Bat Brains and Island Maps: Nature’s Built-in Compass

How do animals find their way in the world? Scientists had been stumped until the discovery of specialized neurons in the brain gave them new clues. Place cells and grid cells help animals know where they are and build mental maps, and head direction cells act like a compass, showing the animal which way it is facing. However, these discoveries have been in laboratories, using small arenas that lack the multitude of sensory inputs found in the real world. So the question remains: how does the brain’s navigation system respond when confronted with the complexity of the real world?

To answer this, neuroscientists studied head direction cells in Egyptian fruit bats. They placed electrodes in the bats’ brains then released them on a remote island near East Africa. They simultaneously recorded the activity of head direction neurons and tracked these bats using GPS, finding that the neural compass works the same in the real world as it does in the lab! The compass was stable no matter where the bats flew, or how the moon or clouds changed across the sky. But the compass was not perfect from the start, taking a few nights to stabilize and adapt to the new island environment. It seems the bats gradually learned the layout of the island, potentially using vision and other sensory cues to better ground their neural compass. 

By taking neural recordings into the wild, this study connects our understanding of the navigation centers of the brain between tightly controlled experiments and real world behaviors. Thanks to these bats, scientists are one step closer to understanding how all animals find their way in a complicated world.

This study was led by Shaked Palgi, a PhD student at the Weizmann Institute of Science.

Managing Correspondent: Sophia Renauld

Press Article: Remote Island Research Reveals Insights Into Bats’ Neuronal “Compass”, Technology Networks

Original Research Article: Head-direction cells as a neural compass in bats navigating outdoors on a remote oceanic island, Science

Image Credit: Bat Photo by James Wainscoat on Unsplash