In the recently discovered sound-induced illusory £ash phenomen- on, a single £ash accompanied with two auditory beeps is perceived as two £ashes in a majority of trials. Here we asked what the neural substrates distinguishing illusion and no-illusion (i.e. perception of single £ash) percepts are under identical stimulus con¢guration. Wavelet based method was used to analyze g band (4 30 Hz) re- sponses in the event-related potential (ERP) signals recorded over visual cortical regions. We found: (i) signi¢cantly higher oscillatory and induced g band responses in illusion than in no-illusion trials