Glossary

• Acetylcholine is a critical neurotransmitter that controls functions such as memory, attention, sleep, heart rate, and muscular activity
• Action Potential is an electrical charge that travels along the axon to the neuron's terminal, triggering the release of a neurotransmitter
• Addiction is the loss of control over drug intake or compulsive seeking and taking of drugs, despite adverse consequences
• Adenosine is a neurochemical that inhibits wakefulness, slowing down cellular activity and diminishing arousal. Adenosine levels decrease during sleep
• Adrenal Gland is an endocrine organ that secretes hormones. The outer layer (adrenal cortex) secretes the stress hormone cortisol, while 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
• Alzheimer's Disease (AD) is a major cause of dementia in the elderly, characterized by the death of neurons in the hippocampus, cerebral cortex, and other brain regions. Symptoms include forgetfulness, disorientation, difficulty with concentration, calculation, language, and judgment. In the final stages, individuals are incapable of self-care and may be bedridden
• Amnesia is 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
• Amygdala is 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
• Amyotrophic Lateral Sclerosis (ALS), commonly known as Lou Gehrig's disease, causes motor neurons in the brain and spinal cord to disintegrate, resulting in loss of control of voluntary muscle movements such as walking
• Analgesic is a drug that relieves pain without causing a loss of consciousness
• Anxiety is a state of heightened arousal characterized by intense worry
• Aphasia is a disturbance in language comprehension or production, often as a result of a stroke
• Apoptosis is programmed cell death induced by specialized biochemical pathways, often serving a specific purpose in the development of an animal
• Arousal is a physiological state involving changes in the body and brain that motivate behavior and enable response to stimuli
• Astrocyte is a star-shaped glial cell in the central nervous system that nourishes neurons; regulates the formation, maintenance, and pruning of synapses; and contributes to the blood-brain barrier
• Attention is a state of arousal in which the brain's sensory processing is directed at a limited number of stimuli. Voluntary (endogenous) 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
• Attention Deficit Hyperactivity Disorder (ADHD) is a condition characterized by excessively inattentive, hyperactive, or impulsive behaviors
• Auditory Nerve is a branch of the vestibulocochlear nerve that transmits auditory information from the cochlea of the ear to the brain
• Autism Spectrum Disorder (ASD) is a set of conditions characterized, in part, by impaired social communication and interaction, and narrow, obsessive interests or repetitive behaviors
• Autonomic Nervous System is a part of the peripheral nervous system responsible for regulating the activity of internal organs. It includes the sympathetic and parasympathetic branches
• Autonomic Nervous System: responsible for regulating the activity of internal organs
• Includes the sympathetic and parasympathetic nervous systems
• Axon: fiber-like extension of a neuron that sends information to target cells
• Axon Terminal: ends of axons where neurotransmitters are released to target cells
• Basal Ganglia: interconnected structures in the brain that play a role in voluntary movement, motor skill learning, and habits

  • Includes the caudate nucleus, putamen, nucleus accumbens, globus pallidus, and substantia nigra
• Benzodiazepines: drugs that enhance the activity of the brain's primary inhibitory neurotransmitter, GABA, to produce sedative and anti-anxiety effects

  • Often prescribed to treat anxiety disorders and insomnia
• Blood-Brain Barrier: protective membrane composed of tightly packed endothelial cells lining the brain's capillaries and specialized astrocytes, which control the passage of certain molecules into and out of the brain
• Brain Waves: oscillating patterns of brain activity that can be detected and recorded using electroencephalography (EEG)
• Brain-Derived Neurotrophic Factor (BDNF): a neurotrophic peptide that supports the growth and survival of neurons
• Brainstem: major route through which the forebrain sends information to and receives information from the spinal cord and peripheral nerves

  • Includes the midbrain, pons, and medulla, and controls, among other things, respiration and the regulation of heart rhythms
• Broca's Area: region of the frontal lobe, usually in the left hemisphere, that governs speech production
• Cell Body: 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
• Central Nervous System: the brain and spinal cord
• Cerebellum: large structure located at the roof of the hindbrain that helps to control the coordination of movement by making connections to the pons, medulla, spinal cord, and thalamus

  • Also may be involved in aspects of motor learning
• Cerebral Cortex: the wrinkled, outermost layer of the cerebrum consisting primarily of neuron cell bodies
• Cerebrum: the largest part of the human brain associated with higher order functioning, such as thinking, perceiving, planning, and understanding language, as well as the control of voluntary behavior
• Circadian Rhythms: a cycle of behavior or physiological change lasting approximately 24 hours
• Computational Neuroscience: a field of neuroscience research that uses computer programs and algorithms to analyze information about the brain and develops mathematical models to explain brain function
• Corpus Callosum: the large bundle of nerve fibers linking the left and right cerebral hemispheres
• Cortisol: a hormone manufactured by the adrenal cortex

  • In humans, cortisol is secreted in the greatest quantities before dawn, readying the body for the activities of the coming day