White matter of the brain
The white matter of the brain contains nerve fibers. Many of these nerve fibers (axons) are surrounded by a type of fat called myelin. The myelin gives the whitish appearance to the white matter. Myelin acts as an insulator, and it increases the speed of transmission of all nerve signals.
References
Bhatia PG, Sklar EML. Neuroimaging: structural neuroimaging. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 36A.
Update Date: 2/16/2011
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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