We’ve all been there: in the middle of a midterm, staring down blankly at question #17. You know you know the answer, but for some reason, it just is not coming to you. Memory fails you. Well, rest assured that the next time a situation like this occurs, there may be just a single cell to blame. A recent study conducted by scientists at UCLA and the Weizmann Institute of Science in Israel found that individual brain cells are responsible for free recall, or the retrieval of a memory without any prompting or clues. In the study, the subjects watched video clips of familiar landmarks and people, like the characters from the “Simpsons,” and were later asked to recall and discuss any of the clips. As the researchers monitored the brain activity in the hippocampus, the area of the brain responsible for memory, they found that the same single brain cells lit up when watching a clip as when the subject recalled that specific clip later.
A study of rodents found that a similar phenomenon happened in these animals as well. As the rodent passed certain spots in a maze, special cells in the hippocampus involved with location became active, and the rat’s next turn could be predicted. The results of these studies show that the same brain cells which were initially activated during the creation of a memory are the same cells that become active during recall of the memory. However, it should be noted that this may not always be the case, since the circuitry of memories can be reworked. Although one brain cell was found to fire most rapidly, the recall of the memory requires the workings of large memory circuits.
What is most interesting about these findings is that they suggest a deep connection between remembering and reliving an experience. When we think back to an event from out past, it may trigger the same neurons that were activated at the time of the event. Now if only we could just tell our neurons to relive that instant in class that might shed some light on that tricky question #17…
University of California – Los Angeles (2008, September 16). How Memories Are Made, And Recalled. ScienceDaily. Retrieved October 7, 2008, from http://www.sciencedaily.com /releases/2008/09/080908101651.htm
Carey, Benedict (2008, September 4). “For the Brain, Remembering is Reliving.” The New Yok Times. Retrieved October 4, 2008, from http://www.nytimes.com/2008/09/05/science/05brain.html.