A fascinating new finding has emerged concerning how the human brain perceived speech sounds. Particularly, the use of ultra-high resolution electrode arrays implanted on the surface of the brain has provided proof that there are discrete regions in one of the language centers performing tasks specific to speech processing.
published in PLOS Biology, the research described the use of more than 1000 sensor containing microelectrode arrays for recording brain activity at a resolution which has never been attained before. They were used for a short time on the superior temporal gyrus of patients undergoing surgery, a lobe that plays a vital role in understanding language.
While the participants were presented with syllables or control sounds that were noise with vocoding, the researchers assessed the subjects’ electroencephalography and found several distinctive patterns of the neural activities. Rather unexpectedly, that action was organized in circular blocks that measured approximately 1.7 mm in length across its width. Different blocks displayed a biased response to speech or noise sounds and also displayed differential latency of neuronal activity.
“We detected a clear demarcation of successive modules with respect to one another, and often the immediately adjacent zones had deeply different reaction properties.”
Looks like simply providing support for the speech columns. “Each of this modules addresses a subproblem in the processing of speech sounds,” says the senior author Dr. Eric Halgren. “Their levels of integration and perception revolve around the blending of the outputs gathered from these functional components.”
This modular decomposition could prove useful for understanding language deficits and devising treatment methodologies for the same. This is also likely to aid in the designing of new brain machines which would allow phonetical communication in those whose artifacts have made them speechless. The scope of application is quite broad.
However, this technique opens some very attractive new areas of research into what is perhaps one of man’s primary abilities: the use of language. We are moving closer to answering the baffling riddle of how humans manage to speak.
