
Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Gray matter
Introduction
Grey matter (or gray matter) is a major component of the central nervous system, consisting of nerve cell bodies, glial cells (astroglia and oligodendrocytes), capillaries, and short nerve cell extensions/processes (axons and dendrites).
Composition
Composition
Grey matter is composed of unmyelinated neurons as opposed to white matter (myelinated neurons). It has a grey brown color which comes from the capillary blood vessels and the neuronal cell bodies.
Distribution
Distribution
Grey matter is distributed at the surface of the cerebral hemispheres (cerebral cortex) and of the cerebellum (cerebellar cortex), as well as in the depth of the cerebral (thalamus; hypothalamus; subthalamus, basal ganglia – putamen, globus pallidus, nucleus accumbens; septal nuclei), cerebellar (deep cerebellar nuclei – dentate nucleus, globose nucleus, emboliform nucleus, fastigial nucleus), brainstem (substantia nigra, red nucleus, olivary nuclei, cranial nerve nuclei) and spinal white matter (anterior horn, lateral horn, posterior horn).
Function
Function
The function of grey matter is to route sensory or motor stimulus to interneurons of the CNS in order to create a response to the stimulus through chemical synapse activity. Research has shown that the amount of gray matter in a brain is positively correlated with human intelligence. (Andreason & Others, 1994)
Grey matter structures (cortex, deep nuclei) process information originating in the sensory organs or in other grey matter regions. This information is conveyed via specialized nerve cell extensions (long axons), which form the bulk of the cerebral, cerebellar, and spinal white matter.
Editor-In-Chief: Template:Infobox Anatomy C. Michael Gibson, M.S., M.D. [1]
