<Tr> <Th> FMA </Th> <Td> 83929 </Td> </Tr> <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>

Why is white matter on the inside of the brain