No evidence for peripheral mechanism attenuating auditory ERPs to self-induced tones.

The N1 and P2 event-related potentials (ERPs) are attenuated when the eliciting sounds coincide with our own actions. Although this ERP attenuation could be caused by central processes, it may also reflect a peripheral mechanism: the coactivation of the stapedius muscle with the task-relevant effector, which reduces signal transmission efficiency in the middle ear, reducing the effective intensity of concurrently presented tones, which, in turn, elicit lower amplitude auditory ERPs. Because stapedius muscle contraction attenuates frequencies below 2 kHz, no attenuation should occur at frequencies above 2 kHz. A self-induced tone paradigm was administered with 0.5, 2.0, and 8.0 kHz pure tones. Self-induced tones elicited attenuated N1 and P2 ERPs, but the magnitude of attenuation was not affected by tone frequency. This result does not support the hypothesis that ERP attenuation to self-induced tones are caused by stapedius muscle contractions.