AP PSYCHOLOGY UNIT 3: BIOLOGICAL BASES OF BEHAVIOR

dendrites

input fibers that carry electrical signals into a neuron from connected cells.

soma (cell body)

control center of neuron, integrates inputs from all dendrites, determines whether neuron should fire or not

axon

output fiber carries electrical signal from a neuron to a neighboring cell, neurons have one each, larger than dendrites, divide into branches at end called terminals

myelin sheath

a layer of fatty tissue that covers around the axon, enables greater transmission speed of neural impulses as impulses jump from node to node, composed of glial cells (glove), support, nourish, protect neurons.

synapse

the junction between the axon tip and the dendrite of the receiving neuron, called the synaptic gap or cleft as well

resting state

a neuron has a slightly negative charge, negative ions mostly inside cell, positive ones outside.

level of excitation

level of stimulation needed for electrochemical communication to occur.

action potential

brief charge that travels down the axon as it becomes depolarized, travels down to terminal where it causes neuro transmitters that bind to specific receptor sites on receiving neurons to fire.

refractory phase

return to state of resting slightly negative charge (polarization), no amount of stimulation can cause the neurons to fire again in this stage, absolute refractory phase is followed by relative refractory phase in which neuron needs more stimulation to fire again.

excitatory neurotransmitter

excite the cell into firing

inhibitory neurotransmitter

inhibit the nerve cell from firing

serotonin

regulates mood, eating, sleeping, and arousal, prozac and ecstasy work by boosting its effects

dopamine

a neurotransmitter, or chemical messenger, that plays a crucial role in various brain functions, including reward, motivation, movement, and learning. It's often called the "pleasure molecule" because it's released when we experience pleasure or things we find enjoyable, reinforcing those behaviors., particularly in basal ganglia, lack= Parkinson's or catatonic, overabundance, associated with Tourrete's and schizophrenia

acetylcholine

regulates cognitive functioning and memory, Alzheimer's associated with loss of it in neurons that connect with hippocampus, nicotine is an agonist (mimics it), thats why cigarettes boost arousal and concentration

norepinephrine (noradrenalin)

regulates alertness and wakefulness, too much=mania, too little=depression, puts the body on "red alert" during stressful or exciting situations, coke and amphetamines boost levels

gaba

(agamma amniobutyric acid), inhibits the action of target cells, low levels: implicated in anxiety and epilepsy, alcohol and barbiturates raise levels

endorphins

"morphine within", natural opiate-like neurotransmitter linked to pain control and pleasure, exercise linked to raising endorphin level

glutamate

most abundant excitatory n.t., plays significant role in learning and memory

afferent neurons (sensory neurons)

takes info from senses to brain

interneuron

once info reaches brain, it takes message and sends it along

efferent neurons (motor neurons)

takes instructions back to muscles

Central Nervous System (CNS)

made up of two major components: brain and spine, receives, processes, interprets, and stores incoming sensory info, sends out messages for muscles, glands, and internal organs.

Peripheral Nervous System (PNS)

consists of nerves/tissue outside brain and spinal cord, two categories: somatic and autonomic nervous systems.

somatic

(skeletal), consists of nerves that are connected to sensory receptors and to skeletal muscles that permit voluntary action, muscles, joints, skin, associated with all body movement

autonomic

controls autonomic functions of the body, controls fight or flight response

Autonomic: sympathetic

mobilizes body to respond to stress, accelerates some functions (heart, b.p.) but conserves resources (digestion slows)

Autonomic: parasympathetic

responsible for slowing down body after stress response

Wilder Penfield

stimulated brain with electrical probes while patients underwent surgery for epilepsy, created maps of sensory and motor cortices

localization

major parts of brain perform different (though sometimes overlapping) tasks

plasticity

in cases of injury certain structures can take on new tasks

hindbrain

consists of structures in the top part of the spinal cord, controls basic biological functions that keep us alive

medulla oblongata

(hindbrain) regulates heart rate, b.p., breathing, etc.

pons

(hindbrain) connects the hindbrain with the mid and fore brains, involved in control of facial expressions

cerebellum

(hindbrain) "little brain", coordinates voluntary movement and balance, damaged in people with autism

midbrain

located just above the spinal cord, and hindbrain, below forebrain, small in humans, coordinates simple movements with sensory info, contains reticual formation: nerve network in brain stem, plays role in controlling arousal, if damaged, coma results

basal ganglia

(midbrain), body movements and speech, overactive: Tourrette's, under-active= Parkinson's

nucleus acumbens

(midbrain), plays central role in rewards, laughter, sexuality, etc, high concentration of serotonin and dopamine pathways

thalamus

(forebrain) located on top of brain stem, responsible for receiving sensory signals and sending them to appropriate ares in the forebrain, all senses except smell

hypothalamus

(forebrain) small structure below thalamus, controls metabolic functions: body temp., hunger, thirst, endocrine system, libido

amygdala

(forebrain) almond shaped near the front of brain, involved in the arousal and regulation of emotion and initial reaction to sensory info

hippocampus

(forebrain) involved in storage of new info, memories

limbic system

made up of thalamus, hypothalamus, amygdala, and hippocampus, deals with emotions and memory

cerebral cortex/cerebrum

grey, wrinkled surface that is densely packed with neurons, located in upper forebrain, connections between neurons grow as we learn and develop, surface is wrinkled to increase surface area (convolutions)

left hemisphere

logic and reasoning (detail oriented) number manipulation, arithmetic, language (grammar skills) right handed touch, movement.

right hemisphere

spatial construction, non-verbal imagery, face recognition, more "big picture" oriented (initiative)

frontal lobe

large area, 1/2 of brain, goal oriented behavior, future planning, believed responsible for abstract thought and emotional control, contains Broca's area: controls muscles involved in speech, thin, vertical strip at back of cortex, motor cortex: sends signals to our muscles; involuntary movement

parietal lobe

located behind frontal lobe, contains somato-sensory cortex: thin, vertical strip, receives incoming touch sensations, both the motor and somato-sensory cortices are organized similarly: top receives sensations from bottom of body; and vice-versa, involved in math/spatial skill

occipital lobe

located at the very back of brain, farthest from eyes, however, one major function is to interpret messages from eyes into visual cortex, impulses from right half of each retina are processed in the visual cortex of the left side, and vice-versa.

temporal lobe

processes sound sensed by ears, sound waves processed, turned into neural impulses and interpreted in auditory cortex.

endocrine system

system of glands that secrete hormones that affect many different biological functions in body, controlled by hypothalamus

adrenal gland

produces adrenaline

melatonin

regulates biological rhythm, i.e. sleep, controlled by pineal gland, inhibited by light, increased by dark

monozygotic

identical twins (from one egg)

dizygotic

fraternal twins (from two eggs)

Thomas Bouchard

studied 100 identical twins, who were raised separately.