Now, Where Was I?

In an experiment by Foster and Wilson (2006), researchers placed a rat into a long narrow corridor and taught it to walk down to each end, where it would find a treat. The rat repeated this, and it enjoyed the treat. It was being fed, after all. But researchers noticed something unusual. The rat would get to one end, eat its treat, then just stop and sit there for a moment. When the researchers plotted the activity of “place cells” (which, in theory fire according to where the rat is in a particular environment) in the rat’s hippocampus, they exhibited bursts of activity when the rat was stationary. The researches expanded a split second’s worth of this strange firing:

You can see that there is successive activation from place cell #19-#1. What they found was that the rat’s brain was actually firing the place cells in such a way that it was repeating the course it had just run, and repeating it backwards. It was as if the mouse was thinking “ok, I just got this treat by walking down this hallway…how did I get here? Where was I?” Perhaps even more interesting is that when the rat was asleep, it continued to do this, except much much faster, theoretically because it was redoing what it had learned but without physical limitations; it could walk down that corridor as fast as its neurons allowed it.

About the author

Ian Park

Ian graduated from Wesleyan University in May 2011 with a degree in Neuroscience and Behavior. In that same year, he was Director of Photography of a senior documentary thesis film at Wesleyan, which won first place. He recently acted as Director of Photography on a Clinique commercial for a competition--it won honorable mentions. He is currently working as a producer/director/editor of video and other digital content in Soho, NY, as well as working on a soon-to-be-released web series, "Postponed."

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