Differentiating ERAN and MMN: An ERP study

In the present study, the early right-anterior negativity (ERAN) elicited b y harmonically inappropriate chords during listening to music was compared to the frequency mismatch negativity (MMN) and the abstract-feature MMN. Re sults revealed that the amplitude of the ERAN, in contrast to the MMN, is s pecifically dependent on the degree of harmonic appropriateness. Thus, the ERAN is correlated with the cognitive processing of complex rule-based info rmation, i.e. with the application of music-syntactic rules. Moreover, resu lts showed that the ERAN, compared to the abstract-feature MMN, had both a longer latency, and a larger amplitude. The combined findings indicate that ERAN and MMN reflect different mechanisms of pre-attentive irregularity de tection, and that, although both components have several features in common , the ERAN does not easily fit into the classical MMN framework. The presen t ERPs thus provide evidence for a differentiation of cognitive processes u nderlying the fast and pre-attentive processing of auditory information. Ne uroReport 12:1385-1389 (C) 2001 Lippincott Williams & Wilkins.