As we get older, we start to think a little bit more slowly, we are less able to multitask and our ability to remember things gets a little wobblier. This cognitive transformation is linked to a steady, widespread thinning of the cortex, the brain's outermost layer. Yet the change is not inevitable. So-called super agers retain their good memory and thicker cortex as they age, a recent study suggests.
Researchers believe that studying what makes super agers different could help unlock the secrets to healthy brain aging and improve our understanding of what happens when that process goes awry. “Looking at successful aging could provide us with biomarkers for predicting resilience and for things that might go wrong in people with age-related diseases like Alzheimer's and dementia,” says study co-author Alexandra Touroutoglou, a neuroscientist at Harvard Medical School.
Touroutoglou and her team gave standard recall tests to a group of 40 participants between the ages of 60 and 80 and 41 participants aged 18 to 35. Among the older participants, 17 performed as well as or better than adults four to five decades younger. When the researchers looked at MRI scans of the super agers' brains, they found that their brains not only functioned more like young brains, they also looked very similar.
Two brain networks in particular seemed to be protected from shrinking: the default mode network, which helps to store and recall new information, and the salience network, which is associated with directing attention and identifying important details. In fact, the thicker these regions were, the better the super agers' memory was.
The results, which were published in September 2016 in the Journal of Neuroscience, corroborate previous research that shows these regions are critical communication hubs in the brain. The findings do not explain why super agers have these thicker cortical regions, although most likely it is a combination of genetic factors and a healthy way of life.
If confirmed by other studies, the discovery of shrink-resistant brain regions in super agers could provide a target for future research on aging-related brain changes, says Emily Rogalski, a cognitive neuroscientist at Northwestern University who also studies super agers but was not involved in the new study. She notes that “we will be better able to investigate the cellular, molecular and genetic mechanisms that keep super agers' cortices thicker” and their minds shipshape.