BOSTON, Mass. — While some age more gracefully than others, many people will experience a certain degree of mental deterioration as the decades pass. A small collection of “SuperAgers,” however, display the memory skills of a 25-year-old well into old age. Now, scientists from Massachusetts General Hospital have identified the neural activity behind these SuperAgers’ memory advantages.
“This is the first time we have images of the function of superagers’ brains as they actively learn and remember new information,” says senior study author Alexandra Touroutoglou, PhD, director of Imaging Operations at MGH’s Frontotemporal Disorders Unit, in a media release.
Back in 2016, Dr. Touroutoglou and her team had identified a small group of older adults (65+) showing incredible performances on memory tests for their age brackets. Today, those same individuals are participants in an ongoing study of aging taking place at MGH.
“Using MRI, we found that the structure of superagers’ brains and the connectivity of their neural networks more closely resemble the brains of young adults; superagers had avoided the brain atrophy typically seen in older adults,” Dr. Touroutoglou explains.
Does vision play a role in memory?
For this latest study, a collection of 40 older adults (average age: 67 years-old) completed a very challenging memory test. While each individual took their test, researchers examined their brains using functional magnetic resonance imaging (fMRI). The use of fMRI over MRI is notable because the former better illustrates the activity of different brain areas during tasks. Meanwhile, another group of 41 younger adults (average age: 25 years-old) took the same test while undergoing fMRI imaging.
While everyone filled out their exam, the research team payed particularly close attention to each person’s visual cortex. That brain region is responsible for processing everything humans see, but can be quite sensitive to the aging process.
“In the visual cortex, there are populations of neurons that are selectively involved in processing different categories of images, such as faces, houses or scenes,” notes lead study author Yuta Katsumi, PhD, a postdoctoral fellow in Psychiatry at MGH. “This selective function of each group of neurons makes them more efficient at processing what you see and creating a distinct memory of those images, which can then easily be retrieved.”
SuperAgers have the memory skills of a kid
As one ages, that selectivity (technically called neural differentiation) tends to deteriorate. As a result, neurons that at one time primarily responded to faces may activate for other visual cues. This makes it much harder for the brain to create unique neural activation patterns for various image categories. In simpler terms, this process of neuronal diminishment is a major reason why it is so common for older adults to have trouble recalling if they’ve read, seen, or eaten something specific in the past.
Incredibly, the fMRI scans performed for this research revealed that the SuperAgers’ memory skills were nearly identical to the 25-year-olds’, and their brains’ visual cortex showed consistent youthful activity patterns.
“The superagers had maintained the same high level of neural differentiation, or selectivity, as a young adult,” Dr. Katsumi adds. “Their brains enabled them to create distinct representations of the different categories of visual information so that they could accurately remember the image-word pairs.”
“An important question that researchers still must answer is whether “superagers’ brains were always more efficient than their peers, or whether, over time, they developed mechanisms to compensate for the decline of the aging brain,” Dr. Touroutoglou concludes.
Prior research has shown that specialized training can indeed increase the selectivity of various brain regions. So, it’s possible that specific interventions or techniques can be developed for normal aging adults to delay or even fully prevent neural differentiation decline. Perhaps one day we can all be SuperAgers.
The study appears in the journal Cerebral Cortex.