‘Bat nav’ system controls orientation during flight

A detailed understanding of how the neural navigation system of a bat brain acts in three dimensions sheds light on how mammals orient themselves in complex environments. This system acts as an internal compass that gives animals a continuous sense of direction and location as they move around.

HFSP Program Grant holder Nachum Ulanovsky and colleagues
authored on Tue, 02 December 2014

Many mammals need to navigate complex, three-dimensional (3D) environments, whether they are monkeys swinging from the trees or humans finding their way through multi-storey buildings, but little is known about how this information is processed by the brain. HFSP Program grantee Nachum Ulanovsky from the Weizmann Institute of Science, together with graduate student Arseny Finkelstein and colleagues, gains new insights into how the sense of direction is maintained by recording neural activity in the brains of bats as they fly or crawl. This study was conducted as part of an HFSP project that aimed to elucidate the representation of 3D space in the bat brain. They found that certain cells respond to the bats’ horizontal and vertical orientation, and these so-called head-direction cells track direction in three dimensions as the bats manoeuvre. These cells create a 3D neural compass that is represented in 3D toroidal coordinates, which gives a precise orientation and even enables the bat to know if it is upside down or upright.

Figure: An Egyptian fruit bat. The presubiculum of these bats contains head-direction neurons that form ‘3D neural compasses’, which represent spatial orientation in toroidal coordinates. First published in Nature (2014): Three-dimensional head-direction coding in the bat brain. Finkelstein et al. 10.1038/nature14031.  Photograph by Haim Ziv.

“Thus, as the animal rotates in the horizontal plane, neural activity moves gradually around the ring, maintaining a stable representation of direction,” David Rowland and May-Britt Moser explain in an accompanying News & Views article in Nature. Rowland and Moser conclude that looking at the compasses of multiple mammalian species may offer insights into the basic principles of the navigational system. Although this study was conducted in bats, the authors believe that their findings should also apply to non-flying mammals, including mice – that spend much of their time upside-down, similar to bats – and humans, in which dysfunction of the 3D compass may cause 3D disorientation, such as vertigo.

Reference

Three-dimensional head-direction coding in the bat brain. Arseny Finkelstein, Dori Derdikman, Alon Rubin, Jakob N. Foerster, Liora Las, and Nachum Ulanovsky.Nature (2014) DOI: 10.1038/nature14031. 

Other References

Neuroscience: A three-dimensional neural compass. David C. Rowland, May-Britt Moser. Nature (2014) doi:10.1038/nature14076.

Link to article