The mechanisms, through which our brain turns simple perceptions and acts into complex mental representations and ideas, are still unknown. One important question therefore is whether such complex human activities as language understanding are directly based on simple biological mechanisms controlling movements and perceptions. In an MRC-supported research, a group of scientists led by Dr Yury Shtyrov have investigated how the brain processes different words. They used magnetoencephalogprahy which registers tiny magnetic fields produced by brain cells as they process information. They found that, even when people are not listening to speech, hearing words (verbs and nouns) related to movements instantaneously activates not only brain areas responsible for sound processing, but also those that control body muscles. For example, hearing the word ‘toss’ automatically lights up hand-control areas in the brain even when no actual action is done. What’s more, they have showed that words compete in the brain and supress each other – when one word instantly activates its representation, it simultaneously reduces activity in neighbouring representations. Such a suppression is a well-known mechanism that helps control and fine-tune muscle movements and perceptions in an animal brain. The instantaneous character of these activations and deactivations in the brain’s so-called “motor system” in response to language, their automatic emergence in the absence of attention and their presence for different types of words suggest that even such a high-level human activity as language comprehension relies on basic biological mechanisms of movement and perception that we share with our animal ancestors.
The article describing this research has just been published in Proceedings of the National Academy of Sciences of the United States of America (PNAS). The link is here.