Princeton AP Psych 22nd: Unit 1: Biological Bases of Behavior

physiological psychology

the study of behavior as influenced by biology; draws from biology and medicine to examine psychological phenomena

traits

distinctive characteristics or behavior patterns that are determined by genetics

evolutionary perspective

how the principles of evolution, including survival of the fittest and natural selection, apply to psychology

heritability

the degree of variance among individuals that can be attributed to genetic variations

environmentality

the degree to which a trait’s expression is caused by the environment in which an organism lives

nature versus nurture debate

the relative influences of genetics and environment

Down syndrome

occurs when there are three copies of the 21st chromosome, which generally causes some degree of intellectual disability

Huntington’s chorea

a genetic disorder that results in muscle impairment that does not typically occur until after age 40

• It is caused by degeneration of the structure of the brain known as the basal ganglia, and it is fatal

• Because of the late onset of the disease, it it frequently passed down to the next generation before its symptoms are manifested

nervous system

the organized network of nerve tissue in the body

central nervous system

comprising the brain and the spinal cord

peripheral nervous system

comprising all other nerves in the body

neurons

A type of cell that receives and sends messages from the body to the brain and back to the body

sensory/afferent neurons

nerves sending information to the brain

motor/efferent neurons

nerves conveying information from the brain

reflexes

quick and involuntary responses to environmental stimuli

interneurons

neurons that communicate between sensory and motor neurons, processing information within the central nervous system

somatic nervous system

responsible for voluntary movement of large skeletal muscles

autonomic nervous system

controls the nonskeletal or smooth muscles, such as those of the heart and digestive tract; these muscles are typically not under voluntary control; divided into the sympathetic and parasympathetic nervous systems

sympathetic nervous system

associated with processes that burn energy; e.g. digestion ceases, blood transfers to skeletal muscle, and heart rate increases

parasympathetic nervous system

the complementary system responsible for conserving energy; e.g. sending blood to the stomach for digestion, slowing the heart rate, and conserving energy

soma

a clearly defined, nucleated cell body

dendrites

receive input from other neurons through receptors on their surface; branching out from the soma

axon

a long, tubelike structure that responds to input from the dendrites and soma

myelin sheath

a fatty coating around neurons; serves as insulation for axons and also speeds up the rate at which electrical information travels down them

nodes of Ranvier

the small gaps between the myelin; help speed up neural transmission

terminal buttons

knobs on the branched end of the axon; releases neurotransmitters across the synapse

synapse

the gap between terminal buttons and cell bodies

neurotransmitters

chemical messengers, which bind with receptors on subsequent dendrites

glial cells

non-neuronal cells that provide support, both physical and chemical, to the neurons

resting membrane potential

an electric potential across the plasma membrane of approximately -70 millivolts (mV)

action potential/nerve impulse

a disturbance in this membrane potential

• caused by movement of ions into and out of the neuron through ion channels, leading to the eventual release of the neurotransmitter

• they are either generated or not, with nothing in between

excitatory neurotransmitters

serve to excite the cell or cause the neuron to fire

inhibitory neurotransmitters

inhibit (or stop) cell firing

enzymes

breaks down neurotransmitters once released

reuptake

absorbs neurotransmitters back into the cell that released it

acetylcholine

affects memory function, as well as muscle contraction, particularly in the heart

serotonin

related to arousal, sleep, pain sensitivity, and mood and hunger regulation

dopamine

associated with movement, attention, and reward; imbalances may play a role in Parkinson’s disease and in schizophrenia

GABA/gamma-Aminobutyric acid

an inhibitory neurotransmitter

glutamate

an excitatory neurotransmitter and the all-purpose counterpart to GABA

norepinephrine

affects levels of alertness; a lack of norepinephrine is implicated in depression

endorphins

the body’s natural painkillers

substance P

appears to be linked to pain, mood, vasodilation, and learning

endocrine system

this system works through groups of cells known as glands, which release substances called hormones

hormones

affect cell growth and proliferation

pituitary gland/master gland

the primary gland releases hormones that, in turn, control hormonal release by many other glands

adrenocorticotropic hormone (ACTH)

stimulates the adrenal glands, resulting in fight-or-flight reactions

adrenal glands

secrete epinephrine and norepinephrine

epinephrine

a hormone and neurotransmitter known as adrenaline

leptin

a hormone involved in regulating hunger and energy, and resistance to leptin is implicated in obesity

ghrelin

tells your brain it is hungry

melatonin

involved with sleep and is controlled by the level of light; production increases when it is dark and is inhibited when it is light

oxytocin

involved with sexual arousal, romantic attachment, and parental bonding; it is also important in the process of childbirth

agonist

they increase the effect of the neurotransmitter at the synapse

antagonists

they decrease the effect of the neurotransmitter at the synapse

alcohol

• depressant

• Decreases dopamine levels

• Dizziness, slurred speech, impaired judgment

• High doses can result in respiratory depression and death

barbiturates

• e.g. Seconal, Nembutal

• depressant

• Inhibit neural arousal centers

• Decrease anxiety; increase judgment

• High doses can result in respiratory depression and death

• Can be very addictive and dangerous when mixed with other depressants or alcohol

tranquilizers

• e.g. Xanax, Valium, Librium

• depressant

• Inhibit neural arousal centers

• Reduce anxiety without inducing sleep

caffeine

• stimulant

• Accelerates heart rate; constricts blood vessels

• Reduces levels of adenosine, a neurochemical regulator of norepinephrine release

