Research into how bats’ brains filter noise show that they are super good at sifting through a sea of sound, and focusing on their own chirp echoes.
“With so many stimuli in the world, the brain needs a filter to determine what’s important,” said Melville J. Wohlgemuth, the lead author and a postdoctoral fellow in the Krieger School of Arts and Sciences’ Department of Psychological and Brain Sciences. “The bat brain has developed special sensitivities that allow it to pick out sounds from the environment that are pertinent to the animal. We were able to uncover these sensitivities because we used the perfect stimulus — the bat’s own vocalizations.”
The researchers experimented with five big brown bats, playing them a variety of sounds while monitoring their midbrain activity. They played recordings of natural chirps, the actual sounds bats made as they hunted. They also played artificial white noise and sounds between the two extremes. All of the sounds were identical in amplitude, duration and bandwidth.
Although sensorimotor neurons in the bat midbrain reacted to all of the sounds, the neurons involved in stimulus selection, those that guide orienting behaviors, responded selectively to a subset of the natural chirps.
Read the full report at John Hopkins University.