An investigation of the interaction of trait repetitive negative thinking and neuroticism on brain activity during negative self-referential processing: a cross-sectional fMRI study.

Repetitive negative thinking (RNT) and neuroticism are two of the most prominent transdiagnostic risk factors for internalizing disorders. Previous research highlighted a complex relationship between neuroticism and RNT. However, no study has yet examined their interaction at the neural level. Trait RNT and neuroticism were assessed in a sample of 126 healthy participants, followed by a fMRI task designed to elicit RNT. Linear models were employed to examine the interaction between trait RNT and neuroticism and main effects of RNT on brain changes. No significant interaction between trait RNT and neuroticism in relation to DMN and AI recruitment was found. A positive association was observed between trait RNT and recruitment of the precuneus during negative self-referential processing compared to distraction; however, this result did not survive FDR correction for multiple comparisons. Exploratory analyses revealed that responses of the anterior insula during RNT compared to distraction were inversely related to self-reported trait RNT on the trend-level. Our results confirm the relevance of DMN recruitment for RNT and underscore a putative role of the anterior insula. The absence of a significant interaction between RNT and neuroticism may suggest that an alternative conceptualization of their relationship could better capture their underlying dynamics.