Grey matter意思

"Grey matter" is a term used in anatomy and neuroscience to refer to the areas of the central nervous system (CNS) that are made up of neuronal cell bodies, unmyelinated fibers, and glial cells. It is also known as "gray matter" or "grey substance." The term "grey matter" comes from the fact that it appears grey in color due to the presence of these cell bodies, which are darker than the white matter but lighter than the surrounding tissues.

In contrast, "white matter" is composed mainly of myelinated axons (nerve fibers) that connect different parts of the grey matter within the CNS. The myelin sheaths around the axons appear white due to their high lipid content.

Grey matter is found in the brain and the spinal cord. In the brain, it is concentrated in the cerebral cortex, which is responsible for higher cognitive functions such as perception, memory, and decision-making. It is also found in the hippocampus, which is involved in memory formation, and the thalamus, which plays a role in relaying sensory information to the cortex.

The density and distribution of grey matter can vary across different regions of the brain, and changes in grey matter structure or volume have been associated with a variety of neurological and psychiatric conditions. For example, studies have shown that certain brain disorders, such as Alzheimer's disease and schizophrenia, are associated with abnormalities in grey matter structure or function.