Studies on Bats to Help Treat Human Speech Disorders

by Medindia Content Team on Oct 20 2007 2:19 PM

Researchers at Texas A&M University are working on understanding how bats communicate at night, which they believe can help treat human speech disorders.

The brains of all mammals are organized in basically the same way. As such, a bat brain has many of the same structures as a human brain, which scientists say, makes it easier to infer things about human speech by studying bat communication.

Bats are the most vocal mammals other than humans.

Bat songs are similar to bird songs, but while scientists have been able to understand the link between bird songs and the bird-brain for years; it has not been the same with bats.

“The architecture of a bird brain is very different from that of a mammal brain, so it has been difficult to apply knowledge about bird communication to human speech,” said lead researcher Michael Smotherman.

He said their first goal now is to locate the part of the bat brain responsible for singing.

“The bat brain has to have some higher vocal centre that’s responsible for organizing these (vocal) sequences and patterns, and we just don’t know where it is yet. So we’re using molecular techniques to identify which regions of the brain are most active during singing,” said Smotherman.

“If we can identify those areas in a bat’s brain (responsible for communication), we can learn more about how a normal [human] brain generates and orchestrates complex communication sequences. By understanding how that works, we can then come up with testable hypotheses about what might be going on in speech disorders,” he said.

Presently, the scientists in Smotherman’s lab are studying two aspects of bat communication.

In behavioural studies, they are examining sex differences and seasonal variations in communication, and in physiology studies they are trying to try to locate the parts of the bat brain active during communication.

As of now, the team has successfully identified between 15 and 20 syllables Mexican Freetail birds use to create calls.

“No other mammals besides humans are able to use such complex vocal sequences to communicate,” said Smotherman.

The scientists have found that every male bat has its own unique courtship song.

Though the pattern of all courtship songs is similar, but each male bat uses a different syllable in its distinctive song.

During the course of their study, the researchers further found that bats also use sophisticated vocal communication to draw territorial borders, define social status, repel intruders, instruct offspring and recognize each other.