Grey matter

What is it?

Grey matter, like white matter, is part of the central nervous system. It is responsible for processing information and controlling functions such as thought, movement and sensation; it acts as a control centre that analyses signals and generates responses.

What are its functions?

In the brain, grey matter is mainly found in the cerebral cortex, the outermost layer, which is responsible for higher functions such as thinking, memory, language and consciousness. It is also found in deeper areas such as the basal ganglia and thalamus, which are involved in controlling movement and sensation.

In the spinal cord, grey matter is located in the centre, shaped like an ‘H’ or a butterfly. It regulates automatic reflexes, such as pulling your hand away when you touch something hot, and acts as a link for signals to travel between the brain and the body.

The importance of grey matter for health

The state of grey matter is key to the proper functioning of the brain. Changes in its structure or volume are associated with several neurological and psychiatric diseases. For example, Alzheimer’s disease causes a progressive loss of grey matter, affecting memory, language and reasoning.

Both white and grey matter can change over time. Exercise, learning and an active social life can help maintain their integrity, while ageing, chronic stress and some diseases can cause them to deteriorate.