The Effects of “White Matter” in the Brain

When it comes to aging, most of us focus on minimizing decline – slowing memory loss, bolstering sight and hearing, and doing whatever we can to minimize the degradations that come with age. Stanford Center on Longevity Faculty Affiliate Michael Greicius, Assistant Professor of Neurology and Neurological Sciences, takes a different approach.

“Why accept a 30% decline in cognitive function with age?” he asked. “Why not aim for maintaining the brain of a 25-year old?”

This bold question guides Greicius’ research, as he and his team explore the connections between age and reduced brain function and how to prevent or reverse these negative effects of “normal aging.”

Greicius recently conducted a study, funded by a Center on Longevity faculty seed grant, to explore a hypothesized series of connections between white matter lesions (or “hyperintensities”) in the brain and behavioral impairments. These lesions are small areas of altered brain tissue that appear in MRI scans. They are more frequently noticed in the brains of older individuals.

The hypothesis suggests that white matter lesions may lead to disrupted structural connectivity within the brain along what are known as neural “tracks.” These disruptions could then lead to functional deficits, in turn contributing to behavioral impairments. Such declines in function are what many people commonly associate with old age.

Greicius notes that the study produced “enough data to show that [the hypothesis] is plausible,” but that “a true answer would require a sample three times as large.” The course of the project also “helped systematize the process of identifying the location of hyperintensities,” Greicius said, something which carries useful implications for other work on changes of brain function with age. Larger samples of healthy subjects already exist at other labs that should allow researchers to apply the lessons learned here – including a particularly valuable means of tracing tracks within the brain – to future investigations.

“We learned a lot from this seed grant,” said Greicius. Even though the hypothesis remains unproven, the investigation has given researchers a strong base on which to build a comprehensive study. There is still much basic research to be done to reach Grecius’ dream of understanding what it takes to maintain a youthful brain, but the results of this study are clearly a step in the right direction.