White matter

The type of neural tissue that facilitates communication between different regions of the brain and spinal cord.

White matter is a crucial component of the central nervous system, primarily composed of myelinated axons, which are nerve fibers covered in a fatty insulating layer known as myelin. This myelin gives white matter its characteristic color. In contrast to gray matter, which is rich in neuronal cell bodies and unmyelinated axons, white matter's primary role revolves around the transmission of signals throughout the brain and spinal cord.

Terminologia Anatomica

substantia alba

System

Nervous system

Function

The primary function of white matter lies in its ability to enable efficient communication between different brain regions and between the brain and spinal cord. It serves as the main conduit for nerve signals, allowing for the rapid transmission of information necessary for coordinated motor functions, sensory processing, and cognitive functions. The speed of these signals is significantly enhanced by myelination, which acts like insulation, helping to prevent the loss of electrical signals during transmission. In essence, white matter acts as the wiring of the nervous system, facilitating complex interactions that underlie everything from reflexes to advanced reasoning skills.

Location

White matter is strategically located beneath the cortex of the brain, surrounding the gray matter, which contains the neuronal cell bodies. In humans, the largest concentrations of white matter can be found in the cerebral hemispheres, where it interconnects different areas of the brain, including the frontal, parietal, temporal, and occipital lobes. Additionally, white matter extends throughout the spinal cord, where it serves as the primary pathway for communication between the brain and peripheral nervous system, forming crucial tracts that relay sensory and motor information.

Did You Know?

White matter constitutes nearly half of the human brain's total volume.
Myelination in white matter occurs progressively throughout early development and is a key factor in improving cognitive functions as a person matures.
Certain neurological diseases, such as multiple sclerosis, specifically damage white matter, leading to disruptions in nerve signal transmission.