Why some older adults have better memories than others

Newly published research shows why some older adults remember better than others. The answer has to do with how much hippocampal activity is occurring.

The findings were conducted by Alexandra Trelle, a postdoctoral research fellow at Stanford University, and her colleges. The team built on studies that have focused on young populations and looked into memory and recall in healthy, older adults as part of the Stanford Aging and Memory Study. The results were published late last month in eLife.

“Some individuals exhibit remarkable maintenance of memory function throughout late adulthood, whereas others experience significant memory decline,” Trelle said in a press release. “Studying these differences across individuals is critical for understanding the complexities of brain aging, including how to promote resilience and longevity.”

In the experiment, lead author Trelle and the team gathered 100 participants between the ages of 60 and 82. As the participants studied words associated with pictures of famous people and places, their brains were scanned. Then, their brains were scanned as they took a memory test in which they were prompted with previously viewed words and asked to remember the picture paired with it.

The test was created to evaluate each participant’s ability to recall specific links between parts of an event. This form of memory is frequently disproportionately affected by aging.

Upon analyzing the scans, researchers saw the brain processes that support remembering in older adults look like those in younger people. What they saw showed that there was an increase in hippocampal activity — the hippocampus is the part of the brain mainly associated with memory — and the reinstatement of activity patterns in the cortex that were there when people first experienced the event.

“It was striking that we were able to replicate this moment-to-moment relationship between hippocampal activity, replay in the cortex, and memory recall, which has previously been observed only in healthy younger adults,” Trelle said. “In fact, we could predict whether or not an individual would remember at a given moment in time based on the information carried in patterns of brain activity.”

On average, the ability to remember declined with age, according to the findings. But regardless of age, stronger hippocampal activity and replay in the cortex was associated with better performing memory.

The research is part of the first steps for future probes into the Stanford Aging and Memory Study cohort’s research on older adults’ memory. Ultimately, the goal is to be able to identify people who are at increased risk for Alzheimer’s disease.