part of part of composed primarily of central nervous system white matter AEO:0000139 AEO:0001011 CNS tract/commissure CNS tracts and commissures CNS white matter Cell part cluster consisting predominantly of neurites in the brain and the spinal cord[FMA:83929]. EMAPA:35927 FMA:83929 HBA:9218 MA:0001135 Multi-tissue structure comprised largely of myelinated axons.[TAO] Neural tissue consisting of myelinated axons connecting grey matter areas of the central nervous system. OpenCyc:Mx4rwOAsDZwpEbGdrcN5Y29ycA PBA:294022044 TAO:0000145 TAO:0002142 TAO:0002143 The myelination of axons by glial cells was the last major step in the evolution of cells in the vertebrate nervous system, and white-matter tracts are key to the architecture of the mammalian brain.[well established][VHOG] UBERON:0002316 UMLS:C0682708 VHOG:0001764 ZFA:0001682 neuronal white matter nlx_anat_101177 seems to have been lost in the transition from NIFGA to Neurolex substantia alba uberon white mater white matter of neuraxis white substance myelinated nerve fiber central nervous system cell part cluster