Bats use the same neurons for social navigation as they do for spatial navigation. The study involved wireless neural recording and imaging of groups of Egyptian fruit bats flying in a large room. The bat’s “place” neurons in the hippocampus fired not only to indicate the animal’s location but also the identity of other bats present. This finding could shed light on the role of the hippocampus in social and spatial aspects of memory loss in diseases like Alzheimer’s.
Many mammals — including bats and humans — are believed to navigate with the help of a brain structure called the hippocampus, which encodes a mental “map” of familiar surroundings. For example, as you walk around your neighborhood or commute to work, individual “place” neurons in the hippocampus fire to indicate where you are. In the new study, researchers at the University of California, Berkeley, used wireless neural recording and imaging devices to “listen in” on the hippocampal brain activity of groups of Egyptian fruit bats as they flew freely within a large flight room — often moving among tightly clustered social groups — while tracking technology recorded the bats’ movements.
The researchers were surprised to find that, in this social setting, the bat’s place neurons encoded far more information than simply the animal’s location. As a bat flew toward a landing spot, the firing of place neurons also contained information about the presence or absence of another bat at that spot. And when another bat was present, the activity of these neurons indicated the identity of the bat they were flying toward. “And surprisingly, we found it in the hub of what was supposed to be the brain’s GPS. We found that it still acts as a GPS, but one that is also tuned to the social dynamic in the environment.”
