Word-selective EEG/MEG responses in the English language obtained with fast periodic visual stimulation (FPVS)

Fast periodic visual stimulation (FPVS) allows the objective measurement of brain responses of human word discrimination (i.e., reproducible word-category-selective responses) with a high signal-to-noise ratio. This approach has been successfully employed over the last decade in a number of scalp electroencephalography (EEG) studies. Three important advances for research on word-selective brain responses were achieved in the present study: (1) we extend previous evidence of robust word-category-selective responses to the English language, (2) report results for combined EEG and MEG signals, and (3) source estimation results. English words were presented periodically (2 Hz) among different types of letter strings (10 Hz; consonant strings, non-words, pseudo-words) while recording simultaneous EEG and MEG in 25 participants who performed a simple non-linguistic colour detection task. Data were analysed in sensor and in source space. With only 4 minutes of stimulation, we observed a robust word discrimination response in each condition, even when words were embedded in sequences of word-like pseudo-words. This response was larger in non-words and largest in consonant strings. We observed left-lateralised responses in all conditions in the majority of our participants. Cluster-based permutation tests revealed that these responses were left-lateralised in sensor as well as in source space, with peaks in left posterior regions. Our results demonstrate that the FPVS approach can elicit robust English word discrimination responses in EEG and MEG within only a few minutes of recording time. Together with source estimation, this can provide novel insights into the neural basis of visual word recognition in healthy and clinical populations.