New Findings About How The Brain Processes Words
The sound of words gets processed in a separate part of our brain from word meaning, finds Oxford research published today in the Journal of Neuroscience.
Neuroscientists in Oxford's Centre for Functional Magnetic Resonance Imaging of the Brain and Oxford's Department of Experimental Psychology found that the front part of the section of our brain known as 'Broca's area' deals with word meaning, whereas the back part of Broca's area deals with word sound.
Since the 19th century it has been clear that Broca's area is critical for language, and modern brain imaging studies suggest that the area is involved in processing both the sound and meaning of words. However, it was previously unclear whether the region acts as a single unit or if it can be subdivided into separate areas.
Researchers used a non-invasive technique called transcranial magnetic stimulation to momentarily disrupt normal brain functioning in either the front (anterior) or back (posterior) portion of Broca's area. Stimulating the front part selectively interfered with people's ability to identify synonyms(words that mean the same, for example 'dress' and 'frock'), suggesting that this area controls the processing of meaning. Stimulation of the back part interfered with people's ability to identify homophones (words that sound the same, for example 'throne' and 'thrown'), suggesting that this part deals with sound.
Transcranial magnetic stimulation (TMS) uses a rapidly changing electrical current within a conducting coil to create a magnetic field. When this small coil is placed against the scalp, its magnetic field disrupts the brain processing in that particular area. In effect, it allows scientists to temporarily switch off, or at least inhibit, specific areas of the brain.
Participants in the experiment were shown two words at once on a computer screen. They were asked first to decide whether or not the words were synonyms (such as 'biscuit