Relive your old memories

Innovation in Observing Brain Cells
Benedict Carey
nytimes.com, september 4, 2008

Have you ever watched a t.v show that you had loved when you were younger and had gotten a familiar feeling? A similar feeling to what you had had before? Scientists are on the verge of discovering that when recalling a memory the same neurons react in the same way as they had in the original experience. This experience almost takes you back in time to relive the moments that happened in the past.

Things that you found more interesting, and that you had more of a connection to, are going to stay in your memory longer than something that you don't have a connection to. This is because your connection to the experience causes neurons to react with more activity because of emotion and personal interest.

In this article, scientists did an experiment in which they threaded electrodes into the brains of 13 people with epilepsy and had them watch several 5-10 second film clips and observed the active cells during the clips. Every person they examined had at least one film clip in which the neurons responded with lots of activity. They also all had at least one film clip that the neuron activity was weak.

After a short distraction the researchers asked the patients to recall the memories on some of the clips, and they noted that the initial cell reaction to the clips was the same as the reaction when recalling the clip. The cells reacted 2 - 3 seconds before the memory was recalled so the scientists could predict the memory before the person got it.

In class we discussed the enlightenment, and some of the concepts that came about in that period of time. One concept was that a theory should be tested and evidence gathered before it was accepted as "true". In the article it states, "...these spontaneous memories reside in some of the same neurons that fired most furiously when the recalled event had been experienced. Researchers had long theorized as much but until now had only indirect evidence. " This made me think that before the enlightenment because before this proof concept, indirect evidence may have been enough for people to accept this concept as true, and that experimenting may not have been necessary.