Scientists find 3-D compass in brains of fruit bats

REHOVOT, Israel, Dec. 4 (UPI) -- Ever wonder how the brain keeps track of where exactly the body it's controlling is -- which way is up, which is down? It turns out, brains are outfitted with a 3-D compass. Or at least the brains of fruit bats are.

In a new study, researchers at Weizmann Institute of Science were able to use mobile imaging technology to monitor the neural activity of Egyptian fruit bats as their careened through the night sky.

"We're the only lab currently able to conduct wireless recordings in flying animals," lead researcher Arseny Finkelstein told BBC News. "A tiny device attached to the bats allows us to monitor the activity of single neurons while the animal is freely moving."

Implanted microelectrodes honed in on a specific sub-region of the hippocampal formation in the bats' brains, revealing that neurons there activated in correlation with the movement, direction and angle of the animal's head. The highlighted neural activity formed a sort of 3-D compass inside the brain.

Researchers say the feature is unlikely to be unique to the fruit bat; similar neural setups probably help a range of mammals, from modern man to dolphins and whales, navigate their three-dimensional worlds.

"Bats and rats are separated by millions of years of evolution. And yet, if you look at the same brain regions of these two species, you find place cells, head-direction cells, and you find grid cells," Finkelstein said. "That's why we think this might be relevant for humans too. So we think that's one of the exciting elements in neuroscience."

The study was published in the journal Nature this week.