How is memory formed and recreated?

What is memory made of? One thing is for sure, the cells in the brain.

For the first time scientists from UCLA, Weizman Institute of Science in Israel have recorded the activity of recreating the memory of single brain cells, thereby revealing the location of specific memory storage in the brain. At the same time, explain why the brain can recreate memories.

Online publication in Science, Dr. Itzhak Fried, author of the study and professor of neurosurgery at UCLA, and his colleagues recorded the activity of hundreds of different neurons that make up Memory in the brain of 13 epilepsy patients receiving surgery at UCLA Medical Center.

Surgeons put electrodes in the patient's brain before surgery. Fried also took advantage of electrodes to record neuron activity when memories were being formed.

The patient was shown a few short video clips, which included pictures of landmarks and people, along with clips of Jerry Seinfeld, Tom Cruise, Homer Simpsons characters in the movie 'Simpsons Family' and other characters. When patients see, the researchers recorded the activity of many neurons in the hippocampus region and a nearby area known as the inner cortex (entorhinal cortex) can react strongly. with small clips.

Only a few minutes after the interleaving operation, the patient was asked to reproduce any clips that appeared in their heads.

Fried said: 'They are not forced to recall a specific clip but they are free to choose, which is any clip that appears in their head.'

Images represent neural neuron activity.Scientists have documented the activity of hundreds of neurons that make up memory.(Photo: iStockphoto / Sebastian Kaulitzki)

The researchers found that neurons that responded to a specific clip in the previous period simultaneously lit one or two seconds before the patient recounted the clip they remembered. However, the neurons are not lit when other clips are recalled. Basically, the researchers can tell which clips the patient remembers before the patient speaks.

Fried stresses that individual neurons are recorded as they glow, they do not work alone, but they are part of a much larger memory cycle that involves hundreds of thousands of cells involved in the reaction. with the clip.

According to him, this study is very significant because it first confirmed that spontaneous memory arises through the activity of the same neurons that glow when memories are first formed. Sometimes scientists have doubted and established the hypothesis of the relationship between re-activating neurons in the mollusc region and the conscious reproduction of past experiences, but this study is now provided direct evidence for the existence of that relationship.

Fried said, 'Accordingly, the recall of past experiences in our memory is the revival of past neuron activity.'

Other authors of the study include Hagar Gelbard - Sagiv, Michal Haral and Rafael Malach of the Weizmann Institute, a scholar of the late Dr. Roy Mukamel of UCLA University. The research was funded by the National Institute of Neurological Disorders and Stroke, the Israel Science Foundation and the US-Israel Science Foundation.

Refer:

Hagar Gelbard-Sagiv, Roy Mukamel, Michal Harel, Rafael Malach, and Itzhak Fried.Internally Generated Reactivation of Single Neurons in Human Hippocampus During Free Recall.Science, 2008;DOI: 10.1126 / science.1164685