<Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts . 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 . </P> <P> 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 . </P> <P> White matter is composed of bundles, which connect various grey matter areas (the locations of nerve cell bodies) of the brain to each other, and carry nerve impulses between neurons . Myelin acts as an insulator, which allows electrical signals to jump, rather than coursing through the axon, thus increasing the speed of transmission of all nerve signals . </P>

Where is white matter located in the brain and spinal cord