U2 - Biological Bases of Behavior

Module 09 - Biological Psychology and Neurotransmission

neuron

a nerve cell; the basic building block of the nervous system. (Myers Psychology for AP 3e p. 81)

cell body

the part of a neuron that contains the nucleus; the cell's life-support center. (Myers Psychology for AP 3e p. 82)

dendrites

a neuron's often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body. (Myers Psychology for AP 3e p. 82)

axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands. (Myers Psychology for AP 3e p. 82)

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. (Myers Psychology for AP 3e p. 82)

glial cells (glia)

cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory. (Myers Psychology for AP 3e p. 82)

action potential

a neural impulse; a brief electrical charge that travels down an axon. (Myers Psychology for AP 3e p. 83)

threshold

the level of stimulation required to trigger a neural impulse. (Myers Psychology for AP 3e p. 83)

refractory period

(1) 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. (2) in human sexuality, a resting period that occurs after orgasm, during which a person cannot achieve another orgasm. (Myers Psychology for AP 3e pp. 83, 420)

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing. (Myers Psychology for AP 3e p. 83)

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. (Myers Psychology for AP 3e p. 85)

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. (Myers Psychology for AP 3e p. 85)

reuptake

a neurotransmitter's reabsorption by the sending neuron. (Myers Psychology for AP 3e p. 86)

endorphins

"morphine within"—natural, opiate-like neurotransmitters linked to pain control and to pleasure. (Myers Psychology for AP 3e p. 88)

agonist

a molecule that increases a neurotransmitter's action. (Myers Psychology for AP 3e p. 88)

antagonist

a molecule that inhibits or blocks a neurotransmitter's action. (Myers Psychology for AP 3e p. 89)

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems. (Myers Psychology for AP 3e p. 91)

central nervous system (CNS)

the brain and spinal cord. (Myers Psychology for AP 3e p. 92)

peripheral nervous system (PNS)

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body. (Myers Psychology for AP 3e p. 92)

sensory (afferent) neurons

neurons that carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord. (Myers Psychology for AP 3e p. 92)

motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands. (Myers Psychology for AP 3e p. 92)

interneurons

neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs. (Myers Psychology for AP 3e p. 92)

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system. (Myers Psychology for AP 3e p. 92)

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. (Myers Psychology for AP 3e p. 93)

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy. (Myers Psychology for AP 3e p. 92)

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy. (Myers Psychology for AP 3e p. 93)

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response. (Myers Psychology for AP 3e p. 94)

endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream. (Myers Psychology for AP 3e p. 95)

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues. (Myers Psychology for AP 3e p. 95)

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. (Myers Psychology for AP 3e p. 95)

pituitary gland

the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands. (Myers Psychology for AP 3e p. 96)

lesion

tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue. (Myers Psychology for AP 3e p. 98)

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. (Myers Psychology for AP 3e p. 99)

MEG (magnetoencephalography)

a brain imaging technique that measures magnetic fields from the brain's natural electrical activity. (Myers Psychology for AP 3e p. 99)

CT (computed tomography) 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.) (Myers Psychology for AP 3e p. 99)

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. (Myers Psychology for AP 3e p. 99)

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy. (Myers Psychology for AP 3e p. 99)

fMRI (functional MRI)

a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure. (Myers Psychology for AP 3e p. 100)

brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions. (Myers Psychology for AP 3e p. 102)

medulla

the base of the brainstem; controls heartbeat and breathing. (Myers Psychology for AP 3e p. 102)

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. (Myers Psychology for AP 3e p. 102)

reticular formation

a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal. (Myers Psychology for AP 3e p. 102)

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. (Myers Psychology for AP 3e p. 103)

limbic system

neural system (including the amygdala, hypothalamus, and hippocampus) located below the cerebral hemispheres; associated with emotions and drives. (Myers Psychology for AP 3e p. 104)

amygdala

two lima-bean-sized neural clusters in the limbic system; linked to emotion. (Myers Psychology for AP 3e p. 104)

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. (Myers Psychology for AP 3e p. 104)

hippocampus

a neural center located in the limbic system; helps process for storage explicit (conscious) memories of facts and events. (Myers Psychology for AP 3e pp. 106, 340)

cerebral cortex

the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center. (Myers Psychology for AP 3e p. 109)

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. (Myers Psychology for AP 3e p. 109)

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. (Myers Psychology for AP 3e p. 109)

occipital lobes

the portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields. (Myers Psychology for AP 3e p. 110)

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. (Myers Psychology for AP 3e p. 110)

