Overview of the Day

Neuroscience - Part 2 The BrainThe Brain and BehaviorGenetics and Behavior

Why Has the Brain Been so Difficult to Study?

Most of it is enclosed in the skullIt just sits there and makes no obvious

movements [electrical/chemical, not mechanical, like the heart or skeleton]

Appears undifferentiated (all of it looks about the same

Ethics of studying human brainsDifferences between human an animal

brain function

How Can We Figure out How the Brain Works ?

Clinical observations of illnesses and damage to brain injuries in war or work damage to back of brain disrupted vision Phinous Gage, damage to frontal cortex resulted in DPC

Manipulating the brain

create brain injuries destroy parts of brain (lesions) and see what happens [ethical on

humans?--when done for other reasons: e.g., split brain, corpus callosum to ameliorate epilepsy]

stimulate it chemically or eclectically (Delgato and bulls)

Observe it

What about the Brain Would You Observe?

What it looks like (3D, X-ray) brain structure, shapes of different

types of peopleBrain activity

what parts of the brain are firing when people are engaged in different tasks

Brain Imaging Techniques:Technologies for Observing the Brain

CT (computed tomograph) scan X-rays of brain in 3d

PET (positron emission tomograph) scan Depicts activity of different brain areas by showing each

area's consumption of its chemical fuel (glucose). Active areas consume most fuel

MRI (magnetic resonance imaging) scan Detects signals from atoms in brain to give detailed

picture of brain's soft tissue

Major Parts of the Brain

Brainstem (oldest, evolved first)ThalamusCerebellumLimbic systemCerebral Cortex (evolved last)

Brainstem

Since it evolved first, what functions do you think it controls?

Medulla Heartbeat and breathing

Reticular formation arousal and sleeprelays information to other areas of the brain

Thalamus

Switchboard receives information from sensory

neurons and routes it to the higher brain regions that deal with seeing, hearing, tasting, and touching.

Cerebellum

Coordinates voluntary movement

Limbic System

Primarily deals with emotion Amygdala (aggression, fear)

Would psycho-surgery for violent criminals (modifying amygdala) be a good idea?

• Varied results: brain parts not completely isolated in terms of function• Easy to err when trying to localize brain functions

Hypothalamus (hunger, thirst, body temperature, and sexual behavior, pleasure center)

Hippocampus (memory)

Cerebral Cortex

Layer of cells on the top of the brain structure: body's control and information-processing center. that part of the brain most associated with our humanity (thought, planning, language, symbols)

Motor cortex (fine voluntary movements)Sensory cortex (this is where incoming

messages reach the cortex)Association areas (integrate

information) the more intelligent the animal, the greater

the amount of uncommitted association areas electrically probing these areas does not

trigger any specific response

Association areas

Frontal lobe judging, planning, personality, social

skills (Phinehas Gage-DPC)

Auditory and visual cortexes

Divided Brain

Right Half of the brain controls which side of the body? Pictures, faces, visual-spatial What percentage of gifted artists are-left

handedLeft Brain

language, numbers, analysisCorpus callosum (connects right and left

hemispheres of the brain)

Genetics and Behavior

Basic Units Genes: biochemical units of heredity

Chromosomes: egg and sperm cells each have 23 chromosomes: when they combine, the 46 chromosomes contain master plan for an individual's development

Genes and Human Development

Genes influence (G x E) Physical development: height, hair color,

skin color, ear lobe, curl tongue, bend thumb back

Behavioral tendencies: personality (anxiety, sensation seeking, shyness, physical and mental abilities

Individual differences (behavior genetics)Universal human characteristics

(evolutionary psychology)

Behavior Genetics

Hereditary influences on individual differences How we differ from one another (personality

and ability)

To what extent are we a product of our genes vs. our environment? Estimate heritability: the extent to which

differences among individuals is due to genes

Adoption studiesIdentical and fraternal twins, siblings

(natural and adopted) reared together and reared apart (separated

at birth)

Identical twins reared apart are more similar than natural or adopted siblings reared together in: intelligence and personality

Evolutionary Psychology

Why we are all the same: universal human tendencies just as our bodies were designed by natural

selection, so to natural selection designed they way people tend to think and behave--particularly with respect to behaviors and thinking that affects reproduction and survival

universal behavioral tendencies passed on through adaptive genes we all share

Study commonalties among people raised in different cultures preference for sweets, fats, salt fear of snakes and spiders women's preference for men who have status and wealth;

men’s preference for young, attractive females men in groups (coordinated action to achieve a goal,

dominance hierarchies); women in groups (independent, less competitive, more egalitarian)

strong bond between biological parents and their children (children with stepparents 40 more likely to be abused than children who are raised by both biological parents)

Summary

Studying the brainParts of the brainParts of the brain and behaviorDivided brainGenetics and behavior

behavior genetics evolutionary psychology