After a rat has a spatial experience, like running along a track, it replays the experience in its mind, only backwards. This, according to MIT cognitive scientist Matthew A. Wilson. Previously, Wilson reported that rats also recall waking events when dreaming. How does Wilson know? He monitored the rats' brain activities. Eventually, Wilson says, the same techniques to "eavesdrop on both the sleeping and conscious brain" could help treat memory disorders or even improve memory. From the MIT News Office:
This backward instant replay may play a significant role in reinforcing learning, Wilson said. "Understanding this replay is likely to be critical in understanding how animals — and humans — learn from experience. This phenomenon may constitute a general mechanism of learning and memory…"
Wilson and MIT postdoctoral fellow David J. Foster measured the activity of cells in the rat hippocampus during periods of running and stopping. During each session, each animal ran several laps on familiar and unfamiliar tracks, occasionally stopping for a food reward. After eating, the animal paused to groom its fur, move its whiskers or just stand still before running again. It was during this pause that the reverse replay occurred, and it was most likely to occur when an animal ran an unfamiliar track, supporting the idea that this phenomenon helps the hippocampus reinforce a newly learned task.
