AP psych final review terms

Neuron

Basic cell of the nervous system that processes and transmits information via electrical and chemical signals.

Dendrite

Bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

Axon

Extension of a neuron that passes messages away from the cell body to other neurons or muscles.

Myelin Sheath

Fatty tissue layer segmentally encasing axons; enables faster transmission of neural impulses.

Action Potential

Neural impulse; brief electrical charge that travels down the axon.

Resting Potential

State during which a neuron is not firing; internal charge more negative than the outside.

Threshold

Minimum intensity needed to trigger an action potential in a neuron.

Refractory Period

Period after an action potential during which a neuron cannot fire again.

Synapse

Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

Neurotransmitter

Chemical messengers that cross synaptic gaps between neurons.

Reuptake

Process by which neurotransmitters are taken back into the synaptic vesicles of the sending neuron.

Acetylcholine (ACh)

Neurotransmitter that enables muscle action, learning, and memory.

Dopamine

Neurotransmitter influencing movement, learning, attention, and emotion; excess linked to schizophrenia, deficit to Parkinson's.

Serotonin

Neurotransmitter that affects mood, hunger, sleep, and arousal.

Endorphins

Natural opiate-like neurotransmitters linked to pain control and pleasure.

GABA

Major inhibitory neurotransmitter that helps offset excitatory messages and regulates sleep-wake cycles.

Glutamate

Major excitatory neurotransmitter involved in memory.

Nervous System

Body's electrochemical communication circuitry, consisting of all nerve cells.

Central Nervous System (CNS)

Brain and spinal cord, the decision-making center of the body.

Peripheral Nervous System (PNS)

Sensory and motor neurons that connect the CNS to the rest of the body.

Somatic Nervous System

Part of PNS that controls skeletal muscles and voluntary movement.

Autonomic Nervous System

Part of PNS that controls glands and internal organ muscles (involuntary).

Sympathetic Division

Division of ANS that arouses and expands energy, preparing body for action ("fight-or-flight").

Parasympathetic Division

Division of ANS that conserves energy, calming the body after stress.

Reflex

Simple, automatic response to a sensory stimulus (e.g., knee-jerk).

Endocrine System

Glands that secrete hormones into the bloodstream to influence behavior and emotions.

Hormone

Chemical messenger produced by endocrine glands and carried in blood to target sites.

Pituitary Gland

Master gland in the endocrine system; regulates other glands and releases growth hormone.

Adrenal Glands

Pair of endocrine glands that sit above the kidneys and secrete epinephrine and norepinephrine during stress.

EEG

Electroencephalogram; records electrical activity of the brain via electrodes on the scalp.

CT Scan

Computed tomography scan; X-ray photographs taken from different angles are combined into a composite image.

PET Scan

Positron emission tomography scan; depicts brain activity by showing where a radioactive form of glucose goes while the brain performs a task.

MRI

Magnetic resonance imaging; uses magnetic fields and radio waves to produce computer-generated images of soft tissue.

fMRI

Functional MRI; reveals blood flow and brain activity by comparing successive MRI scans.

Brainstem

Lowest brain region; responsible for automatic survival functions.

Medulla

Base of the brainstem; controls heartbeat and breathing.

Pons

Just above the medulla; helps coordinate movement and control sleep.

Reticular Formation

Network inside the brainstem that filters incoming stimuli and relays important information to other brain areas.

Thalamus

Sensory switchboard at the top of the brainstem; routes messages to the sensory cortex and replies to the cerebellum and medulla.

Cerebellum

"Little brain" at the rear of the brainstem; processes sensory input, coordinates movement, and enables nonverbal learning and memory.

Limbic System

Neural system (including hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

Hypothalamus

Neural structure below the thalamus; directs eating, drinking, body temperature, and governs the endocrine system via the pituitary.

Amygdala

Two lima bean-sized neural clusters in the limbic system; linked to emotion, particularly fear and aggression.

Hippocampus

Neural center in the limbic system that processes memory.

