For the first time, scientists were able to find evidence of where the brain records the time and place of our real-life memories. The results of their research showed the similarity of the brain activation patterns when memories were recalled. This can be considered as an indicator of the breadth of space and time between the actual events.
For the study that was conducted by scientists at the Ohio State University, the participants wore a smartphone around their neck running an app that took random photos for a month. When later on the participants relived memories related to those photos in an fMRI scanner, the research team found that the information about where and when their specific memories occurred is stored on a part of the brain's hippocampus.
The study was published this week in the Proceedings of the National Academy of Sciences. The results showed a correlation between the memories' representations in the hippocampus and the moment in space and time when memories occurred.
According to Per Sederberg, assistant professor of psychology at Ohio State and senior author of the study, what the research team could pick up was not the whole memory, but its basic elements, the where and when of the experience. He explained that this could be viewed as the memory hub, where we store large-scale, general representations of our experiences.
The other lead authors of the study were Simon Dennis, a former Ohio State professor now at the University of Newcastle in Australia and Dylan Nielson, a Ph.D. graduate of Ohio State.
Previously, similar studies have been conducted in rats. The studies have led to the discovery of rat neurons that code for space. The discovery won last year the Nobel Prize in Medicine. Previous studies in humans were also been done. The studies asked the participants to recall lists of words or other information, but they recorded only memories of just a few minutes created under experimental conditions.
This new study expands further on both of those dimensions, by analyzing real-life memories in humans. According to Sederberg, the research team found that the hippocampus represents time and space for memories spanning up to 30 kilometers (19 miles) in space and for a period of at least a month. The lead researcher added that this is the first time when scientists have been able "to study memories on the scale of our lives."
