory messages

– A chemical secretion that prevents a receiving

neuron from firing

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Neuron: Basic Structure

• Neurotransmitters

– Chemicals that carry

messages across the

synapse to the dendrite (and

sometimes to the cell body) of

a receiver neuron

• Synapse

– A chemical connections that

bridges the gap between two

neurons

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Neuron: Basic Structure

• Acetylcholine (Ach) – Location

• Brain, spinal cord, peripheral nervous system, especially some of the organs of the parasympathetic nervous system

– Effect

• Excitatory in brain and autonomic nervous system; inhibitory elsewhere

– Function

• Muscle movement, cognitive functioning

Acetylcholine (ACh)

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Neuron: Basic Structure

• Glutamate – Location

• Brain and spinal cord

– Effect

• Excitatory

– Function

• Memory

Glutamate

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Neuron: Basic Structure

• Gamma-amino butyric acid

(GABA) – Location

• Brain and spinal cord

– Effect

• Main inhibitory neurotransmitter

– Function

• Eating, aggression, sleeping

Gamma-amino butyric acid

(GABA)

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Neuron: Basic Structure

• Monamines( also noreph. and serotonin) • Dopamine

– Location

• Brain

– Effect

• Inhibitory or excitatory

– Function

• Muscle disorders, mental disorders, Parkinson’s disease

Dopamine

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Neuron: Basic Structure

• Serotonin

– Location

• Brain and spinal cord

– Effect

• Inhibitory

– Function

• Sleeping, eating, mood, pain, depression

Serotonin

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Neuron: Basic Structure

• Endorphins – Location

• Brain, spinal cord

– Effect

• Primarily inhibitory, except in hippocampus

– Function

• Pain suppression, pleasurable feelings, appetites, placebos

Endorphins

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Neurotransmitters

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The Nervous System and the

Endocrine System

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Central and Peripheral

Nervous Systems

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Central Nervous System

• Spinal Cord

• Reflexes

• Sensory (Afferent) Neurons

• Motor (Efferent) Neurons

• Interneurons

Nervous system

• Includes brain

• Org: 110 billion neur. in brain= 100 trillion

synapses

• Divided into CNS and peripheral

• CNS includes brain and spinal cord

• Peripheral is divided into 2 sections:

– Somatic

– autonomic

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Peripheral Nervous System

• Somatic division

– Controls voluntary movement

• Autonomic division

– Controls that parts of the body that keep us alive – the heart, blood vessels, glands, lungs, etc.

Peripheral continued

• Somatic- skeletal muscles and sensory

organs

• Includes cables to and from muscles to

CNS

• Afferent nerves

• Efferent nerves

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Peripheral Nervous System

CNS

• Brain and Spinal cord

Brain- integrator

Spinal cord- big long axon

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Evolutionary Foundations of

The Nervous System • Evolutionary Psychology

– The branch of psychology that seeks to

identify behavior patterns that are a result of

our genetic inheritance from our ancestors

• Behavioral Genetics

– The study of the effects of heredity on

behavior

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The Endocrine System

• Endocrine system

– Sends messages throughout the nervous system

• Hormones

– Affect the functioning or growth of other parts of the body

• Pituitary gland

– The “master gland”

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The Endocrine System

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The Brain

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Spying On the Brain:

Research Methods

• Electroencephalogram (EEG)

• Computerized Axial Tomography (CAT) Scan

• Positron Emission Tomography (PET) Scan

• Functional Magnetic Resonance Imaging (fMRI)

• Transcranial Magnetic Stimulation (TMS)

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Spying On the Brain:

Research Methods

• Advances in brain imaging also have given

rise to neuroforensics, the application of

brain science, behavioral genetics, and

neural imaging to legal questions

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Spying On the Brain:

Research Methods

be sure to know different technology

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The “Old” Brain

• Central core

– Controls basic

functions like eating

and sleeping

• Medulla

• Pons

• Reticular Formation

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The “Old” Brain

• Central core

– Cerebellum

• Controls balance

– Thalamus

• Relay station for information concerning

senses

– Hypothalamus

• Maintains homeostasis and produces vital

basic behavior

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The Limbic System:

Beyond the Central Core • Part of the brain

that controls eating,

aggression, and

reproduction

– Amygdala

– Hippocampus

– Fornix

Peripheral cont’d

• Autonomic

– Heart, blood vessels, glands

– Heart rate, physiological arousal

– Cannon study

– Divided into sympa and para

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The “New” Brain

• Cerebral cortex

– Responsible for the most sophisticated information processing in the brain

– 4 Lobes

• Association (Speech) areas

– Aphasia

– Broca’s area

– Wernicke’s area

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The “New” Brain

• Motor area

– Responsible for

voluntary movements

of particular parts of

the body

• Sensory area

– Somatosensory area

– Auditory area

– Visual area

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Mending the Brain

• Regeneration of neurons

– Stem cell research

• Neuroplasticity

– Changes in the brain that occur

throughout the life span relating to the

addition of new neurons, new

interconnections between neurons, and

the reorganization or information-

processing areas

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The Specialization of the

Hemispheres

• Hemispheres

– Two symmetrical left and right halves of

the brain that control the side of the

body opposite to their location

• Lateralization

– The dominance of one hemisphere of

the brain in specific functions

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The Split Brain: Exploring the

Two Hemispheres • Surgically cutting the corpus callosum

• Split brain patients

– A person who suffers from independent functioning of the two halves of the brain

– Biofeedback • Procedure in which a person learns to control

through conscious thought internal physiological processes such as blood pressure, heart and respiration rate, skin temperature, sweating, and the constriction of muscles

Biology and behavior

Reminder that the endocrine system plays a role: hormones that affect our processing and behaviors, include

• Pituitary- mater gland

• Adrenal- fight or flight( Cannon study)

• Pineal- wake sleep cycles

• Thyroid-metabolism

• Pancreas insulin

• Ovaries and testes estrogen and testosterone

Genetics and heredity:

• Chromosomes- are DNA strands, 23 pairs

• Genes are DNA segments, also operate in pairs, one dominant and one recessive, child has 50 % probability of

inheriting a gene from parent

• Genotype- our blueprint

• Phenotype- our appearance

• Abnormalities include downs Syndrome, Huntington’s disease and Turners Syndrome

• Our traits are influences by more than one gene- Polygenic traits, so hard to predict certain behaviors since it

can come from many different areas. Family and twin studies assist with figuring it out

• Genetic mapping documents genetic sequences , does not reveal how genes govern behavior but hope to

understand in future issues such as schizo, personality traits etc

• Heredity and role of environment is studied- Plomin 2004 jointly influences behavior but to what degree of

vulnerability?

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Evolutionary

Darwin’s ideas had great influence early on( as did others)

• Noted that some of our characteristics are heritable, looked into why a

species survives

• Reproductive fitness

• Natural selection

Modern models:

• Adaptation- inherited characteristics that increased in a population bc it

helped survival

• Behavior as an adaptive trait: learned beh that increase our reproductive

success, seen in animals and humans , ex on p. 109 in text

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