Neuroscientists at Brown University and from the Republic of Georgia have learned how bats can remain on a target despite obstacles in their midst.
The key lies in bats’ neural response to echoes from their sonar pulses. Bats can separate the cavalcade of echoes returning from their sonar pulses by distinguishing changes in amplitude — the intensity of the sound — between different parts of each echo within 1.5 decibels, to decide whether the object is a target or just background clutter.
The minute change in amplitude is enough to cause a delay in the bats’ neural response to an echo, letting the bat know what is clutter and what is the target. It is as if the bat is using two screens — a main screen that keeps it locked in on its target by virtue of its neural response to the echo and another, secondary screen that keeps note of surrounding objects, but doesn’t fixate on them.
"Everything the bat sees using sonar is based on the timing of the neural responses and nothing else,” said James Simmons, professor of neuroscience at Brown and an author of the study.
"What the bat does is it takes clutter and defocuses it, like a camera would, so the target remains highly defined and in focus,” he added.
The study was published this week in Science.
Keywords: sonar pulses