Glossary 1

Question 1

Acetylcholine

Answer 1

A critical neurotransmitter that controls functions such as memory, attention, sleep, heart rate, and muscular activity.

Question 2

Action Potential

Answer 2

An electrical charge that travels along the axon to the neuron’s terminal, where it triggers the release of a neurotransmitter. This occurs when a neuron is activated and temporarily reverses the electrical state of its interior membrane from negative to positive.

Question 3

Addiction

Answer 3

Loss of control over drug intake or compulsive seeking and taking of drugs, despite adverse consequences.

Question 4

Adenosine

Answer 4

A neurochemical that inhibits wakefulness, serving the purpose of slowing down cellular activity and diminishing arous¬al. Adenosine levels decrease during sleep.

Question 5

Adrenal Gland

Answer 5

An endocrine organ that secretes hormones. The outer layer (adrenal cortex) secretes the stress hormone cortisol. The inner portion (adrenal medulla) secretes epinephrine and norepinephrine in concert with the activation of the sympathetic nervous system in the “fight or flight” response.

Question 6

Alzheimer’s Disease (AD)

Answer 6

A major cause of dementia in the elderly, this neurodegener¬ative disorder is characterized by the death of neurons in the hippocampus, cerebral cortex, and other brain regions. The earliest symp¬toms of the disease include forgetfulness; dis¬orientation as to time or place; and difficulty with concentration, calculation, language, and judgment. In the final stages, individuals are incapable of self-care and may be bedridden.

Question 7

Amnesia

Answer 7

A memory impairment usually caused by brain damage or disease, or by drugs such as some anesthetics. People with amnesia may be unable to recall events from the past, form new memories, or both.

Question 8

Amygdala

Answer 8

A structure in the forebrain that is an important component of the limbic system and plays a central role in emotional learning, particularly within the context of fear.

Question 9

Amyotrophic Lateral Sclerosis (ALS)

Answer 9

Commonly known as Lou Gehrig’s disease, ALS causes motor neurons in the brain and spinal cord to disintegrate, resulting in loss of control of voluntary muscle movements such as walking.

Question 10

Analgesic

Answer 10

A drug that relieves pain without causing a loss of consciousness.

Question 11

Anxiety

Answer 11

A state of heightened arousal charac¬terized by intense worry.

Question 12

Aphasia

Answer 12

Disturbance in language compre¬hension or production, often as a result of a stroke.

Question 13

Apoptosis

Answer 13

Programmed cell death induced by specialized biochemical pathways, often serving a specific purpose in the development of an animal.

Question 14

Arousal

Answer 14

A physiological state involving changes in the body and brain that motivate behavior and enable response to stimuli.

Question 15

Astrocyte

Answer 15

A star-shaped glial cell in the cen¬tral nervous system that nourishes neurons; regulates the formation, maintenance, and pruning of synapses; and contributes to the blood-brain barrier.

Question 16

Attention

Answer 16

A state of arousal in which the brain’s sensory processing is directed at a limited number of stimuli. Voluntary (en¬dogenous) attention is a conscious decision to focus on a particular stimulus. Involuntary (exogenous) attention is an unplanned focus on a change in the environment, such as a loud noise or sudden movement.

Question 17

Auditory Nerve

Answer 17

A branch of the vestib¬ulocochlear nerve that transmits auditory information from the cochlea of the ear to the brain.

Question 18

Autism Spectrum Disorder (ASD)

Answer 18

A set of conditions characterized, in part, by impaired social communication and inter¬action, and narrow, obsessive interests or repetitive behaviors.

Question 19

Autonomic Nervous System

Answer 19

A part of the peripheral nervous system responsible for regulating the activity of internal organs. It includes the sympathetic and parasympa¬thetic nervous systems.

Question 20

Axon

Answer 20

The fiber-like extension of a neuron by which it sends information to target cells.

Question 21

Axon Terminal

Answer 21

The ends of axons where neurotransmitters are released to target cells.

Question 22

Basal Ganglia

Answer 22

A group of interconnected structures located deep in the brain that play an important role in voluntary movement, motor skill learning, and habits. These struc¬tures include the caudate nucleus, putamen, nucleus accumbens, globus pallidus, and substantia nigra.

Question 23

Benzodiazepines

Answer 23

A class of drugs that en¬hance activity of the brain’s primary inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), to produce sedative and anti-anxiety effects. Benzodiazepines are often prescribed to treat anxiety disorders and insomnia.

Question 24

Blood-Brain Barrier

Answer 24

A protective membrane composed of tightly packed endothelial cells lining the brain’s capillaries and highly special¬ized astrocytes, which controls the passage of certain molecules into and out of the brain.

