BIOPSYCHOLOGYEverything that is psychological is

simultaneously biological.

Nervous system, endocrine system, genetics and prenatal environment

DIVISIONS OF THE NERVOUS SYSTEM

• Central nervous system • Peripheral nervous system

DIVISIONS OF THE NERVOUS SYSTEM

• Somatic nervous system • Autonomic nervous system

DIVISIONS OF THE NERVOUS SYSTEM

• Sympathetic nervous system

• Parasympathetic nervous system

• Think: “para-”chute as it slows

you down.

Nervous System

• Steps of the neural chain

Part Definition Function

A. dendrites Bushy fibers of one end of the neuron that receive information

Are stimulated into activity by neurotransmitters

B. axon Pass the information through the cell from the dendrites

The path of the electrical impulse (action potential) thru neuron

C. myelin sheath

Layer of fatty tissue that insulates the axon of some neurons

Speeds the electrical impulse down the axon; degenerated by multiple sclerosis

D. axon terminal

The end of the neuron Upon stimulation it released neurotransmitters into the synapse or takes them back up (reuptake)

E. synapse The tiny gap between dendrites and axon terminals

The space btw where the neurotransmitters move from axon terminal to dendrites

F. vesicles Tiny, near spherical packets within the axon terminal that contain high concentrations of neurotransmitters

Stores the NT until the action potential triggers its release into the synapse

Neurons: the cells that make up the nerves

Types of Neurons

• Sensory (afferent) vs. Motor (efferent) neurons:

• Sensory/afferent neurons take messages away from sensory organs to the brain.

• Motor/efferent neurons take messages from the brain to the muscles resulting in motor tasks.

• Interneurons: central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs. We have billions and billions of these.

Neural communication in the cell

• Neurons are either excited or inhibited and it is “all or nothing”…most votes wins!

Neural communication in the cell

• When “excited” an electrical impulse called an action potential travels down the axon and it is propagated by the opening and closing of sodium and potassium “gates.”

Neural communication between cells

• A synapse (gap) exists between an axon and a neighboring dendrite. When stimulated the axon terminal will release neurotransmitters into the synapse wear they will travel to excite the next neuron.

NeurotransmittersNeurotransmitter Effect

Norepinephrine Helps control alertness and arousal; compliments adrenalinEpinephrine NT that functions to speed up body processes, is highly arousing,

chemically identical to adrenalin but is released by neurons.

Endorphins “endogenous morphine” natural opiates that are released in response to pain and vigorous exercise; an inhibitory NT resulting in pain reduction and pleasurable feelings

Acetycholine (ach) Plays a role in learning and memory. Messenger between a motor neuron and a skeletal muscle. Allows for the contraction of muscles. 90% depletion of ACH in ppl with Alzheimer’s disease.

Dopamine An inhibitory NT. It is strongly associated with our reward system. If it feels good, it probably involves dopamine. Excessive activity at dopamine receptors has been linked to schizophrenia; reduced is associated with Parkinson’s disease.

Serotonin Affects mood, hunger, sleep, and arousal. Prozac and similar anti depressants raise serotonin activity and reduces feelings of anxiety.

GABA NT that functions almost always as an neural inhibitor; it helps you to relax. Alcohol and enhance GABA and bring on sleep.

Chemically Manipulating NT’s

• AGONIST: A molecule that mimics the effects of a NT or blocks the reuptake of a NT so the effects are prolonged. Agonists excited neurons.

• Ex: The venom of a black widow spider acts as an ACH agonist, leading to painful muscle contractions, convulsions, and possible death

• ANTAGONIST: A molecule that inhibits a NT release.

• EX: Botulin, a poison that can form in improperly canned foods, causes paralysis by blocking ACH release from a sending neuron. (Botox works the same way, reducing wrinkles.)

Research has shown that your mood is influenced in part by the amount of serotonin receptor binding. When you are happy, it is likely that you have more serotonin receptors activated. Positive events in your life (like falling in love, perhaps) cause greater serotonin release, increasing receptor binding.

After a little while the serotonin molecule will detach ("unbind") from the recepter and float back into the synapse. When this happens, the receptor stops sending chemical signals to the cell body, and it waits for another serotonin molecule to come along.

(Those yellow things on the membrane of the axon terminal are serotonin reuptake transporters.)

