Early ERP components to gaps in white noise: onset and offset effects

The differences between waveforms to click pairs and gap offsets, compared with gap onsets, suggest that potentials to gap onsets involve more than just onset/offset responses (N1, N1a) but also the subsequent perception of the cessation of an ongoing sound (N1b). In previous studies, two processes were defined: (1) M-process to deviation from the preceding auditory pattern and (2) C-process in response to acoustic change within an ongoing stream. We propose that N1b is different from these processes because it relates to the negation of an ongoing stimulus, and we thus call it an N-process.