Scientists from the University of California, Berkeley, have worked out which regions of the brain are active when certain words are heard, allowing them to generate an ‘atlas’ of how words are represented across the brain.
By recording the brain activity of seven volunteers listening to stories in a functional Magnetic Resonance Imaging (fMRI) scanner, Alexander Huth and colleagues were able to show that words with similar meanings are represented in the same areas of the cerebral cortex, the brain’s outermost layer of tissue. For instance, the area activated by “wife” was also activated by other words relating to family, such as “husband” and “children”.
Importantly, the stories had more than 3000 different words heard in different contexts. A good example comes from “top”, which can be used to describe clothing, but can also be used in the context of mathematics. The researchers were therefore able to show that the brain activity related to the meaning of words rather than their sound, since the same word could activate different brain regions in different contexts.
Interestingly, the brain atlases were fairly similar between the seven participants, suggesting that their brains organised the meanings of words in similar ways. Alexander Huth suggested that “it is possible that this approach could be used to decode information about what words a person is hearing, reading, or possibly even thinking”, a feat which would be easier if brain atlases are similar across large populations. One possible use of this would be a language decoder that would allow patients with locked-in syndrome or motor neurone disease to communicate through a computer.