Oscillatory brain networks in continuous speaking and listening

Speech production and perception are fundamental processes of human cognition that both rely on an internal forward model that is still poorly understood. Here, we study this forward model by using Magnetoencephalography (MEG) to comprehensively map connectivity of regional brain activity within the brain and to the speech envelope during continuous speaking and listening. Our results reveal a partly shared neural substrate for both processes but also a dissociation in space, delay and frequency. Neural activity in motor and frontal areas is coupled to succeeding speech in delta band (1-3 Hz), whereas coupling in the theta range follows speech in temporal areas during speaking. Neural connectivity results showed a separation of bottom-up and top-down signalling in distinct frequency bands during speaking. Here, we show that frequency-specific connectivity channels for bottom-up and top-down signalling support continuous speaking and listening in a way that is consistent with the predictive coding framework.