Frontocingulate-parietal-limbic circuits associated with both ruminative brooding and self-regulatory processes.

Introduction: Ruminative brooding is a transdiagnostic symptom defined as repetitive dwelling on thoughts and emotions, and is linked to emotion dysregulation, maladaptive metacognitive beliefs, and abnormal interoception. The relative contributions of these factors and their neural mechanisms remain unclear. In this exploratory study, we mapped these processes onto directed cross-frequency coupling (CFC) networks using resting-state electroencephalography. Methods: We first identified symptoms of interest for CFC analyses by employing regularized symptom networks, revealing two clusters relevant to brooding: one dominated by interoceptive/mindfulness dimensions and another by metacognitive/emotional dysregulation, with brooding belonging to the latter. We then examined links between representative symptoms from each cluster and resting-state cross-frequency phase-amplitude coupling (PAC) using partial least squares correlation (PLS-C). Results: Emotional dysregulation and brooding dimensions co-varied with delta-beta PAC (representing a "brooding/dysregulation" neural signature), whereas mindfulness symptoms co-varied with beta-gamma and theta-gamma PAC (representing a "mindfulness/interoception" neural signature). More specifically, for the brooding/dysregulation signature, prefrontal and cingulate phase activity modulated amplitudes in regions implicated in emotion regulation and interoception. In contrast, the mindfulness/interoception signature reflected coupling within circuits supporting emotion regulation/interoception. Discussion: Overall, our results indicated that brooding was more tightly linked to maladaptive metacognitive beliefs and emotional dysregulation than to mindfulness/interoception, consistent with resistance toward one's thoughts and emotions. Neurally, as reflected through multivariate PLS-C covariance patterns, this may be linked to compensatory top-down control from prefrontal and cingulate areas over interoceptive, affective, and self-referential systems, pointing to the potential value of therapies that cultivate self-acceptance and modify maladaptive metacognitive beliefs for reducing rumination.