Neurons in Bat Brains Enable Safe Flight

You would think that flying around in the dark would mean a lot of bumps and bruises - but not for bats. As nocturnal animals, bats have special neurons in their brains that enable safe flight, according to a new study.

In order to fly around essentially blind, bats use echolocation sounds that bounce off nearby objects - such as obstacles or prey - and reflect back to them to indicate distance. In their brains, they have a spatial map representing different echo delays.

When a bat flies too close to an object, the number of activated neurons in its brain increases. As a result, the object appears disproportionately larger on the bat's brain map than objects at a safe distance, as if it were magnified.

"The map is similar to the navigation systems used in cars in that it shows bats the terrain in which they are moving," study director Dr. Uwe Firzlaff at the TUM Chair of Zoology said in a statement.

"The major difference, however, is that the bats' inbuilt system warns them of an impending collision by enhancing neuronal signals for objects that are in close proximity."

Echolocation is used by several kinds of animals besides bats, such as shrews, birds and dolphins. While all these species possess this bio sonar, bats are especially adept at flying maneuvers because they can determine lateral distance to objects as well, allowing them to not only determine where an object is in space, but where they are relative to that object.

"Bats evaluate their own motion and map it against the lateral distance to objects," explained Firzlaff.

Nerve cells in that bats' brains are what enables them to fly with such precision. These cells interpret the bats' rapid responses to external stimuli by enlarging the active area in the brain to display important information.

So not only can these skillful fliers process echo reflection time, but they can also determine the reflection angle of echoes, compare the sound volume of their calls with those of the reflected sound waves, and measure the wave spectrum of the echo.

The findings were published in the journal Nature Communications.