AP PSYCH UNIT 1

Sensation

the process by which our sensory receptors and nervous system receive, and represent stimulus energies from our environment

transduction

conversion of one form of energy to another; the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret

Absolute threshold

the minimum stimulus energy needed to detect a particular stimulus 50% of the time

Sensory adaptation

diminished sensitivity as a consequence of constant stimulation

Sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste

Just-noticeable difference

the smallest difference between 2 stimuli that can be consistently and accurately detected on 50% of trials

Weber's Law

the principle that, to be perceived as different, 2 stimuli must differ by a constant minimum percentage (rather than a constant amount)

Accommodation

the process by which the eye's lens changes shape to focus near or far objects on the retina

Lens

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

Retina

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

Rods

retinal receptors that detect black, white, and gray, and are sensitive to movement; necessary for peripheral and twilight vision, when cones don't respond

Cones

retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions; detect fine detail and give rise to color sensations

Blind Spot

the point at which the optic nerve leaves the eye, creating a vision deficiency because no receptor cells are located there

Fovea

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

Trichromatic (three color) theory

one of several concepts of the physiological basis of color vision, as derived from experiments on color mixture in which all hues were able to be matched by a mixture of 3 primary colors (red, green, or blue) (also Young-Helmholtz theory)

Opponent-process theory

the theory that opposing retinal processes (red-green, blue-yellow, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green

Pitch

a tone's experienced highness or lowness; depends on frequency

Amplitude

height of a wave, determines its loudness for sound

Sensorineural hearing loss

hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; the most common form of hearing loss, also called nerve deafness

place theory

in hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated

frequency theory

in hearing, the 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 theory

the principle that individual fibers in an auditory nerve respond to one or another stimulus in a rapid succession of rhythmic sound stimuli, allowing the nerve to reflect a more rapid frequency of stimulation

conduction deafness

a less common form of hearing loss, caused by damage to the mechanical system that conducts sound waves to the cochlea

gate-control theory

the theory that the spinal cord contains a neurological 'gate' that blocks pain signals or allows them to pass on to the brain

olfaction

the sense of smell

pheromones

a chemical signal that is released outside the body by members of a species and influences the behavior of other members of the same species

gustation

the sense of taste

Kinesthesia

our movement sense - our system for sensing the position and movement of individual body parts

Vestibular sense

our sense of body movement and position that enables our sense of balance

Semicircular canals

a set of 3 looped tubular channels in the inner ear that detect movements of the head and provide the sense of dynamic equilibrium that is essential for maintaining balance

Synesthesia

a condition in which stimulation of one sense generates a simultaneous sensation in another

prosopagnosia

a form of visual agnosia in which the ability to perceive and recognize faces is impaired

phantom limb syndrome

the feeling that an amputated limb is still present, often manifested as tingling or occasionally painful sensation in the area of the missing limb

Supertasters

a person with uncommonly low gustatory thresholds and strong responses to moderate concentration of taste stimuli; have high numbers of taste buds

medium tasters

average taste perception

nontasters

fewer taste buds and reduced sensitivity

neuron

a nerve cell; the basic building block of the nervous system.

glial cells

cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory.

Action potential

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

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 response 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; the tiny gap at this junction

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, thereby influencing whether that neuron will generate a neural impulse.

reuptake

a neurotransmitter's reabsorption by the sending neuron.

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 speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

Peripheral nervous system (PNS)

the sensory and motor neurons that connect the central nervous system to the rest of the body.

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).

sympathetic nervous system

the division of the autonomic nervous system that arouses the body; mobilizing its energy.

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, characterized by decreased heart rate and increased digestive activity.

sensory neurons

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

motor 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.

endocrine system

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

pituitary gland

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

lesion

tissue destruction; 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.

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.

brain stem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; is responsible for automatic survival functions.

medulla

the base of the brain stem; controls heartbeat and breathing.

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.

limbic System

neural system located below the cerebral hemispheres; associated with emotions and drives.

cerebellum

at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.

amygdala

two lima-bean-sized neural clusters in the limbic system; linked to emotion, especially fear and aggression. It plays a crucial role in processing emotional responses and is involved in the formation of memories related to emotional events.

hypothalamus

it directs several maintenance activities (eating, drinking, body temp.), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

hippocampus

a neural center located in the limbic system; helps process for storage explicit (conscious) memories of facts and events.

Cerebral cortex

the body's ultimate control and information processing center.

frontal lobes

the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.

Parietal lobes

the portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

occipital lobes

the most rearward lobe, contains visual areas that receive and process visual stimuli.

temporal lobes

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.

association areas

areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are 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.

Corpus callosum

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

blind sight

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

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.

heredity

the genetic transfer of characteristics from parent to offspring.

environment

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

genome

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

multiple sclerosis

disease of the central nervous system; inflammation and damage of the protective myelin sheath of nerves, disrupting neural transmission.

myasthenia gravis

an autoimmune disorder in which the body produces antibodies against acetylcholine receptors, causing faulty transmission of nerve impulses at neuromuscular junctions.

Substance P

neurotransmitter that modulates the experience of pain

Broca's area

helps control language expression-an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech.

wernickes area

a brain area involved in language comprehension and expression; usually in the left temporal lobe

aphasia

impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).