The European Journal of Neuroscience published a TMS study done by L. Fadiga, L. Craighero, G. Buccino, and G. Rizzolatti, which investigated the neural mechanisms underlying speech perception. Through TMS, they demonstrated that while listening to speech, there is an increase of motor-evoked potentials recorded from the listeners’ tongue muscles when the words involve tongue movements upon pronunciation. The excitement of the listener’s motor cortex and thus tongue muscles was revealed by TMS. They also found stronger effects for words than for pseudo-words, meaning there is some motor result of recognizing an existing word (or at least one they are aware of). The activation is very specific because phonemes requiring a stronger use of the tongue muscles automatically excite motor centers controlling tongue muscles.
This is such an interesting phenomenon and seems like it could be linked to or part of the mirror neuron system. Evolutionarily, I’m not sure why this would be an important mechanism because I don’t see why it is advantageous to imitate the words of others, but perhaps on a simpler level, it helps with learning, identifying and speaking the same language. But I do think such findings will contribute to understanding speech problems and the way we perceive words and languages.
This is really interesting, and I agree that it may have something to do with the mirron neuron system. Just the other day, I was speaking with someone and noticed that she was moving her mouth along with my speech. Although in most people, these movements are less visually obvious, this study made it clear that we all do the same thing when other people speak. Maybe by physically relating the self to the other, we can better understand other people.
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