By Dr Ananya Mandal, MD
Grey matter makes up a substantial part of the central nervous system. Grey matter is where the majority of the brain’s neuronal cell bodies are located.
The brain contains both grey and white matter. While the grey matter contains many neural cell bodies and few myelinated axons, the white matter contains many myelinated axons and very few cell bodies. The white matter is so named based on the white color of myelin. Apart from nerve cell bodies, myelin also contains dendrites, glial cells and capillaries. The grey matter is light grey with hues of pink and yellow from the neuronal cell bodies and capillaries.
Grey matter is found mainly in the brain, where it is located in the following regions:
- The surface of the cerebral hemispheres.
- The surface of the cerebellum or the cerebellar cortex.
- Deep within the cerebrum in the hypothalamus, thalamus, subthalamus, basal ganglia, globus pallidus, putamen, septal nuclei, nucleus accumbens.
- Deep within the cerebellar in the dentate nucleus, emboliform nucleus, fastigial nucleus and globose nucleus.
- In the brainstem in the red nucleus, olivary nuclei, substantia nigra and the cranial nerve nuclei.
- In the spinal grey matter including the anterior horn, the lateral horn and the posterior horn.
The grey matter serves to process information in the brain. While the information reaches the grey matter in the form of nerve signals that are carried along nerve fibres, it is the grey matter that processes this information.
Reviewed by Sally Robertson, BSc
Last Updated: Sep 8, 2014