Superseniors, people aged eighty and older with exceptionally good memories, may have larger than normal brain cells in a brain region that is important for memory.
Memory gradually declines with age, but some people can remember a remarkable amount until they are 80 or older. Their memory is comparable to that of people twenty to thirty years younger. In such super-seniors, the brains seem to shrink less than in other elderly people, previous research suggests. Now researchers have shown that these people have larger brain cells in their entorhinal cortex, part of the brain’s memory system.
super seniors
The team of neuropsychologist Tamar Gefen of Northwestern University in Illinois imaged the brains of six super seniors who died at an average age of 91 years. These six previously participated in research into super seniors.
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The images were compared with those of seven people who died at an average age of 89 years, and with those of six people who died at an average age of 49 years. All of these people had memory capacities that are considered normal for their age.
In the superseniors, the brain cells in their entorhinal cortex were about 10 percent larger than those of the people who died at a similar age with normal memory. In fact, the brain cells of the super seniors were about 5 percent larger than those of the people who died forty years younger. This suggests that above-average brain cells can contribute to exceptional memory at age 80 or older.
The super seniors also had significantly fewer protein clumps, called tau tangles, in their brain cells than people who died at a similar age. One of the suspected causes of Alzheimer’s disease is an abnormal construction of the tau protein.
Tau tangles
“I’m not sure why bigger brain cells go together with better memory, other than that they may be more resistant to tau tangles,” Gefen says. ‘Another hypothesis is that they are structurally more stable and generate more optimal connections between brain cells.’
“This study adds to the growing evidence that the brains of superseniors differ from those of ordinary adults in several ways,” said neurological researcher Alexandra Touroutoglou of Harvard Medical School in the United States. ‘The sample size is relatively small, but that is understandable. Superseniors are a rare group, so it’s difficult to examine many of them in a postmortem brain study,” she says.
According to psychiatrist Joseph Andreano, also of Harvard, it has been shown that other brain regions related to mental abilities are also different in size in superseniors. It’s unclear whether the size of brain cells in the entorhinal cortex is specifically responsible for better memory, he says.