Charting the functional relevance of Broca's area for visual word recognition and picture naming in Dutch using...

Magnetoencephalography (MEG) has shown pseudohomophone priming effects at Broca's area (specifically pars opercularis of left inferior frontal gyrus and precentral gyrus; LIFGpo/PCG) within ∼100ms of viewing a word. This is consistent with Broca's area involvement in fast phonological access during visual word recognition. Here we used online transcranial magnetic stimulation (TMS) to investigate whether LIFGpo/PCG is necessary for (not just correlated with) visual word recognition by ∼100ms. Pulses were delivered to individually fMRI-defined LIFGpo/PCG in Dutch speakers 75-500ms after stimulus onset during reading and picture naming. Reading and picture naming reactions times were significantly slower following pulses at 225-300ms. Contrary to predictions, there was no disruption to reading for pulses before 225ms. This does not provide evidence in favour of a functional role for LIFGpo/PCG in reading before 225ms in this case, but does extend previous findings in picture stimuli to written Dutch words.