White Matter in the Brain

White matter provides connections between the different parts of the brain. The brain is made up of a mixture of grey matter and white matter. White matter is found in the deeper tissues known as the subcortical area.

If you think of the brain as a computer system, the gray matter is the hardware, and the white matter is the cables connecting the network and transmitting signals.

This article discusses white matter in the brain and the conditions that impact it. It explains the role of white matter disease on memory and dementia.

What Is White Matter?

White matter in the brain contains nerve fibers (axons), which are surrounded by a protective fatty covering called the myelin sheath. The myelin is what gives white matter its white color.

White matter axons connect nerve cells (neurons). Myelin speeds up the signals between the cells, enabling the brain cells to quickly send and receive messages. It also provides insulation for the fibers, preventing the brain from short-circuiting.

Alzheimer's and White Matter

Some research using imaging studies has found abnormalities in people's white matter prior to the development of Alzheimer's disease symptoms.

Research has also demonstrated the presence of white matter lesions prior to mild cognitive impairment, a condition that carries an increased risk for Alzheimer's disease.

White Matter Disease

White matter hyperintensities, or white matter disease, is a term used to describe spots in the brain that show up on magnetic resonance imaging (MRIs) as bright white areas. These areas may indicate some type of injury to the brain, perhaps due to decreased blood flow in that area.

The presence of white matter hyperintensities has been correlated with a higher risk of stroke, which can lead to vascular dementia.

Initially, white matter disease was thought to simply be related to aging. However, we now know there are other specific risk factors for white matter disease, which include:

• High blood pressure
• Smoking
• Cardiovascular disease
• High cholesterol 

Increasing and Improving White Matter

Some research has found that physical exercise, in particular, cardiorespiratory activities and weight resistance training, was correlated with improved white matter integrity in the brains of those who participated in those studies.

Physical exercise has also been connected to a decreased risk of dementia as well as a slower cognitive decline in people who have already been diagnosed with Alzheimer's or another kind of dementia.

Other research found that when adults learned new skills, the amount of white matter in their brains increased. This was true for learning to read as an adult and learning to juggle.

Additionally, white matter increased relative to the number of hours that professional musicians practiced their instruments.

White matter functioning was also improved by the practice of meditation, and the difference was observed in as little as two to four weeks.

A Word from Verywell

Historically, science hasn't paid as much attention to our brain's white matter as its gray matter.

We now know, however, how important white matter is to our overall brain health and cognitive ability, as well as how declines in white matter are correlated with impairments in brain functioning.

Research shows exercise, mental activity, and meditation can improve the health of your body and brain.