Nerve tissue which is of a dark grey colour and forms part of the central nervous system.
Those parts of the brain and spinal cord that comprise mainly the interconnected and tightly packed nuclei of neurons (nerve cells). The tissue is darker than that of the white matter, which is made of axons from the nerve cells. In the brain, grey matter is mainly found in the outer layers of the cerebrum, which is the zone responsible for advanced mental functions. The inner core of the spinal cord is made up of grey matter.
The central nervous system contains regions primarily composed of densely clustered and interconnected nerve cell bodies, along with their branching dendrites. These regions are responsible for processing and integrating information. In contrast, the axons of nerve cells, which transmit nerve impulses, form the white matter of the central nervous system.
Grey matter is predominantly located in the outer layers of the cerebrum, the primary part of the brain responsible for complex mental functions. It is also found in deeper brain regions like the basal ganglia. Additionally, grey matter constitutes the central portion of the spinal cord.