It’s common to forget some things with age, but a select group of elderly people retain an unusually remarkable memory, recalling episodes from their past with a clarity that matches a much younger person’s. These people—also called super-agers—might hold a key to fighting memory issues associated with age.
Now, scientists say super-agers can accomplish their feats of memory due to larger-than-average neurons in the brain area responsible for recollection.
In a new study published Friday in The Journal of Neuroscience, researchers imaged the brains of six super-agers who had, during their lives, taken part in ongoing research into their abilities. The super-agers sampled died at an average of 91 years old. The researchers compared those brains to those of seven cognitively average elderly people who had died after 80; six younger people who died at 49, on average; and five people who had early Alzheimer’s.
“To understand how and why people may be resistant to developing Alzheimer’s disease, it is important to closely investigate the postmortem brains of super-agers,” lead author Tamar Gefen, an academic clinical neuropsychologist at Northwestern University’s Feinberg School of Medicine, says in a statement. “What makes super-agers’ brains unique? How can we harness their biologic traits to help elderly stave off Alzheimer’s disease?”
The “significantly larger” neurons of super-agers could provide a clue. Some of their brain cells in the entorhinal cortex, an area involved in memory, were larger even than those of individuals who were 20 to 30 years their juniors, per the study.
Compared to cognitively normal elderly individuals, super-agers also had less accumulation of a protein called tau inside their neurons. Buildup of tau and another protein is a typical sign of Alzheimer’s.
“[The overall study] adds to the growing evidence that super-agers differ from typical adults on multiple levels of the brain,” Alexandra Touroutoglou, a neurology researcher at Harvard Medical School who was not involved with the study, tells New Scientist’s Carissa Wong. “The sample size here is relatively small, but that’s understandable. Super-agers are a rare group, so finding a good number of them in a postmortem brain study is difficult.”
The research suggests that neurons without tau tangles can remain large and healthy. Neurons that do have the tangle of protein, however, might shrink.
Still, the way that super-agers get these larger, tau tangle-free neurons remains a mystery.
“We need to study their genetics, lifestyle factors and educational attainment,” Gefen tells BBC News’ Michelle Roberts. “We also need to capture their history and personal narratives.”
Rosa Sancho, head of research at Alzheimer’s Research U.K., tells BBC News that studying super-agers could eventually help lead to the development of new treatments for dementia.
“Further research will need to uncover exactly what causes these super-ager brain cells to be larger and better protected,” she tells the publication. “For example, is it a genetic feature super-agers are born with, and if so, what features?”