About an hour or so after you take Ecstasy(the peak experience)

When you take Ecstasy, the vesicles

release enormous amounts of serotonin

into the synapse.

This significantly increases serotonin receptor binding (more serotonin in the synapse means a greater chance for some of them to bind to the receptors). This increased receptor activity leads to significant changes in the brain's electrical firing and is primarily responsible for the MDMA experience (i.e. empathy, happiness, increased sociableness, enhanced sensation of touch, etc.).

Notice that there is some dopamine in the synapse as well (the

blue things).

MDMA also causes dopamine release (from dopamine cells).

As you can see, dopamine receptors have also been activated.

Long term effects• Research has shown people who have once used

MDMA regularly have measureable degrade in memory function, attention problems, and impaired executive function such as decision making and planning. They also measure within range to be diagnosed with depression.

• Data is statistically significant (likely not due to chance) BUT confounding variables such as alcohol use and use with other drugs as well as the fact that these a self-reports, not necessarily a representative sample make it difficult to draw causal conclusions.

ENDOCRINE SYSTEMGLAND/ORGAN LOCATION FUNCTION

Hypothalamus Brain Controls the master gland, pituitaryPituitary gland Brain Secretes many different hormones which

regulate the other glands

Thyroid Neck Controls metabolism

Adrenal glands Attached to kidneys Release adrenalin which regulates heart rate, respiration, “fight or flight”

Pancreas Near the stomach Regulates level of sugar in the blood

Ovary Lower abdomen of women

Secretes female sex hormones (estrogen/progesterone)

Testes Testicles Secretes the male sex hormone testosterone

ENDOCRINE SYSTEM

Hormones vs. Neurotransmitters• Some hormones, like adrenaline, are chemically like

neurotransmitters. Therefore, hormones & NTs function in very similar ways.

• They differ in processing speed: NTs communicate very rapidly and hormones move much more slowly throughout the body.

• But even though it takes longer for hormones to have their effect, the effect is often more long lasting.

• Brain > pituitary gland > other glands > hormones > brain

The BRAINThe brainstem consists of the medulla, pons, and

reticular formation. Part of the brain

Location Purpose/function

Medulla(aka medulla oblongata)

Top of the spinal cord, located in the skull

Basic life sustaining functions: heart beat, breathing, vomiting , salivation, coughing, & sneezing; damage here is frequently fatal

Pons Anterior to (to the front of) the medulla

Latin for “bridge”, origins of cranial nerves that cross from left to right sides of the brain. Involved with communication between the cerebellum and the cerebral cortex.

Reticular formation

Within the medulla & pons

Network of neurons that filters incoming stimuli to other areas of the brain; controls arousal

THE BRAINThe thalamus sits atop the brainstem and the cerebellum is

located to the rear of the brainstem.Part of the brain

Location Purpose/function

Cerebellum Rear of brainstem, base of brain

“little brain” coordinates voluntary movement, enables one type of nonverbal learning & memory;

Thalamus top of brainstem

Receives information from all sense (except smell) & routes to higher brain regions; also receives info from brain that goes to cerebellum & medulla

THE BRAINThe limbic system lies on the border of the brain’s older evolutionary

parts and the most advanced cerebral hemisphere.

Hypothalamus Below the thalamus

Monitors blood chemistry, controls the pituitary gland (master gland); key to motivated behaviors such as hunger, thirst, sexual drive, fight or flight…

Amygdala Top of brainstem Influences aggression and fear, activated by emotions

Hippocampus Top of brainstem Keeps track of memories

THE BRAINThe cerebral cortex is the outer layer of the brain’s hemispheres.

It is the body’s control and information-processing center.

Lobes Purpose/functionOccipital lobe Rear areas of the cerebral cortex; vision centerParietal lobe Top to rear area of the cerebral cortex; includes the sensory

cortexTemporal lobe Side area of the cerebral cortex (above ears); hearingFrontal lobe Front area of the cerebral cortex; speaking and motor

activities, higher order thinking such as planning, judging, problem solving

OTHER CORTICAL AREAS(Other areas of the cerebral cortex)

• Association area (cortex): any of the various areas of the cerebral cortex that are not involved primarily in sensory or motor function.

• Broca’s area: area of the frontal lobe associated with the control of speech. (Think “boca”=mouth in Spanish)

• Wernicke’s area: area association with the interpretation of sound

• Aphasia: loss or impairment of the ability to understand language or express oneself through language due to injury or illness.

