Early research on the sharpest octogenarians reveals unusually youthful brain regions
A nasty affliction sets into humans as they advance in years. The hair either disappears or thins into a fuzzy halo, the skin sags and bunches, while inside the brain, changes set in that slow our reaction times and cause our memories to fade. A steady, widespread thinning out of the brain’s cortex, the outermost layer of the brain, is thought to underlie some of this cognitive transformation.
But not everybody ages the same way—and not everyone, it turns out, suffers from memory decline and cortical thinning. The 48 octogenarians in the Northwestern University Super Aging Project were selected for having met or bested the average performance of a 50- or 60-year old on standard tests of recall. Magnetic resonance imaging scans of their brains corroborate their superior abilities: not only do super agers act the same as their younger counterparts, their brains look the same. “To see no change whatsoever was really surprising,” says Theresa Harrison, one of the researchers who presented preliminary findings from the project at a poster session at the 2011 Society for Neuroscience conference.
In addition to comparing the brains of the high-performing octogenarians to subjects in their fifties and sixties, the researchers also looked at cognitively average individuals in their 80s. These people showed a significant loss of gray matter compared with both middle-aged subjects and the super agers.
One region stood out, however. The super agers appeared to have a much thicker left anterior cingulate cortex than both comparison groups. The anterior cingulate cortex is generally known for its role in error detection, attention, and motivation, but its role in maintaining cognition in elderly individuals remains unexplored.
As with any unpublished data, the research here comes with major caveats. The data presented so far reflected observations from only 12 subjects; the rest are still being analyzed. In addition, the project, led by principle investigator Emily Rogalski, has not yet explored what the anterior cingulate cortex might be doing. The next steps will be to compare the connectivity between brain regions in super agers and control subjects, as well as to search for genetic factors that might explain what distinguishes these individuals.
The lifestyles maintained by the super agers seem to hint at genetic rather than environmental roots. At least superficially, they appear to be nothing alike one another beyond possessing the memory of an individual two or three decades younger. According to Harrison, one participant wears high heels every day, drinks whiskey each night, has outlived four husbands—and survived the Holocaust. Another octogenarian spent her life as a soft-spoken housewife, contracted cancer, and went through chemotherapy. Some super agers never graduated from high school, others are highly accomplished academics. Certain participants have smoked for most of their lives; at least one has stuck to a longtime diet of organic food. Some participants are on more than a dozen medications while others are taking none.
That lifestyle choices appear to have played a small role in these individuals’ cognitive aging could be seen as bad news for those of us not endowed with whatever genetic witches’ brew the lucky few possess. Or it could be the first step in the search for pharmacological interventions that go beyond the usual longevity game plan of maintaining a healthy diet, exercising regularly, and staying socially engaged. However you interpret it, though, you can’t help but love these James Dean Methuselahs, who manage to thumb their noses at the system and ride off into the sunset, brains firing on all cylinders.
Managing Editor, Scientific American Mind