A new study by researchers at UPenn reveals that the hippocampus not only stores our memories, but it also “geotags” them.
In the experiment, participants played a videogame in a virtual town where they were asked to deliver objects to stores. Once the participant delivered the object, he would learn what the object was, and then be given the next assignment. When asked later to recall which objects were delivered, the part of the participant’s brain associated with the memory of the store was activated, meaning that the memory of the object was inextricably linked to the location.
It’s a little confusing, but very fascinating how the researchers were able to actually determine this. First, they would let the participant roam around the virtual world, and the researchers would note which cells inside the participant’s hippocampus were activated as the participant visited each store. By the end of the roaming, the researchers had a neural map of the participant’s hippocampus, where they knew which cells represented which stores, such that by recalling a specific store, the researchers could detect electrical activity in the neural cell associated with that store. The neural map would look something like this:
After the participants delivered the objects to the stores, these neural cells not only activated when the participant remembered the store, but also when the participant remembered the object delivered to the store. Essentially, the participant had geotagged the location in his brain, much like our phones can automatically geotag the specific location of a picture we take. Pretty cool, huh? This helps explain why I cannot help but think of the place where I first experienced a taste or smell when I recall that sensation; for example, I cannot recall the smell of fish sauce without picturing the kitchen in my house in Ho Chi Minh City, Vietnam. Somewhere in my brain must be a tiny neural cell that represents that kitchen, and it lights up at the mention of fish sauce.
So remember that the hippocampus is the little cartographer inside us all, recording our memories while connecting them with the specific places where we experienced them.
You can read the full article here: http://www.upenn.edu/pennnews/news/memories-are-geotagged-spatial-information-penn-researchers-say