Brief content From ScienceNews   BY  AMBER DANCE 12:30PM, SEPTEMBER 20, 2017

Neuroscientist Nachum Ulanovsky and his colleagues of the Weizmann Institute of Science in Rehovot, Israel, studying several different species of bats, are investigating how the flying mammals perceive their environment and navigate through it. Ulanovsky asks how the firing patterns of neurons match up with the free-flying bats’ actions. In a handful of papers published since 2007, he and colleagues have identified key types of navigational neurons that scientists had also seen in rats, like place cells that fire when a bat is in a particular spot. Another type of cell, called grid cells, seems to work via an imaginary mental grid the brain lays over the real environment(SN Online: 8/5/13). These cells activate when a bat crosses the grid lines. Other neurons turn on when a bat’s head is at a particular angle. “We found them all in bats, just like in rodents,” Ulanovsky says. Those findings, though satisfying, told only half the story, he says: how a bat understands where it is at any given time. But what if the bat has a goal destination in mind, too? “We had an understanding of how point A is represented, but not point B,” he says. “It has been a big missing link.”

As an Egyptian fruit bat flew around a lab (represented by the box), place cells in its brain fired. Each colored shape represents a different location within the room where specific place cells fired.

 M.M. YARTSEV AND N. ULANOVSKY/SCIENCE 2013

In experiments reported in January in Science, Ulanovsky’s team identified hippocampal neurons responsible for keeping track of target destinations in Egyptian fruit bats (Rousettus aegyptiacus), pointy-eared critters with doglike faces that use echolocation to find tasty fruits and nectar.

Taken together, these studies are beginning to paint a picture of what goes on in the brain as a bat perceives and moves through its environment. But there’s still plenty of uncertainty about the bat brain and how well it matches to what the human brain does. “These are still big questions: How do we make sounds and how does our brain control what we make? How do we develop the sense of localization?” says Razak. “The bats continue to offer some interesting insight.”

What’s already certain is that the flying creatures have earned the respect of the scientists working with them. After all, Moss notes, the big brown bat’s brain is the size of a lima bean, but still manages to process sounds in a way human sonar engineers envy.

Further reading on Bat brain signals illuminate navigation in the dark.