white matter

noun, Anatomy

nerve tissue, especially of the brain and spinal cord, which primarily contains myelinated fibers and is nearly white in color.

Compare gray matter (def 1).

Origin

1830-40

Examples from the web for white matter

Scientists have suspected for more than two decades that schizophrenia is linked to defects in the brain's white matter.
Brain scans show that as people get older, the white matter typically degenerates.
They found that the white matter in the prefrontal cortex of chimpanzees does not grow as rapidly as it does in humans.
The white matter in the foremost frontal lobes, the so-called prefrontal areas, had been disrupted on both sides of the brain.
These myelin-coated tracts make up the brain's white matter, while the bodies of neural cells are called grey matter.

British Dictionary definitions for white matter

white matter

noun

the whitish tissue of the brain and spinal cord, consisting mainly of myelinated nerve fibres Technical name substantia alba Compare grey matter

white matter in Medicine

white matter n.
Whitish nerve tissue, especially of the brain and spinal cord, chiefly composed of myelinated nerve fibers and containing few or no neuronal cell bodies or dendrites. Also called alba, substantia alba, white substance.

white matter in Science

white matter
The whitish tissue of the vertebrate brain and spinal cord, made up chiefly of nerve fibers (axons) covered in myelin sheaths. Compare gray matter.