People With Better Memory May Have More Choosy Neurons

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Royal
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People With Better Memory May Have More Choosy Neurons

Post by Royal » Sat Jul 16, 2016 2:31 am

People With Better Memory May Have More Choosy Neurons

How good your memory is might depend on how picky your nerve cells are. In a new study, scientists found that people who do well on a memory test have more neurons that are very precise about when they decide to fire compared with people who perform poorly.

Previous studies have found single neurons that seem to only fire in response to something specific, such as an image of a particular celebrity or a famous monument (since photographs of actors Jennifer Aniston and Halle Berry were used in the first experiments, these cells are sometimes called after the celebrities). These neurons fired to different images of the same celebrity, leading researchers to conclude that there might be single neurons in the brain coding for a "concept."

In the new study, researchers in the United States and Europe wanted to know if any of our neurons can get more specific, and discriminate between pictures of the same celebrity.

It's normally difficult to spy on individual neurons, because putting in the electrodes that read their activity is so invasive. But the researchers were able to recruit 25 people with severe epilepsy who needed to have electrodes implanted in their temporal lobe to identify areas that might respond to surgical treatment.

Each participant viewed pictures of famous people, such as Bill Clinton or Anne Hathaway. They were then shown blocks of images that included ones they had seen already, other pictures of the same person and photos of different famous people (for example, George W. Bush). For each image, the participants pressed a button to indicate whether they had seen it before.

All of the participants had neurons in the temporal lobe regions that fired more for the same image than for a similar new one, but there were a few differences between those who did well on the memory test and those who didn't. People who were adept at recalling which smiling portrait of Clinton was the one they'd already viewed had more neurons that were devoted to that picture. And their neurons were more finicky; their portrait-specific neurons in the hippocampus (a part of the brain necessary for memory) fired much less when a similar, but not identical, image showed up.

So, if we have neurons that perk up for a particular image of Bill Clinton, what does that say about the Jennifer Aniston cells, which fire for different images of the actress and also for pictures of her Friends co-star Lisa Kudrow?

One possibility is that some cells are in charge of responding to concepts (Jennifer Aniston, people who acted in Friends, etc.) while others handle the task of discriminating among pictures of Aniston. Another possibility is that the same cells play a role in both processes, and the likelihood that these neurons will be highly discerning depends on the task at hand.

It's possible that the low performers didn't have very selective neurons because their epilepsy had caused impairments in the hippocampus. But the neuron activity in the low performers' hippocampi was not generally different from that of people who did well on the test. They also didn't have any differences in amounts of neurons outside the hippocampus that fire for a particular image.

This indicates that the ability of neurons in the hippocampus to be selective in their firing helps us call on individual memories, concluded the researchers, who published the findings today in Proceedings of the National Academy of Sciences.

https://braindecoder.com/post/people-wi ... 1279960737


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