• Can lead to irritability, anxiety, insomnia

amphetamines

• e.g. diet, pills, Adderall

• Increase body temperature and heart rate

• Increase production of dopamine and norepinephrine

• Can be addictive

• Produce feelings of euphoria

• High doses can lead to motor dysfunction

cocaine

• stimulant

• Stimulates heart rate and blood pressure

• Increases dopamine, serotonin, and norepinephrine release

• Users feel as though they have increased mental abilities and social ability

• Can be highly addictive

nicotine

• stimulant

• Stimulates acetylcholine transmission

• Increases heart rate

• Has depressant behavioral effects such as decreasing appetite while increasing heart rate and respiration

• Can sometimes cause euphoria and dizziness

• Highly addictive

opioids

• e.g. Oxycodone, Heroin

• depressant

• Activate receptors for endogenous endorphins

• Induce relaxation and euphoria; can relieve pain

• May cause impaired cognitive ability, sweating, nausea, and respiratory depression

• Highly addictive and available only by prescription or though illicit means

hallucinogens

• e.g. LSD and marijuana

• Distort sensory perceptions

• May increase serotonin levels

• May induce sensory synesthesia, in which stimuli from one sense, such as hearing, produce sensory effects in other modalities, such as vision

• Occasionally, the perceptual alterations are extremely unpleasant and terrifying. This state may also be accompanied by paranoia

dependence

when an individual continues using a drug despite overarching negative consequences in order to avoid unpleasant physical and/or psychological feelings associated with not taking it

tolerance

when increasingly larger doses are needed in order for the same effect to occur

withdrawal

the process of weaning off a drug one has become dependent upon; this often involves physical and psychological symptoms of a highly unpleasant nature

hindbrain

• The oldest part of the brain to develop, in evolutionary terms

• Composed of the cerebellum, medulla oblongata, reticular activating system (RAS), and pons

cerebellum

controls muscle tone and balance, coordination of movement, and some procedural learning

brain stem

(which includes the Medulla oblongata) controls involuntary actions, such as breathing, digestion, heart rate, and swallowing (basic life functions)

medulla oblongata

the connection between the brainstem and the spinal cord, carrying multiple important functional centers

reticular activating system (RAS) & the brain’s reward system

controls arousal (wakefulness and alertness). This is also known as the reticular formation. Also controls some voluntary movement and eye movement. Additionally, it plays a role in learning, emotion, and cognition

pons

Latin for “bridge,” a way station, passing neural information from one brain region to another. Also implicated in REM sleep

forebrain

contains the limbic system

limbic system

• Emotional center of the brain

• Composed of the thalamus, hippocampus, amygdala, and hypothalamus

thalamus

relays sensory information; receives and directs sensory information from visual and auditory systems

hippocampus

involved in processing and integrating memories

anterograde amnesia

prevents the formation of new memories

amygdala

implicated in the expression of anger, frustration, and fear

hypothalamus

controls the temperature and water balance of the body; controls hunger and sex drives; orchestrates the activation of the sympathetic nervous system and the endocrine system; and it can be divided into the lateral hypothalamus and ventromedial hypothalamus, the combination of which regulates eating behaviors and body weight

lateral hypothalamus

• The “on switch” for eating

• A lesion would lead to a decreased hunger drive and even self-starvation

ventromedial hypothalamus

• The “off switch”

• A lesion would cause obesity and even death from overeating

cerebral cortex

• The wrinkled outer layer of the brain

• Involved in higher cognitive functions such as thinking, planning, language use, and fine motor control

• Covers two symmetrical-looking sides of the brain known as the left and right cerebral hemispheres

• Can be divided into four distinct lobes: frontal, parietal, temporal, and occipital

sensory cortex

receives sensory input

motor cortex

sends out motor information

left and right cerebral hemispheres

two symmetrical-looking sides of the brain, joined together by the corpus callosum

corpus callosum

a band of connective nerve fibers, joining the two hemispheres together

expressive aphasia

loss of the ability to speak

Broca’s area

a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production

receptive aphasia

the inability to comprehend speech

Wernicke’s area

an area in the left temporal lobe with functions linked to speech comprehension

split-brain patients

people who had their corpora callosa severed to control their epileptic seizures

• Can describe objects without deficit if presented in the right visual field (processed on the left, more verbal side of the brain), but they have great difficulty drawing the image

• If the image is presented in the left visual field (and processed in the more visual right side of the brain), the person can draw or choose the object but cannot explain it verbally

contralateral processing

the ability of (non-split) brains to use both hemispheres and integrate information between them via the corpus callosum

frontal lobe

• Responsible for higher-level thought and reasoning

• That includes accessing working memory, paying attention, solving problems, making plans, forming judgments, and performing movements

• The frontal lobe is located at the front of the brain

parietal lobe

• Handles somatosensory information and is the home of the primary somatosensory cortex

• Receives information about temperature, pressure, texture, and pain

• Located at the top of the brain, moving towards the back of the brain

temporal lobe

• Handles auditory input and is critical for processing speech and appreciating music

• Located at the side of the brain near the ears

occipital lobe

• Processes visual input

• Located at the back of the brain

optic chiasm

where the optic nerves from each eye meet and cross. It's responsible for transmitting visual information. This intersection helps your brain combine what both of your eyes see. Because of this meeting point, when you open your eyes, you get a single image.

association areas

responsible for associating information in the sensory and motor cortices

apraxia

the inability to organize movement