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White matter of the brain

White matter is found in the deeper tissues of the brain (subcortical). It contains nerve fibers (axons), which are extensions of nerve cells (neurons). Many of these nerve fibers are surrounded by a type of sheath or covering called myelin. Myelin gives the white matter its color. It also protects the nerve fibers from injury. Also, it improves the speed and transmission of electrical nerve signals along extensions of the nerve cells called axons.

By comparison, gray matter is tissue found on the surface of the brain (cortical). It contains the cell bodies of neurons, which give gray matter its color.

References

Calabresi PA. Multiple sclerosis and demyelinating conditions of the central nervous system. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 411.

Ransom BR, Goldberg MP, Arai K, Baltan S. White matter pathophysiology. In: Grotta JC, Albers GW, Broderick JP, et al, eds. Stroke: Pathophysiology, Diagnosis, and Management. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 9.

Wen HT, Rhoton AL, Mussi ACM. Surgical anatomy of the brain. In: Winn HR, ed. Youmans and Winn Neurological Surgery. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 2.

Review Date 2/28/2019

Updated by: Alireza Minagar, MD, MBA, Professor, Department of Neurology, LSU Health Sciences Center, Shreveport, LA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.