White Matter in the Brain
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Medically reviewed by Brian M. Snelling, MD
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 also explains the role of white matter disease on memory and dementia.
Related:How Your Brain Works
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.
Related: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
While white matter disease has been associated with strokes, cognitive loss, and dementia, it also has some physical and emotional symptoms such as balance problems, falls, depression, and difficulty multitasking (e.g., walking and talking).
Related:Understanding Migraine-Related Brain Lesions on Your MRI
Increasing and Improving White Matter
Some research has found that physical exercise, aerobic activities and weight resistance training in particular, was correlated with improved white matter integrity in the brains of those who participated in those studies.
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.
Several studies have supported following the Mediterranean Diet, with its focus on healthy fats, vegetables, fruits, nuts, and fatty fish, as a way to improve white matter.
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.
Related:Meditation for People With Cancer
Summary
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.
