What is it?

• The central nervous system is made up of two types of tissue: the grey matter and the white matter.
• The brain’s grey matter is the tissue in the central nervous system that consists of nerve cells, and cells that are responsible for generating sensation and motor control.
• The loss of grey matter in memory-related regions of the brain may in turn increase the risk of developing dementia in the longer term
• The grey matter serves to process information in the brain. Structures within the grey matter process signals generated in the sensory organs or other areas of the grey matter. This tissue directs sensory (motor) stimuli to nerve cells in the central nervous system where synapses induce a response to the stimuli. These signals reach the grey matter through myelinated axons that make up the bulk of the white matter in the cerebrum, cerebellum and spine.
• The white matter makes up axons, which are the wiring connecting grey matter tissue.
  • (Axons are the processes that extend from neuronal cell bodies, carrying signals between those bodies)
• Myelin forms a protective coating around these axons, insulating them and improving their transmission of neuronal signals.

Why in News?

• A study conducted by scientists at the University of Oxford, the Imperial College London, in the U.K. and the National Institutes of Health, U.S.A.  found that there is distinct loss of grey matter, in regions of the brain associated with smell and taste in those who had tested positive for the coronavirus compared to those who hadn’t.

 Reference:

1. https://www.thehindu.com/sci-tech/health/study-finds-loss-in-grey-matter-after-coronavirus-infection/article34936719.ece