Question 25

Brain-Derived Neurotrophic Factor (BDNF)

Answer 25

A neurotrophic peptide that supports the growth and survival of neurons.

Question 26

Brainstem

Answer 26

The major route by which the forebrain sends information to and receives information from the spinal cord and pe¬ripheral nerves. The brainstem includes the midbrain, pons, and medulla, and it controls, among other things, respiration and the regu¬lation of heart rhythms.

Question 27

Broca’s Area

Answer 27

A region of the frontal lobe — usually the left hemisphere — that governs speech production.

Question 28

Cell Body

Answer 28

Also called the soma, the part of a neuron that contains the nucleus (with DNA) and the organelles, but not the projections such as the axon or dendrites.

Question 29

Central Nervous System

Answer 29

The brain and spinal cord.

Question 30

Cerebellum

Answer 30

A large structure located at the roof of the hindbrain that helps to control the coordination of movement by making connec¬tions to the pons, medulla, spinal cord, and thalamus. It also may be involved in aspects of motor learning.

Question 31

Cerebral Cortex

Answer 31

The wrinkled, outermost layer of the cerebrum consisting primarily of neuron cell bodies.

Question 32

Cerebellum

Answer 32

A large structure located at the roof of the hindbrain that helps to control the coordination of movement by making connec¬tions to the pons, medulla, spinal cord, and thalamus. It also may be involved in aspects of motor learning.

Question 33

Cerebral Cortex

Answer 33

The wrinkled, outermost layer of the cerebrum consisting primarily of neuron cell bodies.

Question 34

Cerebrum

Answer 34

The largest part of the human brain associated with higher order function¬ing, such as thinking, perceiving, planning, and understanding language, as well as the control of voluntary behavior.

Question 35

Circadian Rhythms

Answer 35

A cycle of behavior or physiological change lasting approximately 24 hours.

Question 36

Cochlea

Answer 36

A snail-shaped, fluid-filled organ of the inner ear responsible for converting sound into electrical potentials to produce an auditory sensation.

Question 37

Cognitive Behavioral Therapy

Answer 37

A form of counseling used to identify and change negative thought patterns that can contribute to anxiety and mood disorders.

Question 38

Cones

Answer 38

A primary receptor cell for vision lo¬cated in the retina. It is sensitive to color and is used primarily for daytime vision.

Question 39

Corpus Callosum

Answer 39

The large bundle of nerve fibers linking the left and right cerebral hemispheres.

Question 40

Cortisol

Answer 40

A hormone manufactured by the ad¬renal cortex. In humans, cortisol is secreted in the greatest quantities before dawn, readying the body for the activities of the coming day.

Question 41

Cranial Nerves

Answer 41

Twelve pairs of nerves that can be seen on the bottom surface of the brain. Some of these nerves transmit sensory infor¬mation; some control the movement of face, head, and neck muscles; others transmit infor¬mation to internal organs to regulate functions such as blood pressure and heart rate.

Question 42

Critical Period

Answer 42

A period of heightened plasticity in brain development when certain experiences and sensory inputs are required for the formation of functional brain circuits.

Question 43

Declarative Memory

Answer 43

Also called explicit memory, a type of memory that can be con¬sciously retrieved. It includes memory of facts (semantic memory) and memory of personal experiences (episodic memory).

Question 44

Default Mode Network

Answer 44

A collection of brain regions activated during quiet rest.

Question 45

Dementia

Answer 45

A decline in cognitive ability that interferes with day-to-day functioning.

Question 46

Dendrite

Answer 46

A treelike extension of the neuron cell body. The dendrite is the primary site for receiving and integrating information from other neurons.

Question 47

Depolarization

Answer 47

A change in a neuron’s membrane potential in which the cytoplasm becomes more positively charged. Neurons must depolarize beyond a certain threshold to generate an action potential.

Question 48

Depression

Answer 48

A psychiatric disorder character¬ized by sadness, hopelessness, pessimism, loss of interest in life, reduced emotional well-being, and abnormalities in sleep, appetite, and energy level.

Question 49

Dopamine

Answer 49

A catecholamine neurotransmit¬ter present in three circuits of the brain: one that regulates movement; a second, thought to be important for cognition and emotion; and a third that regulates the endocrine system. Deficits of dopamine in the motor circuit are associated with Parkinson’s disease. Abnormal¬ities in the second circuit have been implicat¬ed in schizophrenia.

Question 50

Down Syndrome

Answer 50

A condition that results from the presence of an extra copy of chromo¬some 21. This genetic anomaly is associated with physical and developmental characteris¬tics, including mild to moderate intellectual disabilities; low muscle tone; and an increased risk of congenital heart defects, respiratory problems, and digestive tract obstruction.