The tissue called "gray matter" in the brain and spinal cord is also known as substantia grisea, and is made up of cell bodies. "White matter", or substantia alba, is composed of nerve fibers.
Review Date 2/4/2020
Updated by: Amit M. Shelat, DO, FACP, FAAN, Attending Neurologist and Assistant Professor of Clinical Neurology, Stony Brook University School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.