White matter

What is it?

Like grey matter, white matter is part of the central nervous system. It enables fast and efficient communication between different areas of the brain and spinal cord — it acts as a network of highways along which electrical signals travel.

What are its functions?

White matter is found in the deepest areas of the brain and connects different areas of the cerebral cortex to other internal structures, such as the basal ganglia and thalamus, which help control movement, coordination, sleep or reception of sensory information. Healthy white matter is therefore essential for transmitting information between multiple areas of the brain, supporting crucial functions including walking, learning and decision-making.

In the spinal cord, the white matter is located on the outside and plays a key role in transmitting signals between the brain and the rest of the body. It is responsible for carrying sensory information from the body to the brain and for transmitting motor commands from the brain to the muscles, allowing movement and other bodily functions.

Importance for health

White matter is essential to the nervous system as it ensures efficient communication between different areas. Its deterioration is associated with several diseases, including psychiatric and neurodegenerative disorders. In conditions such as multiple sclerosis, damage to white matter slows down or interrupts the transmission of nerve signals, causing motor problems, fatigue, thinking difficulties and loss of coordination. White matter changes have also been observed in diseases such as Parkinson’s disease, Alzheimer’s disease or psychosis.

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