Attenuation of auditory Tb and N200 in response to self-modulated tones during continuous actions reflects the prediction of action consequences

Event-related potentials (ERPs) in response to tones modulated by one's own continuous actions (i.e., turning a steering wheel) are attenuated compared to those in response to tones presented externally. We investigated whether the ERP attenuation by continuous actions reflects a prediction of action consequences or a decrease in attentional resources available for auditory processing during the performance of actions. To compare these hypotheses, ERPs were measured in two conditions. In the modulation condition, participants modulated the pitch of tones by turning a steering wheel (i.e., frequent regular tones), and tones with an inconsistent pitch were occasionally presented among the regular tones (i.e., infrequent irregular tones). In the listening condition, participants listened to the same tones as in the modulation condition without performing any action. We expected that the irregular tones would elicit N2 and P3 (i.e., prediction errors) and their amplitudes should increase in the modulation than listening conditions, if more precise prediction was generated based on continuous actions; in contrast, they should decrease in the modulation than listening conditions, if attentional resources available for auditory processing decreased during continuous actions. The results showed that the amplitudes of Tb and N200 to regular tones decreased in the modulation than listening conditions, replicating the previous finding. Importantly, the amplitudes of N2 and P3 to irregular tones increased in the modulation than listening conditions. These results indicate that more precise prediction of action consequences underlies the ERP attenuation during continuous actions, which may contribute to efficient action adjustments in everyday life.