ACTION SHAPES THE NEURAL REPRESENTATION OF SOUND: ENHANCED FREQUENCY-FOLLOWING RESPONSES TO SELF-GENERATED SOUNDS

Self-generated actions produce predictable sensory consequences. Predictive coding and forward-model frameworks suggest that motor commands generate sensory predictions that suppress cortical responses to their sensory consequences. In auditory research, this suppression is commonly observed as an attenuation of the N1 event-related potential (ERP). The frequency-following response (FFR) is a sustained ERP phase-locked to periodic sounds indexing temporal coding of acoustic fine-structure and envelope. The FFR captures earlier stages of auditory processing than cortical components such as N1. Despite extensive literature on sensory attenuation in cortical ERPs, no study has tested whether sound self-generation modulates the FFR. To address this gap, we recorded EEG in 10 young healthy participants using an adapted auditory self-generation paradigm suited to elicit FFRs. We contrasted three conditions: Motor-Auditory, Auditory, and Motor-only. In the Motor-Auditory condition, participants generated trains of a repeated syllable (/da/) by pressing a force-sensitive button; natural variations in pressing force controlled syllable loudness, increasing the sense of agency over stimulus generation. In the Auditory condition, the same trains were replayed without button presses. The Motor-only condition controlled motor-related responses, using equivalent press/release patterns without sound. As FFRs reflect neural synchronization to sound periodicity, we hypothesized that self-generation would enhance FFR amplitude and spectral power. Consistent with literature, N1 responses to the first stimulus of each train were attenuated for self-generated versus passively heard sounds. Crucially, FFRs showed increased amplitude and spectral power in the same contrast. These preliminary results suggest that self-generation effects extend to early, subcortico-cortical stages of auditory processing.