Expectations and Motor Signals Shape Auditory Evoked Responses in an Independent Manner

Voluntary actions are usually accompanied by sensory consequences that evoke neural responses in relevant sensory regions. These evoked responses are different when compared to those evoked by otherwise identical physical stimulation not associated with preceding actions (sensory attenuation). A common model suggests that sensory attenuations are caused by efference signals associated with the binding of actions with sensory outcomes. Nevertheless, the information encoded in such signals is debated, with some theories suggesting they convey predictive information while others suggest they convey global motor information regardless of specific outcome expectations. To address this debate, we recorded EEG data while participants (n=30) learned to associate motor or visual cues with corresponding tones. Following 8 repetitions of cue-tone learning, participants successfully learnt the association (>84% correct). At the neural level, the amplitude of auditory evoked responses (N100) decreased across repetitions, as the binding between cues and tones strengthened. In addition, N100 amplitude was attenuated when preceded by motor vs, visual cues. Most importantly, we did not find an interaction effect between repetition and cue type, suggesting a similar sensory attenuation effect across repetitions. Specifically, we show significant sensory attenuation even at the first repetition, when no expectation could be formed. Thus, our results suggest that the sensory attenuation effect does not change while forming experience with action-outcome contingency. These results have implications for contemporary models of sensorimotor control and predictive mechanisms.