What is the Difference Between White Matter and Gray Matter?

The main difference between white matter and gray matter in the brain and spinal cord lies in their composition and function:

• White matter is composed of nerve fibers, also known as axons, which are coated with myelin, a mixture of proteins and lipids that helps conduct nerve signals and protect the axons. White matter is responsible for conducting, processing, and sending nerve signals up and down the spinal cord.
• Gray matter, also known as substantia grisea, is made up of cell bodies, neuronal cell bodies, axon terminals, dendrites, and nerve synapses. Gray matter is essential for receiving information and regulating outgoing information, as it contains the cell bodies of neurons.

In terms of location, gray matter is found in the cerebellum, cerebrum, and brain stem, as well as forming a butterfly-shaped portion of the central spinal cord. White matter, on the other hand, is found closer to the center of the brain, whereas the outer cortex is mainly gray matter. In the spinal cord, white matter is distributed around the central gray matter.

Damage to the white matter can affect a person's ability to move, use their sensory faculties, or react appropriately to external stimuli.

Comparative Table: White Matter vs Gray Matter

Here is a table summarizing the differences between white matter and gray matter:

White matter primarily consists of myelinated axons and serves to transmit signals to other regions of the brain, spinal cord, and body. It is located in the brain and spinal cord and appears white due to the high lipid content of the myelin.

Gray matter, on the other hand, is made up of neuronal cell bodies, glial cells, and unmyelinated axons. It is involved in information processing, computation, and motor control. Gray matter is found in the cerebrum, brain stem, and cerebellum, and is responsible for receiving and regulating outgoing information.