Chapter Two

Biology and Psychology

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Evolution & Evolutionary Psychology

• 1871 Book– The Descent of Man

• Natural Selection (core concept): see p. 45.

• Evolutionary Psychology studies the ways in which adaptation and natural selection are connected with mental processes and behavior.

• The Evolution Project (Video Series)

Heredity: The Nature of Nature
See page 47.

• Heredity

– Transmission of traits from one generation to another through genes

• Genetics

– Branch of biology that studies heredity

• Behavioral genetics

– Study of genetic transmission of structures and traits that give rise to behavior

Behavioral Genetics - p. 47
(Behavior & Heredity)

• Genes - (made of DNA) the basic units of heredity

• Chromosomes - humans normally have 46

• Zygote - a fertilized egg

• Monozygotic twins - identical

• Dizygotic twins - fraternal (may be different sex)

• Recall the Nature-Nurture Issue.

Some genetic abnormalities:

• Tay-Sachs Disease

• Alzheimer’s Disease - affects 10% over age 65. Not a normal part of growing old.

• Down’s Syndrome (p. 50) - extra chromosome on the 21st pair causes mental retardation.

• Phenylketonuria (PKU) - 1 in 14,000 kids cannot metabolize phenylalanine.

• Tourette’s Syndrome - tics

Neurons are individual Nerve Cells

Parts of a neuron: axon, dendrite, soma & synapse

The myelin sheath insulates the axon, and is
implicated in Multiple Sclerosis.

Sensory- "afferent"; Motor - "efferent"

The neural impulse is electrochemical.

"All-or-None" Principle

Glial Cells outnumber neurons 10:1.
Neurotransmitters work at the synapse.
How Neurons Communicate: Click Here for a Video!

Neurotransmitters (page 59)

• Acetylcholine - involved in muscle movement & memory formation. Implicated in Alzheimer’s Disease.

• Dopamine - involved in voluntary movement, learning & memory, attention, and emotions. Implicated in Schizophrenia, Parkinson’s Disease, Tourette's Syndrome, addiction, and obesity.

• Serotonin - involved in emotional arousal, mood, eating & sleep. Implicated in depression, aggression and migraine headaches.

• Noradrenaline - involved in arousal, learning & memory (& mood disorders).

• Endorphins - involved in pain control; the body's "endogenous morphine."

• Gamma-Amino Butyric Acid (GABA) - An amino acid transmitter in the brain whose primary function is to inhibit the firing of neurons. Implicated in anxiety (page 527), Huntington's Chorea and Epilepsy.

• Glutamate - An amino acid neurotransmitter that acts to excite neurons. Implicated in learning and memory (See page 298.) and in brain damage due to Stroke.

The Nervous System (See Page 61.)

Methods of Studying the Brain
(See p.65-67.)
“The Mind is what the brain does.”

• Accidents (Consider Phineas Gage.)

• Electrical Stimulation of the Brain (ESB)

• Electroencephalograph (EEG)

• CAT Scan

• PET Scan

• MRI

Know brain parts on page 68; Fig. 2.13.

Hindbrain:

medulla, pons, cerebellum, Reticular activating system

Mid-brain: eye focusing, pupillary dilation, movement.

Forebrain: most recently evolved parts.

Parts of the Forebrain:

thalamus - sensory relay station

hypothalamus - body temperature, motivation & emotion (eating & sex)

limbic system - memory, motivation & emotion (see p. 70)

cerebrum - Latin for "brain." consists of two hemispheres. Covered with "Cortex."

A Split-Brain Experiment

• The cerebral hemispheres are connected by the Corpus Callosum.

• Some people have had their Corpus Callosum surgically severed, with interesting effects.

• This is done to control severe epilepsy.

Summary of Left & Right Cerebral Hemispheres