There is new evidence that memories are stored in the same neurons that experienced the memory in the first place. Although this sounds expected—researchers have assumed this for some time—this is the first study that actually demonstrates it.
Their Method:
These researchers implanted tiny electrodes into the brains of epilepsy patients (specifically in the hippocampus, which is known for its role in memory formation and recall). This process sounds horrific, but has become largely standard procedure for patients undergoing surgery for epilepsy. As a result, experimenters have a small window before surgery where they are able to perform unprecedented research on human subjects. In this case, they had patients watch short video clips, pause to think about them for a minute, and report which clips they recalled.
Their Finding:
Nearly everyone remembered the clips, but more surprising was that brain cells that were active while the clip was playing became active again during recall! “In fact, the cells became active a second or two before people were conscious of the memory, which signaled to researchers the memory to come.” (Source: NYTimes)
Their Conclusion:
From the New York Times article:
Though it did not address this longer-term process, the new study suggests that at least some of the neurons that fire when a distant memory comes to mind are those that were most active back when it
happened, however long ago that was.“The exciting thing about this,” said Dr. Kahana, the University of Pennsylvania professor, “is that it gives us direct biological evidence of what before was almost entirely theoretical.”
