The Dynamic EEG signature of groove: Theta oscillations respond to syncopated rhythm

Groove, the compelling and often pleasurable urge to move to music, is strongly influenced by rhythmic features like syncopation, frequently exhibiting an inverted U-shaped relationship with complexity. However, the neural dynamics underlying the emergence of groove over time are not well understood. This study aimed to investigate the temporal evolution of groove perception and its neural correlates using electroencephalography (EEG). Participants listened to synthesized drum patterns varying systematically in syncopation complexity (low, medium, high) while EEG was recorded. After each rhythm, participants rated their subjective “desire to move” and “feeling of pleasure”. We analyzed the dynamics of middle frontal theta-band (4-8 Hz) power across four repetitions of the core rhythmic phrase and correlated this activity with behavioral ratings, complemented by sLORETA source localization. Behaviorally, results robustly confirmed the inverted U-shaped function, with medium syncopation eliciting the highest groove ratings. Neurally, middle frontal theta power paralleled this pattern, showing maximal amplitude for medium syncopation, particularly during later repetitions. Importantly, theta power during the 3rd repetition positively correlated with both desire to move and pleasure. Source analysis localized these significant correlations primarily to the supplementary motor area (SMA) and anterior cingulate cortex (ACC). These findings reveal middle frontal theta oscillations originating from an SMA-ACC network as a dynamic neural signature tracking the subjective experience of groove. The results support a predictive coding framework where theta activity reflects precision-weighted prediction errors, optimally balanced by moderate rhythmic complexity, thus linking rhythmic prediction processing, motor system engagement, and affective valuation central to the groove phenomenon.