Time-frequency auditory processing in bat sonar – James Simmons (Brown University)
I’m interested in understanding how the bat’s sonar works and how?the bat’s brain makes sonar images. They make sounds, listen to echoes, and then see objects. To study echolocation, we go into the field and videotape bats using sonar for different purposes. These observations tell us in what situations bats use their sonar, and what sorts of sounds they use. If we know where the objects are in the videos, we can figure out what sounds get back to the bats. We then use a computer to generate these sounds and play them to the bats while we record responses from their brains. We want to know what the neurons in the bat’s auditory system do to process the echoes to allow the brain to see. ?We also train bats in the lab to respond to computer-generated echoes, so we can tell something about the images the bat perceives. We are developing a computer model of how the bat’s brain processes the echoes to see if the model produces the same kind of images the bat perceives. This model is part of a project to design new high-performance sonar for the U.S. Navy.