The part of the brain responsible for speech has been found and it’s enabling several other discoveries and innovations.
Researchers at Duke University and MIT have just discovered the part of the brain responsible for processing speech – the superior temporal sulcus (STS).
Truth be told, the superior temporal sulcus had been suspected for being responsible for recognition speech rhythm and timing for a considerably long time, but it’s only now that scientists are able to claim it with 100 percent certainty.
The study could prove itself valuable both in helping scientists understand how human speech is unique from all the other ones belonging to various species on the planet, and in helping scientists understand how certain speech-impairing conditions arise.
It could also help engineers and professors design innovative, next-generation computer courses that make foreign languages much easier to learn.
David Poeppel, a professor in the department of Psychology and Center for Neural Science, was very excited about the finding, informing that “We now know there is at least one part of the brain that specializes in the processing of speech and doesn’t have a role in handling other sounds”.
The auditory system, like most other sensory systems and brain patterns, is quite fond of shortcuts that it uses to protect itself from an overwhelming amount of information that would otherwise cause it to have a meltdown. One such shortcut is the brain’s ability to sample information in chunks that are similar in length to that of an average consonant or syllable.
For their study, professor Poeppel and his colleagues scanned the brains of volunteers using an MRI machine. They then played a number of sounds, varying from barking dogs to fireworks exploding to ping pong balls bouncing off he table, however the only important ones were the bits of foreign language (German) that they exposed participants to. Each of the sounds lasted between 30 and 960 milliseconds.
All other sounds except speech elicited the exact same response in the auditory cortex of the temporal lobe. The sound of speech however, was registered in the superior temporal sulcus. Speech sounds had between 480 and 960 millisecond and were the longest that the researchers played.
Tobias Overath, an assistant research professor of psychology and neuroscience at Duke, revealed that scientists went to great lengths in order to be certain that the effect they were seeing in superior temporal sulcus was infect due to speech-specific processing, and not due to some other explanation, “for example, pitch in the sound or it being a natural sound as opposed to some computer-generated sound”.
The superior temporal sulcus proved to be uniquely fine-tuned to speech patterns and rhythms, and designed to recognize them. When participants were exposed to a series of artificial sounds designed to mimic speech, the STS did not respond the way it did to natural sounds. One of the artificial sounds shared the speech’s natural frequency but lacked its rhythm, and another kept the rhythm but lacked pitch variances.
The study was publisher earlier this week, on May 18, in the journal Nature Neuroscience.
Image Source: psychcentral.com