The brain is an incredibly intricate and complex organ. However, dividing it into the left and right hemispheres, and identifying the regions as different lobes –the parietal, temporal, occipital, and frontal — helps simplify and understand its anatomical structure. Another common way to classify the brain is by distinguishing it into grey and white matter. But what exactly are these, and how do they differ?
“Grey matter refers to the areas of the brain primarily composed of neuronal cell bodies and dendrites, which form the brain’s information processing centres,” says Dr Hard Vasavada, a senior consulting neurosurgeon at Sterling Hospital, Gujarat. It appears grey in colour due to the abundance of cell bodies and lacks myelin — a fatty substance that coats nerve fibres, he explains. Grey matter plays a crucial role in cognition, memory, perception, and decision-making processes.
Whereas white matter consists of nerve fibres, called axons, coated with myelin. The myelin gives the white matter its whitish appearance and is like an insulated wire enhancing the transmission speed of electrical signals. “White matter acts as the brain’s communication network, enabling the efficient transfer of information between various grey matter regions,” says Dr Vasavada.
Grey matter is responsible for the brain’s higher-order functions, while white matter facilitates the connections that allow these functions to run smoothly. Both structures are interdependent and crucial for proper brain function.
The below infographic highlights some key aspects of the grey and white matter.
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Editor’s note – This Infographic is second of a series of articles for World Brain Day (22 July)
