Mismatch negativity (MMN) is an event-related brain potential that appears when an auditory regularity is violated. Two main hypotheses have been proposed to explain it: the adaptation hypothesis and the memory-based hypothesis. Critically, they differ in whether the MMN can be distinguished from the N1. In this study, we assessed the differential contribution of the N1 and the MMN using independent component analysis (ICA) combined with model-based clustering. Our results show that the neural responses associated with the standard and deviant tones are explained by three clusters of reliable ICs with frontocentral scalp distribution. Two of these clusters exhibited a common N1 for both the standard and deviant tones and one cluster showed an enhancement of the anterior N1 at the MMN time range. These results support the adaptation hypothesis, which proposes that MMN is generated by neural mechanisms similar to those associated with auditory N1.