ap psych - unit 2 biological bases of behavior

(most) definitions from myers' psychology 3e

neuron

nerve cell; basic building block of the nervous system

cell body (soma)

the part of the neuron that contains the nucleus; is the “life support center” of the cell

dendrites

a neuron's often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body

axon

neuron extension that passes messages through branches to other neurons, muscles, or glands

myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

glial cells (glia)

cells in the nervous system that support, nourish, and protect neurons; also plays role in learning, thinking, and memory

action potential

a neural impulse; a brief electrical charge that travels down an axon

threshold

the level of stimulation required to trigger a neural impulse

refractory period

a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing

synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron; also known as synaptic gap/synaptic cleft

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons; when released by the sending neuron, they travel across the synapse and bind to receptor sites on the receiving neuron, influencing whether that neuron will generate a neural impulse.

reuptake

a neurotransmitter’s reabsorption by the sending neuron

endorphins

neurotransmitter linked to pain control and pleasure

agonist

a molecule that increases a neurotransmitter’s action

antagonist

a molecule that inhibits or blocks a neurotransmitter’s action

nervous system

the body's fast electrochemical-communication network, consisting of all the nerve cells of the peripheral and central nervous systems

nerves

bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs

central nervous system (CNS)

the brain and spinal cord

peripheral nervous system (PNS)

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles; also called the skeletal nervous system

autonomic nervous system (ANS)

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart).

Its sympathetic division arouses; its parasympathetic division calms.

sympathetic nervous system

division of autonomic nervous system that arouses the body, mobilizing energy

parasympathetic nervous system

division of autonomic nervous system that calms the body (conserves energy)

sensory (afferent) neurons

neurons that carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord

motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

interneurons

neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs

reflex

a simple, autonomic response to sensory stimulus (ex. knee-jerk response)

endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

adrenal glands

pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress

pituitary gland

endocrine system's most influential gland; under the influence of the hypothalamus, it regulates growth and controls other endocrine glands

lesion

tissue destruction; is a naturally or experimentally caused destruction of brain tissue

EEG (electroencephalogram)

an amplified recording of the waves of electrical activity sweeping across the brain's surface. These waves are measured by electrodes placed on the scalp

MEG (magnetoencephalography)

a brain imaging technique that measures magnetic fields from the brain's natural electrical activity

CT (computed tomography) scan (CAT scan)

a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain's structure

PET (positron emission tomography) scan

a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue; show brain anatomy

fMRI (functional MRI)

a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans; show brain function as well as structure.

brainstem

the oldest part and central core of the brain; is responsible for automatic survival functions (heartbeat and breathing); involved in focus of attention patterns of arousal

medulla

the base of the brainstem; controls vital autonomic functions such as heartbeat, blood pressure, and breathing

reticular formation

a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal

cerebellum

the "little brain" at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance (motor movements), and enabling nonverbal learning and (muscle) memory

limbic system

neural system (including the amygdala, hypothalamus, and hippocampus) located below the cerebral hemispheres; associated with emotions and drives (fighting, feeding, fleeing, & reproductive behavior); regulates emotions

thalamus

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

hypothalamus

connects with other regions of the brain; responsible for control of hunger, thirst, emotions, body temperature regulation, and circadian rhythms

amygdala

an almond-shaped structure; involved in the experience of negative emotions (ex. fear and anger)

hippocampus

part of the limbic system that processes conscious, explicit memories; decreases in size and function as we age

cerebral cortex

outer layer of the brain that was the last part to evolve; responsible for executive functioning, thinking; is divided up into parts (lobes)

frontal lobe

portion of cerebral cortex located behind the forehead; associated with higher level cognition, reasoning, expressive language/speaking, and motor skills

parietal lobe

middle section of cerebral cortex; associated with sensory (tactile) information (ex. pressure, touch, and pain)

occipital lobe

the portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields

temporal lobe

the portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

an area at the front of the parietal lobes that registers and processes body touch and movement sensations

broca’s area

left frontal hemisphere

broca’s aphasia

a condition where you know what you want to say and can understand others’ words but cannot make the words

wernicke’s area

usually located in the left temporal lobe

wernicke’s aphasia

a condition where you may be saying words that do not make sense; can’t understand others and do not know what you are trying to communicate

aphasia

loss of ability to understand or express speech caused by brain damage

association areas

areas of the cerebral cortex that are not involved in primary motor or sensory functions; involved in higher mental functions such as learning, remembering, thinking, and speaking

plasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience

neurogenesis

the formation of new neurons

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

split brain

a condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

consciousness

subjective awareness of ourselves and our environment

cognitive neuroscience

the interdisciplinary study of the brain activity linked with cognition; includes perception, thinking, memory, and language

dual processing

the principle that information is often simultaneously processed on separate conscious and unconscious tracks

blindsight

a condition in which a person can respond to a visual stimulus without consciously experiencing it

parallel processing

processing many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions

sequential processing

processing one aspect of a problem at a time; generally used to process new information or to solve difficult problems

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior

heredity

the genetic transfer of characteristics to offspring from parents

environment

every nongenetic influence, from prenatal nutrition to the people and things around us

chromosomes

threadlike structures made of DNA molecules that contain the genes

DNA (deoxyribonucleic acid)

a complex molecule containing the genetic information that makes up the chromosomes

genes

the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

identical (monozygotic) twins

develop from a single fertilized egg that splits in two, creating two genetically identical organisms

fraternal (dizygotic) twins

develop from separate fertilized eggs; are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment

heritability

the proportion of variation among individuals in a group that we can attribute to genes; may vary depending on the range of populations and environments studied

interaction

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity)

molecular genetics

the subfield of biology that studies the molecular structure and function of genes

molecular behavior genetics

the study of how the structure and function of genes interact with our environment to influence behavior

epigenetics

prefix meaning "above" or "in addition to”; the study of environmental influences on gene expression that occur without a DNA change

evolutionary psychology

the study of the evolution of behavior and the mind, using principles of natural selection

natural selection

the principle that inherited traits that better enable an organism to survive and reproduce in a particular environment will (in competition with other trait variations) most likely be passed on to succeeding generations.

mutation

a random error in gene replication that leads to a change

social scripts

a culturally modeled guide for how to act in various situations

consciousness

subjective awareness of ourselves and environment

sleep

periodic, natural loss of consciousness

circadian rhythm

bodies’ biological clock; regular body rhythms that occur on a 24 hour cycle

REM (rapid eye movement) sleep

recurring sleep stage when vivid dreams commonly occur; “paradoxical sleep”, when muscles are relaxed but other body systems are active

NREM-1

brief, near-waking sleep with irregular brain waves (theta waves); will only experience this stage once a night, may experience hallucinations or hypnagogic moments

NREM-2

stage in which we are in very light sleep and can easily be woken up; sleep spindles and theta waves occur

NREM-3

deep sleep where we are hard to wake up when in this stage; experience slow delta waves (sleepwalking or night terrors in this stage)

hallucinations

false sensory experiences that occur without a sensory stimulus

hypnagogic sensations

bizarre experiences while transitioning to sleep (ex. falling or floating sensation)

suprachiasmatic nucleus (SCN)

pair of cell clusters in hypothalamus; controls circadian rhythms + responds to light