The UC Davis Health System has a helpful way of understanding the difference. It suggests we use a computer analogy and imagine that the gray matter is the actual computer, while white matter is the cables that connect the computer to other devices.

How Gray Matter Is Affected by Dementia

Research studies have found a correlation between people who have dementia and reduced gray matter volume in the brain. In people with Alzheimer’s disease, the hippocampus, in particular, is noted to experience atrophy.

One study compared the volume of gray matter in the brains of participants with Alzheimer’s disease to those with Lewy body dementia. They found that, while the gray matter was reduced in Lewy body dementia when compared to cognitively normal people, it was significantly less reduced when compared to those with Alzheimer’s disease.

Can You Change the Volume of Gray Matter in Your Brain?

Several interesting studies have been conducted on the amount of gray matter in your brain. One showed a correlation between speaking more than one language and a higher amount of gray matter in the brain. This seems to reinforce previous research findings that demonstrate a protective benefit against the symptoms of Alzheimer’s in people who are multi-lingual.

A second study concluded that higher levels of physical activity and cardiovascular fitness levels were correlated with increases in the volume of gray matter in the brain.

A third study noted an increase in the density of gray matter in people who participated once a week in eight sessions of mindfulness meditation trainings. While the number of participants was small at 17, the resulting increase in gray matter thickness was significant.