tract(redirected from ascending tract)
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Related to ascending tract: corticospinal tract
in the central nervous system, any one of several groups of closely placed nerve fibers having a common morphological structure and common functions. Tracts are divided by function into associative tracts, which unite various sections of the cerebral cortex in the same hemisphere; commisural tracts, which connect both hemispheres and ensure their cooperative activity; and projection tracts, which unite the cerebral cortex with lower brain formations and, through them, with the periphery.