How mums can hear a baby cry even in a noisy party

Monday, November 15, 2010

WASHINGTON - Ever wondered how a mother hears the sound of a baby crying at the other end of the room in a noisy party, even if it’s not hers?

Neuroscientists have discovered the ability of the bat brains to know what sounds to focus on and which to ignore.

Bridget Queenan, a doctoral candidate in neuroscience at Georgetown University Medical Center, has found out that some neurons in the brains of bats indeed tell other neurons to ’shush’ and others to ‘yell louder’ in order for key sounds to be heard above background noise - a process that may be working in humans as well.

Not only do the brains of bats have to process a constant stream of pulses and echoes, they also have to simultaneously process the bats’ social communication, she said.

“So 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,” she added.

Bats call out and then listen to their own echoes produced when those calls bounce off nearby objects. Bats use these echoes to navigate and to hunt.

“What we are trying to figure out is how a bat can 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,” said Queenan.

“In fact, bats have a whole host of communication sounds: angry sounds, warning sounds, and sounds that says ‘please don’t hurt me,” she added.

“Humans operate predominantly by sight so a huge portion of our brain is devoted to vision processing. Bats, however, operate by sound,” said Queenan.

The researchers found that some bats’ neurons control the activity of other neurons when important sounds are perceived.

“All organisms are constantly assaulted by incoming stimuli such as sounds, light, vibrations, and so on, and our sensory systems have to triage the most relevant stimuli to help us survive,” said Queenan.

“As humans we are not only sensitive to a child’s cry, but we notice flashing ambulance lights even though we are engrossed in something else. We want to know how that happens,” she added.

Queenan said her next task was to record brain neurons in bats that are not only awake, but also flying.

The scientists presented their study at the annual meeting of the Society for Neuroscience in San Diego. (ANI)

Filed under: Science and Technology

will not be displayed