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developmental program by which a neuron kills itself at a certain age unless inhibited from doing so


formation of the axon and dendrites that gives a neuron its distinctive shape

fetal alcohol syndrome

condition resulting from prenatal exposure to alcohol and marked by decreased alertness, hyperactivity, varying degrees of mental retardation, motor problems, heart defects, and facial abnormalities

focal hand dystonia

"musician's cramp", a condition in which the touch responses to one finger overlap those of another, leading to clumsiness, fatigue, and involuntary movements


movement of neurons toward their eventual destinations in the brain


development of a myelin sheath that insulates an axon

nerve growth factor

protein that promotes the survival and growth of axons in the sympathetic nervous system and certain axons in the brain


chemical that promotes the survival and activity of neurons


production of new cells

stem cells

undifferentiated cells that can divide and produce daughter cells that develop more specialized porperties


formation of synapses

closed head injury

sharp blow to the head resulting from a fall, an automobile or motorcycle accident, an assault, or other sudden trauma that does not actually puncture the brain

collateral sprout

newly formed branch from an uninjured axon that attaches to a synapse vacated when another axon was destroyed

denervation supersensitivity

increased sensitivity by a postsynaptic cell after removal of an axon that formerly innervated it


decreased activity of surviving neurons after other neurons are damaged

disuse supersensitivity

increased sensitivity by a postsynaptic cell because of decreased input by incoming axons


accumulation of fluids


rupture of an artery


local insufficiency of blood because a blood clot or other obstruction has closed an artery


area of endangered cells surrounding an area of primary damage

phantom limb

continuing sensation of an amputated body part


(cerebrovascular accident) temporary loss of normal blood flow to a brain area

tissue plasminogen activator (tPA)

drug that breaks up blood clots


to remove or disable the sensory nerves from a body part

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