Chapter Two

Module 2.1

The Neuron (Figure 2.1)

Neurons

• Structure of the neuron

– Soma

– Axon, neural impulses

– Terminal buttons

– Neurotransmitters

– Synapse

– Dendrites

Neurons

• Types of neurons

– Sensory neurons (afferent)

– Motor neurons (efferent)

– Interneurons (associative)

Neurons

• Neural impulses

– Positive and negative ions

– Resting potential

– Depolarization

– Action potential, all-or-none principle

– Release of neurotransmitters

– Refractory period

An Action Potential

How Neurons Communicate (Figure 2.3)

Neurotransmitters

• Transmit message across synapse

• Receptor sites on postsynaptic neuron

• Excitatory effect

– Suppressed by

• Reuptake

• Enzymes

• Neuromodulators

• Inhibitory effect

Neurotransmitters

• Normal functioning requires a balance

• Disorders may result from:

– Neurotransmitter excess

– Neurotransmitter deficit

– Irregularities in functioning

• Influenced by drugs

– Antagonists

– Agonists

Neurotransmitters

• Examples

– Acetylcholine

– Dopamine

– Glutamate

– GABA

– Serotonin

– Norepinephrine

– Endorphins

Module 2.2

The Peripheral Nervous System: Your Body’s Link to the
Outside World

• Somatic Nervous System

– Carries information from sense organs to CNS

– Relays motor commands to muscles

Peripheral Nervous System

• Autonomic Nervous System

– Regulates involuntary internal bodily processes

– Operates automatically

– Two branches

• Sympathetic (accelerates bodily processes)

• Parasympathetic (slows bodily processes)

Module 2.3

The Central Nervous System: Your Body’s Master Control Unit

Central Nervous System

• Brain

• Spinal Cord

The Spinal Cord

• Column of nerves extending from brain

• Protected by spine

• Spinal reflex

– Controlled at level of spinal cord

– Bypasses brain

The Brain

• Hindbrain

• Midbrain

• Forebrain

Hindbrain

• Medulla (4)

• Pons (3)

• Cerebellum (5)

Midbrain

• Reticular formation

Forebrain

• Thalamus

• Basal ganglia

• Hypothalamus

• Limbic system

– Amygdala

– Hippocampus

• Cerebral cortex

Forebrain

• Thalamus

• Basal ganglia

• Hypothalamus

• Limbic system

– Amygdala

– Hippocampus

• Cerebral cortex

Cerebral Cortex

• Cerebral hemispheres

• Corpus callosum

• Four lobes

– Occipital

– Parietal

– Frontal

– Temporal

• Association areas

Cerebral Cortex

• Cerebral hemispheres

• Corpus callosum

• Four lobes

– Occipital

– Parietal

– Frontal

– Temporal

• Association areas

Module 2.4

Methods of Studying the Brain

Recording and Imaging Techniques

• EEG (electroencephalograph)

• CT (computed tomography) scan

• PET (positron emission tomography) scan

• MRI (magnetic resonance imaging)

• fMRI (functional MRI)

Experimental Methods

• Lesioning

• Electrical recording

• Electrical stimulation

Module 2.5

The Divided Brain: Specialization of Function

Lateralization

• Division of functions between right and left hemispheres

• Left: verbal, logic, problem solving

• Language: Broca’s area, Wernicke’s area, aphasia

• Right: nonverbal, spatial, music appreciation

Handedness

• Right-handed versus left-handed

• Many factors

– Role of genetics

– Social factors

• Pressure to use right hand for writing

– Prenatal hormones

Split-Brain Research

• Treatment for severe epilepsy

– Surgery to sever the corpus callosum

• Split-brain patients

– Retain intellect and personality

– Researched by Sperry and Gazzaniga

• Differences in perception, language in special testing circumstances

Split-Brain Study (Figure 2.17)

Brain Damage and Psychological Functioning

• Case of Phineas Gage: prefrontal cortex damage

Module 2.6

The Endocrine System: The Body’s Other Communication System

Endocrine System

• Many glands that release hormones

– Pancreas

– Pituitary gland (“master gland”)

– Hypothalamus:

– Pineal gland: melatonin

– Adrenal glands

– Gonads (sex glands: ovaries or testes)

• Functions to maintain homeostasis

Hormones and Behavior

• Testosterone and aggression

• Thyroid hormones and metabolism

– Excess: anxiety and irritability

– Deficit: sluggishness

• Premenstrual syndrome (PMS)

Module 2.7

Genes and Behavior: A Case of Nature and Nurture

Genetic Influences on Behavior

• The nature-nurture problem

– Is behavior determined by…?

• Nature: genetics

• Nurture: environment and culture

Basic Concepts of Genetics

• Genotype versus phenotype

• DNA (deoxyribonucleic acid)

• Genes

• Chromosomes

• Germ cells

• Polygenic traits

Kinship Studies

• Rationale: to distinguish the roles of heredity and environment in behavior

• Types:

– Familial association studies

– Twin studies

• Identical (MZ) vs. fraternal (DZ) twins

• Concordance rates

– Adoptee studies

Module 2.8

Application: Biofeedback Training: Learning by Listening to the Body

Biofeedback Training (BFT)

• What is it?

• Monitoring equipment provides information about internal functioning

– Heart rates

– Blood pressure

– Muscle tension

– Temperature

– Others

• Learn to control body through feedback