Temporal structure processing reflected by mismatch negativity

Abstract

Temporal information comprises significant aspects of complex sounds and is hierarchically organized. Using music, we examined higher-level temporal structure processing. While the note-to-note intervals are variable, the underlying isochronous beats can be realized reliably. Temporal structure processing (i.e., meter) involves further grouping of the beats. Yet, the effects of tempo (beats/min) and meter type have not been examined systematically. In this experiment, electrophysiological methods were adopted to examine how duple and triple meters are processed in different tempos pre-attentively. Using an oddball paradigm, temporal structure (Duple versus Triple), established through alternating strong and weak tones, was violated occasionally (16%). The tempo varied across conditions (Easy versus Hard). The neural sensitivity to this violation is quantified by the magnitude of mismatch negativity (MMN), using EEG. Repeated ANOVA 2 (tempo: Easy versus Hard) x 2 (structure: Duple versus Triple) examined the effects on data from 17 adults (7 males, mean age = 27.07) and results showed that the MMN was significantly larger in Duple than Triple in the Easy condition, while equal between meters in the Hard condition. The results suggest that in an easier tempo, duple structure is better tracked than triple. However, this duple-meter advantage is overridden in difficult tempos.