Cerebral Cortex

Thin surface layer of interconnected neural cells covering the cerebral hemispheres; the ultimate control and information-processing center.

Frontal Lobes

Portion of cerebral cortex lying just behind the forehead; involved in speaking, muscle movements, planning, and judgment.

Parietal Lobes

Portion of cerebral cortex at the top and to the rear; receives sensory input for touch and body position.

Occipital Lobes

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

Temporal Lobes

Portion of cerebral cortex above the ears; includes auditory areas.

Motor Cortex

Area at the rear of the frontal lobes that controls voluntary movements.

Sensory Cortex

Area at the front of the parietal lobes that registers and processes body touch and movement sensations.

Association Areas

Areas of the cerebral cortex involved in higher mental functions such as learning, remembering, thinking, and speaking.

Broca's Area

Area in the left frontal lobe that directs muscle movements involved in speech production.

Wernicke's Area

Area in the left temporal lobe involved in language comprehension.

Sensation

Process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Perception

Process of organizing and interpreting sensory information, enabling recognition of meaningful objects and events.

Bottom-up Processing

Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.

Top-down Processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

Selective Attention

Focusing conscious awareness on a particular stimulus, as in the cocktail party effect.

Cocktail-Party Effect

Ability to attend to only one voice among many; filtering out other stimuli yet still able to detect your name in an unattended voice.

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere.

Change Blindness

Failing to notice changes in the environment; a form of inattentional blindness.

Psychophysics

Study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

Absolute Threshold

Minimum stimulation needed to detect a particular stimulus 50% of the time.

Difference Threshold

Minimum difference between two stimuli required for detection 50% of the time (just noticeable difference, or JND).

Weber's Law

Principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).

Signal Detection Theory

Theory predicting how and when we detect the presence of a faint stimulus amid background noise; assumes there is no single absolute threshold.

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation.

Transduction

Conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses our brain can interpret.

Wavelength

Distance from the peak of one light or sound wave to the peak of the next; determines hue in vision, pitch in hearing.

Intensity

Amount of energy in a light or sound wave, which we perceive as brightness or loudness, determined by amplitude.

Hue

Dimension of color determined by the wavelength of light.

Saturation

Purity or vividness of a color.

Brightness

Perceived intensity of light (amount of energy).

Pupil

Adjustable opening in the center of the eye through which light enters.

Iris

Ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the pupil's size.

Lens

Transparent structure behind the pupil that changes shape to help focus images on the retina.

Retina

Light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of neurons that begin the processing of visual information.

Rods

Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision when cones don't respond.

Cones

Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions; detect fine detail and color.

Fovea

Central focal point in the retina, around which the eye's cones cluster.

Optic Nerve

Nerve that carries neural impulses from the eye to the brain.

Blind Spot

Point at which the optic nerve leaves the eye; no receptor cells are located there.

Feature Detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Parallel Processing

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

Young-Helmholtz Trichromatic Theory

Theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color.

Opponent-Process Theory

Theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

Audition

Sense or act of hearing.

Frequency

Number of complete wavelengths that pass a point in a given time (for example, per second); in sound waves, perceived as pitch.

Amplitude

Height of sound wave; determines loudness.

Pitch

Tone's highness or lowness; depends on frequency.

Ear Canal

Pathway through which sound travels to the eardrum.

Eardrum (Tympanic Membrane)

Tight membrane that vibrates with waves entering the ear.

Ossicles

Three tiny bones (malleus, incus, stapes) in the middle ear that pick up vibrations and transmit them to the cochlea.

Cochlea

Coiled, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.

Basilar Membrane

Membrane in the cochlea that contains hair cells which convert vibration into neural signals.

Hair Cells

Receptor cells for hearing that line the basilar membrane and wave in response to sound vibrations.

Place Theory

Theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.

Frequency Theory

Theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.

Volley Principle

Neural cells can alternate firing so that when one cell rests, another fires, enabling a match of frequency up to about 4,000 Hz.