UC Berkeley study of bats uncovers insight into mammal brains
BERKELEY - The phrase "blind as a bat" may be an alliterative simile, but that doesn't make it true. Bats can in fact see, but they use still more of their senses to navigate. Now researchers at University of California, Berkeley have released a study about how bats navigate in social groups, and they think it may provide answers to some human behavior and even insight into Alzheimer's disease.
The study looked at bats' hippocampus, which helps all mammals make their way through the world by "mapping" familiar surroundings and storing the information. It's how we remember which way to walk home or where the grocery store keeps its deli.
Researchers at UC Berkeley used wireless neural devices to monitor the hippocampal brain activity in Egyptian fruit bats as they flew freely in a large flight room and moved among "tightly clustered" social groups of other bats. The scientists found something that surprised them, they said. The neurons in the bat brains that stored "place" also stored far more than just the bat'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," said UC Berkeley science writer Kara Manke in a statement Wednesday. "And when another bat was present, the activity of these neurons indicated the identity of the bat they were flying toward."
Michael Yartsev, associate professor of bioengineering at UC Berkeley, said that what is groundbreaking about this is that it is the one of the first papers to show identity representation in a non-primate brain.
"And surprisingly, we found it in the hub of what was supposed to be the brain's GPS," said Yartsev. "We found that it still acts like GPS, but one that is also tuned to the social dynamic in the environment."
In short, they found a neural basis in collective behavior -- shining a light on what makes social animals, including people, tick.
And like people, bats seem to have their favorites and others they'd rather not eat lunch next to.
"The bats also showed strong preferences for flying toward specific 'friend' bats," said postdoctoral fellow Angelo Forli.
So while bats in the night sky appear to be scattered, herky-jerky and, yes, perhaps blind, they are in fact acutely aware of where they are and where they are going.
"They would spend time with specific individuals and show specific and stable places where they liked to go," said Forli.
Researchers said that their findings help illuminate why damage to the hippocampus in humans has been linked to both social and spatial aspects of memory loss in neurodegenerative diseases like Alzheimer's.
