Thick Cortex Offers Clue to Better Memory

Sharp minds in old age correlated with significantly thicker cortical layers in an area of the brain associated with memory and cognitive performance, investigators reported.

Brain scans of “SuperAgers” (those ages ≥80 with above-average cognitive function) revealed a significantly thicker cerebral cortex and left anterior cingulate cortex, as compared with an age-matched control group. In fact, cortical volume did not differ from that of normal middle-aged adults, as reported online in the Journal of the International Neuropsychological Society.

The SuperAgers performed significantly better than the age-matched control group on a standardized test of memory and at least as well as the middle-age control group, according to Emily Rogalski, PhD, of Northwestern University in Chicago, and co-authors.

“The findings show that memory decline isn’t the only route for the aging brain,” Rogalski told MedPage Today. “It seems there are some unique biologic factors that contribute to super aging, and we looked at one example, the cortex of the brain. There’s a lot more to look at.”

Whether SuperAgers were born with greater cortical volume or resisted age-related cortical atrophy is unclear, she added.

Norms for cognitive function decline with age, such that “normal” for an 80-year-old person is usually markedly lower than the norm for a 50-year-old, particularly on tests of episodic memory. Whether that decline is an inevitability of aging remains unclear, the authors wrote in their introduction.

The age-related decline in cognitive function has outliers, people who retain good memory performance beyond 80. The observation has led to speculation about the existence of an inherent “alternative trajectory” that resists neuroanatomical changes and decline in cognitive function observed in older people.

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