Weekly Article: New Discoveries within “Bat-Nav”

New Discoveries within “Bat-Nav”

By: Raquel Zuniga

The brains of bats have an inherent 'compass' or “bat-nav” system, that enables them to navigate in three dimensions. This explains the long-standing mystery of how bats manage to orient themselves in the air as well as on the ground. These systems are not 'compasses' in the sense of north or south; they are systems for keeping track of information that the brain has integrated from the senses. The “bat-nav,” located in the hippocampus, is responsible for mapping a bat’s own location as well as the location of others, based on new experiments. 

Researchers in Israel experimented on bats while researchers in Japan experimented on rats, both social creatures like humans, and have discovered that their brain cells are attuned to other animals as well as themselves. (Because mammals are social creatures, they need to know the locations of others in their groups so they may interact, learn from each other, and move around together.) These unexpected discoveries deepen the understanding of the mammalian brain’s navigation system and may help explain why recalling events often involves re-envisioning a place, street, or landscape.

The experiment done on bats was conducted by neurobiologist Nachum Ulanovsky and his colleagues at the Weizmann Institute of Science in Rehovot, Israel. This experiment was designed to see what happens in a bat’s brain when it tracks the movement of another bat. The researchers trained pairs of Egyptian fruit bats, Rousettus aegyptiacus, in a room to fly from one post to another and back, in return for a treat. The scientists implanted electrodes into the bats’ hippocampuses to record their brain signals. Based off observations, the same part of the brain seems to track both the physical landscape and the social landscape, says Ulanovsky—but using slightly different cell populations.

The experiment done on rats was conducted by Shigeyoshi Fujisawa at the RIKEN Brain Science Institute in Saitama, Japan. This experiment made similar conclusions. As with previously identified parts of the navigation system, it's probable the phenomena extend to other mammals including humans, researchers say. Whether social place cells are exclusively for tracking other members of the same species, or whether they are part of a system of hippocampal cells that encode all sorts of trajectories- be they those of animals or objects- isn’t yet clear.

Read more at: https://www.nature.com/articles/d41586-018-00484-w

And read the published experiments at: http://science.sciencemag.org/content/359/6372/213 and http://science.sciencemag.org/content/359/6372/218.long