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Memory researchers have made an exciting discovery: the brain takes a different neural path to storing experiences than retrieving memories. Neuroscientists at MIT were able to prove this hitherto unknown "detour". "This study addresses one of the most fundamental questions of memory research, namely how episodic memories are stored and recalled. And it gives us an unexpected answer: There are different ways to store and retrieve, "says Susuma Tonegawa, director of the Riken-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory. The results of the study were published in the online edition of Cell .

In the brain, the hippocampus is primarily responsible for memory. However, a small area in the hippocampus has hardly been studied so far, the so-called subiculum. The picture above shows the neurons of the subiculum in green, the hippocampus neurons in red.

Researchers around Tonegawa have now scrutinized this area, but not in humans, but in mice. For this purpose, their neurons in the subiculum were genetically engineered so that they can be switched on and off by light. For the experiments, the researchers placed the mice in a special chamber and administered a mild electric shock to induce anxiety. When the rodents were brought back into the chamber, they remembered the anxiety situation and responded accordingly.

In one part of the mice, the researchers now switched off the neurons of the subiculum before the anxiety experience. These mice still remembered the experiment later. In the remaining mice, the researchers did not deactivate the subiculum neurons until they had scared the animals. These mice could not remember the experience. As a result, Tonegawa and his team concluded that memories of the subiculum are retrieved but not stored in this way. display

With their results, the researchers wanted to contribute to the study of Alzheimer's. Tonegawa's lab found out a year ago that while the disease is still stored at an early stage of the disease, it can not be retrieved. Now it seems obvious that the subiculum plays a role.

Photo: Dheeraj Roy / Tonegawa Lab, MIT

© - Ruth Roebuck
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