What do your brain patterns say about you?
There’s two types of people in the world: those who will remember each and every detail about a past experience, and those who pretty much only remember that it happened. Detail-rich memory styles are known as episodic memory, while remembering the facts without details is called semantic memory.
For the first time, a team of researchers from the Rotman Research Institute at Baycrest Health Sciences has shown that these two memory styles are associated with distinct brain connectivity patterns, and these connectivity patterns may suggest a lifelong “memory trait.”
"For decades, nearly all research on memory and brain function has treated people as the same, averaging across individuals," said lead investigator Dr. Signy Sheldon, now an assistant professor of Psychology at McGill University. "Yet as we know from experience and from comparing our recollection to others, peoples' memory traits vary. Our study shows that these memory traits correspond to stable differences in brain function, even when we are not asking people to perform memory tasks while in the scanner."
The study consisted of a survey as well as brain scans. 66 healthy young adults (the average age was 24) first completed online questionnaires called the Survey of Autobiographical Memory (SAM). They described how well they remember autobiographical events and facts, and there was a wide variety of memory capabilities within the group. The responses fell between the extremes of those with Highly Superior Autobiographical Memory (HSAM) or Severely Deficient Autobiographical Memory (SDAM).
After completing the survey, the researchers scanned the brains of the 66 participants with resting state fMRI. The brain scans revealed high levels of connectivity between the memory center of the brain (the medial temporal lobes) and either the visual parts of the brain (in those with episodic memory) or the areas in the front of the brain associated with organizing and reasoning (in those with semantic memory).
Photo courtesy of Baycrest
In the wake of these findings, the researchers are interested in whether these two distinct memory styles are related to brain health in the elderly years. Specifically, could certain memory traits protect the brain from age-related cognitive decline in later years, or at least delay it?
"With aging and early dementia, one of the first things that people notice is difficulty retrieving the details of events," senior study author Dr. Brian Levine, a senior scientist at Baycrest's Rotman Research Institute and professor of Psychology at the University of Toronto, said in a press release.
"Yet no one has looked at how this relates to memory traits. People who are used to retrieving richly-detailed memories may be very sensitive to subtle memory changes as they age, whereas those who rely on a factual approach may prove to be more resistant to such changes," he said.
Now that memory traits have been associated with distinct brain patterns, follow-up studies are currently being conducted to determine whether memory traits relate to personality, genetics, and psychiatric conditions like depression. Perhaps our memory styles say much more about us than previously thought.