Illustration of brain structures involved in making conversation.

The Anatomy of the Brain

• http://www.gwc.maricopa.edu/class/bio201/brain/brshpx.htm

THE BRAINCorpus callosum Band of neural fibers that connecting the two brain

hemispheres and carrying messages between themLeft hemisphere Controls the right side of the body, primary location for

speech (Broca’s area), also specialized for math ability, calculation, and logic

Right hemisphere Controls the left side of the body, visual & spatial relations, perception is primarily processed here, music & art better understood on this side of the brain, creativity and intuition are also found here.

THE BRAIN

• ** The idea that we are “left” or “right” brained has been over simplified by “pop” psychology articles. We all use both sides of our brains and anyone who has sustained damage to one or both sides of the brain shows remarkable compensation made by the opposing side.

• “wax on, wax off” activity

BRAIN SCANSTest What does it stand for? How does it work? When is it used?EEG Electroencephalogram Reading of electrical

waves traveling across the brain

Stimuli evoke electrical impulses which will be picked up by the EEG

Lesions Removal or damage to selected brain matter

Animal studies, biopsies, removal of damaged tissue

CAT Computed tomography x-ray photographs Identify head trauma, fractures

PET Positron emission tomography

Shows areas of chemical “consumption” (glucose) w/radioactive tracers

Research which parts of the brains are active or inactive by following the tracers

MRI/ fMRI

Magnetic resonance imaging

Magnets align neural atoms which give off signals when returning to normal

See the soft tissue and fluid areas of the brain and the blood flow

BRAIN SCANS

GENETICS & HUMAN BEHAVIOR

Behavioral geneticists study our differences and weigh the relative effects of heredity and environment.

NATURE VS. NURTUREGenetically, all humans are 99.9% identical. It is

the .1% in conjunction with varying environmental factors that makes us all unique.

Human traits are influenced by gene complexes meaning multiple genes play a role in height, intelligence, temperament, etc.

GENETICS & HUMAN BEHAVIOR

• TWIN STUDIESIdentical >>

Fraternal

Genetics & Behavior

• Identical twins share identical genes and very similar developmental environments

• Fraternal twins share 50% of the same genes and very similar developmental environments

• Separated identical twins share identical genes but very different developmental environments.

Genetics & Behavior• Research shows that identical twins are much

more similar behaviorally than non-identical twins.

• Lykken & McGue found that you are 5.5 times more likely to divorce if your identical twin had divorced.

• Loehlin & Nichols found identical twins to be more similar in abilities, personal traits, and interests, regardless of parental treatment.

Genetics & Behavior• Genetically identical twins reared apart in different

families have consistently shown significant similarities in personality, interests, and behaviors. Those reared together are even more similar.

• Genetically identical twins reared apart have more in common than fraternal twins reared apart.

• Though some researchers feel this may be all due to “chance,” (Besides, how many sets of identical twins reared apart actually exist?) adoption studies strengthen the genetic argument in that adopted children are often NOT similar to their adoptive parents.

Nature vs. Nurture

• “Nurture works on what nature endows.”• Example: Some people are physiologically more

prone to eating disorders, but the environment/culture to which they are exposed can/will enhance their chances or developing an eating disorder.

• What implications does knowing one’s genetic make up and “risk” factors have for our future?

Behavioral geneticists vs. Evolutionary psychologists

• Behavioral geneticists are interested in what makes us unique and in how and why we differ from one another.

• Evolutionary psychologists focus on how we are alike as humans, what commonalities we share.– All people in all cultures show favor to sweet and

fatty foods because the consumption of these are beneficial to survival of famine. Unfortunately, today famine is not often a risk factor, yet we still are driven to consume fatty foods >> obesity.

Mean Genes is a book by Drs. Terry Burnham and Jay Phelan that explores the genetic explanations for our behaviors such as spending habits, eating habits, intimacy, and mating.

Environmental Factors• Prenatal environment: prenatal care, placentas, etc.• Enriched environment: “Those with the most toys

win!” Without exposure to written or signed language prior to adolescence one will never master it.

• Parenting: Has its greatest influence when extreme (abusive, neglectful, etc.)

• Peer Influence: The selection of peers makes it powerful. A child is more likely to become a smoker if peers smoke but not if parents smoke.

• Parent decisions (like where to live) will influence peer selection.