Bat brain offers clues into human hearing

WASHINGTON - How can a mother, in the middle of a noisy party, suddenly hear a child’s cry, even when it’s not her own baby? A scientist is studying bat brains to solve the puzzle.

Bridget Queenan, doctoral candidate in neuroscience at Georgetown University Medical Centre in San Diego, US says neurons (brain cells) in bat brains seem to “shush” other neurons when relevant sounds come in - a process she suggests may be present in humans as well.

She has also found that “some neurons seemed to know when to yell louder to report communication sounds over the presence of background noise.”

“We can now start to piece together how the cells in your brain are able to deal with the complex sensory environment we live in,” Queenan says, according to a university statement.

Bats are especially interesting subjects because they process sound through echolocation, a kind of biological sonar.

The findings are scheduled for presentation at the annual meeting of the Society for Neuroscience in San Diego.

Bats use the echoes of their emitted sounds to navigate and hunt.

“What we are trying to figure out is how can a bat fly around echolocating - screeching and listening to its own individual sounds bouncing back - amidst a whole colony of hundreds of other echolocating bats - and possibly hear another bat saying ‘watch out’!

“Bats actually do make these cautious calls quite a bit,” she says. “In fact, bats have a whole host of communication sounds - angry sounds, warning sounds, and sounds that says ‘please don’t hurt me’.”

The auditory processing area in bats’ brains is larger than other centres. Humans, in comparison, have a larger visual processing centre as they operate predominantly by sight.