white matter

parts of the nervous system composed of nerve fibers that are enclosed in a myelin sheath, which gives a white coloration to otherwise grayish neural structures. The sheaths cover only the fibers, so regions containing mainly cell bodies are gray. Compare gray matter.

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Psychology term of the day

July 27th 2024

trinucleotide repeat

a contiguous repetition of the same three nucleotides within a nucleic acid (DNA or RNA). The occurrence of extra trinucleotide repeats in certain genes causes dysfunction, inluding Huntington’s disease and fragile X syndrome.