White matter

White matter
White matter
	Micrograph showing white matter with its characteristic fine meshwork-like appearance (left of image – lighter shade of pink) and grey matter, with the characteristic neuronal cell bodies (right of image – dark shade of pink). HPS stain.
	Human brain right dissected lateral view, showing grey matter (the darker outer parts), and white matter (the inner and prominently whiter parts).
Details
Location	Central nervous system
Identifiers
Latin	substantia alba
MeSH	D066127
TA98	A14.1.00.009; A14.1.02.024; A14.1.02.201; A14.1.04.101; A14.1.05.102; A14.1.05.302; A14.1.06.201
TA2	5366
FMA	83929
	Anatomical terminology

White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts.^[1] Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution of action potentials, acting as a relay and coordinating communication between different brain regions.^[2]

White matter is named for its relatively light appearance resulting from the lipid content of myelin. However, the tissue of the freshly cut brain appears pinkish-white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries. Its white color in prepared specimens is due to its usual preservation in formaldehyde.

^ Blumenfeld, Hal (2010). Neuroanatomy through clinical cases (2nd ed.). Sunderland, Mass.: Sinauer Associates. p. 21. ISBN 978-0878936137. Areas of the CNS made up mainly of myelinated axons are called white matter.
^ Douglas Fields, R. (2008). "White Matter Matters". Scientific American. 298 (3): 54–61. Bibcode:2008SciAm.298c..54D. doi:10.1038/scientificamerican0308-54.

[1] Blumenfeld, Hal (2010). Neuroanatomy through clinical cases (2nd ed.). Sunderland, Mass.: Sinauer Associates. p. 21. ISBN 978-0878936137. Areas of the CNS made up mainly of myelinated axons are called white matter.

[2] Douglas Fields, R. (2008). "White Matter Matters". Scientific American. 298 (3): 54–61. Bibcode:2008SciAm.298c..54D. doi:10.1038/scientificamerican0308-54.

[1]

[2]