Friends have remarked that I have a particularly good memory. I can vividly recall seemingly unmemorable events from childhood, the exact outfits my husband and I were wearing when we met and details from casual conversations that occurred more than a decade ago. But my ability to remember pales in comparison to a select group of people who can recall aspects of nearly every day of their lives.
Such individuals, who have what researchers call a "highly superior autobiographical memory" (HSAM), often say that their memories play like scenes from a movie in their mind. In an effort to gain a greater insight into how our brain create memories and why some health conditions cause them to deteriorate, researchers at UC Irvine are extensively studying this select group of people's phenomenal gift to remember. New Scientist reports [login required]:
One theory concerns emotions. Research on animals and humans has shown that if strong emotions accompany an event, then the details can be seared into memory - a process in which the amygdalae, small almond-shaped structures next to each hippocampus, are involved. [UC Irvine researcher James McGaugh, PhD,] says HSAMers may differ in the way their brains process emotional arousal. "It's possible that they are operating at such a high level of arousal that all this extra stuff just gets sucked into memory," he says. "But we don't know."
The emotional arousal theory has been lent credence by a recent paper from a team at Vanderbilt University in Nashville, Tennessee - the only other group to have published work on an HSAMer. An MRI scan revealed that their subject has a right amygdala about 20 per cent larger than normal, as well as heightened connectivity between that side's amygdala and hippocampus ( Neurocase, DOI: 10.1080/13554794.2011.654225). "It is possible that the enlarged amygdala is overcharging information somehow, making it more relevant and easier to remember," says neurologist Brandon Ally, who led the work.
In addition to the connection to emotions, there's evidence suggesting that having an extraordinary memory may be linked to what researchers define as an "obsessive-like or compulsive-like" behavior. The article explains more.
Previously: Using light to activate memories in mice, Gene variation predicts age-related mental decline and Fear leads to creation of new neurons, new emotional memories
Photo by Neil Webb, Wellcome Images