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements. (Myers Psychology for AP 3e p. 110)

somatosensory cortex

an area at the front of the parietal lobes that registers and processes body touch and movement sensations. (Myers Psychology for AP 3e p. 113)

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. (Myers Psychology for AP 3e p. 114)

plasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience. (Myers Psychology for AP 3e p. 116)

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them. (Myers Psychology for AP 3e p. 120)

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. (Myers Psychology for AP 3e p. 121)

consciousness

our subjective awareness of ourselves and our environment. (Myers Psychology for AP 3e pp. 123, 224)

cognitive neuroscience

the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language). (Myers Psychology for AP 3e pp. 13, 124)

dual processing

the principle that information is often simultaneously processed on separate conscious and unconscious tracks. (Myers Psychology for AP 3e p. 125)

blindsight

a condition in which a person can respond to a visual stimulus without consciously experiencing it. (Myers Psychology for AP 3e p. 125)

parallel processing

processing many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions. (Myers Psychology for AP 3e pp. 126, 183, 329)

sequential processing

processing one aspect of a problem at a time; generally used to process new information or to solve difficult problems. (Myers Psychology for AP 3e p. 126)

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior. (Myers Psychology for AP 3e pp. 14, 129)

heredity

the genetic transfer of characteristics from parents to offspring. (Myers Psychology for AP 3e p. 129)

environment

every nongenetic influence, from prenatal nutrition to the people and things around us. (Myers Psychology for AP 3e p. 129)

fraternal (dizygotic) twins

develop from separate fertilized eggs. They are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment. (Myers Psychology for AP 3e p. 132)

interaction

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity). (Myers Psychology for AP 3e p. 137)

evolutionary psychology

the study of the evolution of behavior and the mind, using principles of natural selection. (Myers Psychology for AP 3e pp. 14, 141)

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. (Myers Psychology for AP 3e pp. 14, 141)

mutation

a random error in gene replication that leads to a change. (Myers Psychology for AP 3e p. 142)

consciousness

our subjective awareness of ourselves and our environment. (Myers Psychology for AP 3e pp. 123, 224)

hypnosis

a social interaction in which one person (the hypnotist) suggests to another (the subject) that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur. (Myers Psychology for AP 3e p. 225)

posthypnotic suggestion

a suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized; used by some clinicians to help control undesired symptoms and behaviors. (Myers Psychology for AP 3e p. 226)

dissociation

a split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others. (Myers Psychology for AP 3e p. 227)

circadian rhythm

our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle. (Myers Psychology for AP 3e p. 231)

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. (Myers Psychology for AP 3e p. 232)

alpha waves

the relatively slow brain waves of a relaxed, awake state. (Myers Psychology for AP 3e p. 232)

NREM sleep

non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep. (Myers Psychology for AP 3e p. 233)

hallucinations

false sensory experiences, such as seeing something in the absence of an external visual stimulus. (Myers Psychology for AP 3e pp. 233, 699)

hypnagogic sensations

bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep. (Myers Psychology for AP 3e p. 233)

delta waves

the large, slow brain waves associated with the deep sleep of NREM-3. (Myers Psychology for AP 3e p. 234)

suprachiasmatic nucleus (SCN)

a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of sleepiness. (Myers Psychology for AP 3e p. 235)

insomnia

recurring problems in falling or staying asleep. (Myers Psychology for AP 3e p. 244)

narcolepsy

a sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times. (Myers Psychology for AP 3e p. 245)

sleep apnea

a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings. (Myers Psychology for AP 3e p. 245)

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. (Myers Psychology for AP 3e p. 246)

dream

a sequence of images, emotions, and thoughts passing through a sleeping person's mind. (Myers Psychology for AP 3e p. 247)

manifest content

according to Freud, the symbolic, remembered story line of a dream (as distinct from its latent, or hidden, content). (Myers Psychology for AP 3e p. 248)

latent content

according to Freud, the underlying meaning of a dream (as distinct from its manifest content). (Myers Psychology for AP 3e p. 248)

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation. (Myers Psychology for AP 3e p. 251)

psychoactive drug

a chemical substance that alters perceptions and moods. (Myers Psychology for AP 3e p. 253)

substance use disorder

a disorder characterized by continued substance craving and use despite significant life disruption and/or physical risk. (Myers Psychology for AP 3e p. 253)

tolerance

the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect. (Myers Psychology for AP 3e p. 254)

withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior. (Myers Psychology for AP 3e p. 254)

depressants

drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions. (Myers Psychology for AP 3e p. 255)

barbiturates

drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgment. (Myers Psychology for AP 3e p. 257)

opiates

opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety. (Myers Psychology for AP 3e p. 257)