Bats use brain just like humans

Upsetting the notion that only humans use different sides of their brains to distinguish different aspects of sound, a team of US researchers has found that bats, too, use both sides of their brain to listen.

Researchers from the Georgetown University Medical Center and American University found that, like humans, mustached bats use the left and right sides of their brains to process different aspects of sounds.

Till date, aside from humans, no other animal, not even monkeys or apes, have been seen to use such brain specialisation for sound processing -- meaning that the left brain is better at processing fast sounds, and the right processing slow ones.

"The findings open a pathway to study bat brains in order to understand certain human language disorders and potentially even improving computer speech recognition," said the study's senior author and neuroscientist Stuart Washington.

The findings of asymmetrical sound processing in both human and bat brains make evolutionary sense.

"The slower timing of the right hemisphere may allow us to identify who is speaking to gauge their emotional state via tone-of-voice and to tease out pitch in music that can ultimately lead to the formation of cultures," Washington added.

It is, therefore, reasonable to understand why humans needed to evolve this asymmetry in their brains.

For mustached bats, the need is even more compelling.

Bats need to use the fast timing of the left hemisphere to distinguish communication sounds from each other, because their communication sounds have rapid changes in frequency.

Otherwise, they cannot communicate with other bats, and bats are even more social than humans.

"The bats also need to use the slow timing of the right hemisphere to use sonar - which relies on detecting small changes in frequency - to track the velocity of the fast-moving insects they fly after and eat," Washington added.

This asymmetric sampling in bats is sex-dependent.

Males have more asymmetry than females, that is also consistent with humans.

Women tend to use both the left and right hemispheres for language but men largely use just the left hemisphere.

The study was published in the journal Frontiers of Neuroscience.