Introducing the brain: how place cells work (Introduction)

by David Turell , Monday, July 12, 2021, 19:01 (1013 days ago) @ David Turell

A special area of the hippocampus used as we travel:

https://www.sciencedaily.com/releases/2021/07/210708143856.htm

"When driving up to a busy intersection, you probably pay more attention to where you will be in the near future than where you are at that moment. After all, knowing when you will arrive at the intersection -- and whether you need to stop or slow down to avoid a collision with a passing car, pedestrian or cyclist -- is usually much more important than knowing your current location.

"This ability to focus on where we will be in the near future -- rather than where we are in the present -- may be a key characteristic of the mammalian brain's built-in navigation system, suggests a new study appearing online Thursday, July 8, in the journal Science.

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"When the researchers compared the bats' flight paths with their neural readings, they found that the activities of the bats' "place cells" -- special type of neurons responsible for encoding an animal's spatial position -- were often more closely correlated with where the bats would be in the near future, rather than where they were in the moment.

"'We wanted to find out: Does the neural activity at the present moment do a better job at representing a past or future position than it does the actual present position? And we found that, for some neurons, the neural activity actually does a much better job of representing a future position," said lead author Nicholas Dotson, who conducted the research as a postdoctoral scholar at UC Berkeley. "The finding shows that neural activity in this region is representing more than the bat's present position -- it's tentatively representing a full flight trajectory."

"Place cells, located in a region of the brain called the hippocampus, work together to form an innate "GPS system" for a variety of land animals, including humans. As an animal explores a new environment, different place cells activate at different positions, creating an internal map of the territory that can be saved and stored.

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"When Yartsev and Dotson compared the timing of neural activity with the bats' flight paths, they found that when shifting the bats' positions forward in time -- by comparing the neural activity with the locations where the bats would be in a few hundred milliseconds, or in a second -- suddenly, the neural activity correlated much more strongly with spatial position.

"'Based on the data, you might assume that some neurons don't encode spatial information at all, because there is no correlation with the position at time zero or the present moment," Yartsev said. "But if you compare their activity to a position a second in the future, suddenly the correlation is incredibly sharp.'"

"The findings suggest that place cells' activity doesn't just represent a single current position, but actually a trajectory that stretches into the near future, and into the past, as well."

Comment: The researches, based on logic, assume we use place cells as bats do. This brain ability must be designed into hippocampal organization. It is not clear how chance mutation could create this necessary system in a stepwise fashion..