AP PSYCH UNIT 2

Dendrites

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

Axon

the neuron extension that passes messages through its branches to other neurons or to 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.

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

in neural processing, 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-nothing 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. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

Neurotransmitters

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

Endorphins

"morphine within"-natural, opiate-like neurotransmitters linked to pain control and to pleasure.

Agonist

a molecule that increases a neurotransmitter's action.

Antagonist

a molecule that inhibits or blocks a neurotransmitter's action.

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.

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

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 muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

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, conserving its energy.

reflex

a simple, automatic response to a sensory stimulus, such as the 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

a 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

the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Lesion

tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue.

EEG

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

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

CT 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. (Also called CAT scan).

PET scan

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

MRI

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

fMRI

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

terminal buttons

The branched end of the axon that contains neurotransmitters.

Acetylcholine (ACh)

Enables muscle action, learning, and memory. With Alzheimer's disease, ACh-producing neurons deteriorate.

Dopamine

A neurotransmitter associated with movement, attention, learning, emotion, and the brain's pleasure and reward system.

Serotonin

A neurotransmitter that affects hunger, sleep, arousal, and mood.

Norepinephrine

A neurotransmitter involved in arousal, control, alertness, learning, and mood regulation

GABA

A major inhibitory neurotransmitter in the brain.

neural network

networks of nerve cells that integrate sensory input and motor output

Medulla

the base of the brainstem; controls heartbeat and breathing.

Thalamus

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

Reticular Formation

a nerve network that travels through the brainstem into the thalamus and plays and 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, and enabling nonverbal learning and memory.

Amygdala

two lima-bean-sized neural clusters in the limbic system; linked to emotion.

Hypothalamus

a neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), 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 intricate fabric of interconnected neural cells covering the cerebral hemispheres; 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 judgements

Parietal Lobes

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

Occipital Lobes

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

Temporal Lobes

the portion of the cerebral cortex lying roughly above the ears; including 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

Sensory 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 two brain hemispheres and carrying messages between them

Consciousness

our subjective awareness of ourselves and our environment

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. They 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. The heritability of a trait may vary, depending on the range of populations and environments studied.

Epigenetics

"above" or "in addition to" (epi) genetics; 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 and organism to survive and reproduce in a particular environment will (in competition with other trait variations) most likely be passed on to succeeding generations

Circadian Rhythm

our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.

REM Sleep

rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.

Alpha Waves

the relatively slow brain waves of a relaxed, awake state

NREM Sleep

non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.

Hallucinations

false sensory experiences, such as seeing something in the absence of an external visual stimulus.

Delta Waves

the large, slow brain waves associated with the deep sleep of NREM-3

Insomnia

recurring problems in falling or staying asleep

Narcolepsy

a sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep often at inopportune times.

Sleep Apnea

a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.

Night Terrors

a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during NREM-3 sleep, within two or three hours of falling asleep, and are seldom remembered.

Manifest Content

according to Freud, the symbolic, remembered story line of a dream (as distinct from its latent, or hidden, content)

Latent Content

according to Freud, the underlying meaning of a dream (as distinct from its manifest content).

REM Rebound

the tendency for REM sleep to increase following REM sleep deprivation

Psychoactive Drug

a chemical substance that alters perceptions and moods.

Tolerance

the diminishing effect with regular use of the same dose of drug, requiring the user to take larger and larger doses before experiencing the drug's effect

Withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior

Genes

the biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein

behavioral geneticists

study the role played by our genes and our environment in mental ability, emotional stability, temperament, personality, interests, etc.; they look at the causes of our individual differences

Gazzaniga and Sperry

Worked with split brain patients who had their corpus callosum severed.

neurogenesis

the development of new neurons

aphasia

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

sleep spindles

Short bursts of brain activity that characterize stage 2 NREM sleep.

Broca's area

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

Wernicke's area

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

brain lateralization

The organization of the brain into right and left hemispheres, with each hemisphere performing unique and specialized functions

Freud's wish fulfillment theory

Dreams provide a "psychic safety valve"—expressing otherwise unacceptable feelings; contain manifest (remembered) content and a deeper layer of latent content—a hidden meaning.

activation synthesis theory

a theory of dreaming; this theory proposes that the brain tries to make sense of random brain activity that occurs during sleep by synthesizing the activity with stored memories

information processing theory

a perspective that compares human thinking processes, by analogy, to computer analysis of data, including sensory input, connections, stored memories, and output

Pons

A brain structure that relays information from the cerebellum to the rest of the brain