The brain is an immensely complex structure, but there are ways we can divide up its anatomical structure into more discrete parts; the left and right hemisphere, parietal, temporal, occipital and frontal lobes. Another common divider is to separate the brain’s gray and white matter.

Here are a few facts about gray matter :

• The grey matter serves to process information in the brain.
• Grey matter contains most of the brain’s neuronal cell bodies.
• The grey matter includes regions of the brain involved in muscle control, and sensory perception such as seeing and hearing, memory, emotions, speech, decision making, and self-control.
• Almost 95% of the oxygen that the brain absorbs goes to its gray matter, rest goes to its white matter.
• The amount of gray matter areas in the brain may more strongly correlate to a higher IQ than the overall size of the brain.
• While there are essentially no disparities in general intelligence among men and women, men do have 6.5 times the amount of gray matter that women.
• Pathological liars have a deficit of gray matter.
• Chronic alcoholics typically have a reduced volume of gray matter.
• Children with autism have more gray matter in their brains than healthy children.
• One study suggests meditation may increase gray matter.
• Gray matter consists of neutrons, the brain’s nerve cells.
• Gray matter, the thinking part of the brain, grows throughout childhood.
• Older smokers lose gray matter and cognitive function at a greater rate than non smokers.
• Gray matter is distributed at the surface of the cerebral hemispheres, the cerebellum, in the depths of the cerebrum, brainstem and spinal gray matter.

Reference : https://www.brainscape.com/blog/wp-content/uploads/2012/03/Gray-Matter.png