Multitasking Bats Crucial to Understanding Human Impairments
February 27, 2012 – Studying how bats multitask may one day help scientists understand dyslexia and hearing, language and speech impairments in humans.
In a study recently published in the European Journal of Neuroscience, Jagmeet Kanwal, associate professor of neurology at Georgetown University Medical Center (GUMC), has for the first time revealed how bats divide duties at the single neuron level.
Kanwal shows that neural circuits within the two brain halves allow a bat to navigate or “see” its surroundings through echolocation and carry on a “conversation” at the same time.
This means they can make warning sounds that means “watch out!” while using complicated echolocation.
Bats are not blind, but they don’t see well. Echolocation, which bats and other animals use, involves making sounds and listening to the echoes as they bounce off nearby objects. This is how they identify and locate the things around them.
But the division of labor in bats’ brains isn’t equal, Kanwal says, leading to what he describes as a “lopsided brain.”
Kanwal found that neurons in the right cerebral cortex responded more strongly to echolocation than to communication sounds or “calls,” while the left side neurons were only more sensitive to changes in the loudness of a call.
“It appears that the cerebral cortex halves are wired differently, allowing one side, usually the left, to more effectively process speech or speech-like communication sounds than the other,” Kanwal says. “The right half processes small changes in the pitch of the navigation signals akin to the pitch contour in a melody."
Kanwal says understanding the neurologic basis of speech and music processing is critical for alleviating communication deficits in children (dyslexia and language impairments), and repairing damage (aphasias) to speech areas after a stroke.
“Being able to examine the nature of lopsidedness at the level of single neurons in a non-human mammal opens the door to an in-depth understanding of this phenomenon,” the scientist explains.
Kanwal is the author of Bats Sing, Mice Giggle: The Surprising Science of Animals’ Inner Lives, first published in 2010 with co-author Karen Shanor.