COLUMBUS – You remember seeing your daughter hit a home run in softball, but can’t remember exactly where. You know you took the family to Cedar Point, but can’t remember if it was in 2010 or 2011, or in July or August.
Researchers at OSU may have found the place where those memories have been stored all this time.
For the first time, scientists believe they have evidence of where the brain records times and places of our memories, research they hope will help sufferers of Alzheimer’s disease and other forms of dementia.
“What we’re picking up here is not the whole memory, but the basic gist – the where and when of the experience,” said Per Sederberg, senior author of the study and assistant professor of psychology at Ohio State. “This could be viewed as the memory hub, where we have these general, large-scale representations of our experiences.”
Sederberg conducted the research, published this week in the Proceedings of the National Academy of Sciences, with two OSU colleagues and an Ohio State alumnus now at the University of Newcastle in Australia.
Their study suggests the brain’s left anterior hippocampus records the broad picture of where and when an event took place, that the posterior portion of the hippocampus may “fine-tune” the information, and another part of the brain allows us to recall the memory in detail.
“What we found may be just the targeting mechanism that gives us the general gist of the memory. And then there is a process that moves out through the rest of the hippocampus and spreads out through the cortex as we relive the entirety of the memory,” Sederberg said.
Over the course of one month, the nine women who took part wore smartphones around their necks that were equipped with a ”lifeblogging” app, which took more than 5,000 random photos for each woman at random times of the day, recording the time, location, whether she was moving, and other information.
At the end of the month, the participants were placed in a functional magnetic resonance imaging (fMRI) scanner, which measured activity in their brain while they looked 120 of their own photos for eight seconds apiece while trying to remember the event depicted in each picture and reliving the experience in their mind.
The researchers compared the data from the fMRI scans on pairs of images taken at least 100 meters and 16 hours apart.
Remembering an experience “lights up” many parts of the brain, Sederberg said, and the more different two memories are, the more different the pattern of activity will be while recalling them. Sederberg found that the patterns of activity in the brain’s left anterior hippocampus were more different for memories of events that happened further apart in time and space. The farther apart the memories, the farther apart their representations appeared in the hippocampus, Sederberg said.
Sederberg noted that the hippocampus is one of the first areas of the brain to degrade in Alzheimer’s disease.
Sederberg says he hopes to repeat the study with people of different ages and with people who are showing early signs of dementia to see how their brains are representing their memories.