Modulation of Neural Correlates of Model-based Performance with Impulsivity and Compulsivity

Impaired goal-directed behavior is associated with a range of mental disorders, implicating underlying transdiagnostic factors. While compulsivity has been linked to reduced model-based (MB) control, impulsivity has rarely been studied in the context of reinforcement learning despite its links to reward processing and cognitive control. This study investigated the neural mechanisms underlying MB control and the influence of impulsivity and compulsivity. We analyzed EEG data from 238 individuals during a two-step decision making task. Single-trial analyses revealed that while feedback-related negativity (FRN) amplitudes were higher after common transitions and negative/neutral reward prediction error (RPE), the P3a and P3b were enhanced after rare transitions and both positive and negative RPE. In a second step, we regressed the mean b values of the effect of RPE on the EEG signals onto self-reported impulsivity and compulsivity and weighting parameter w (representing behavioral MB control). The effect of RPE on FRN-related activity was mainly associated with higher w scores. The interaction of impulsivity and w influenced both FRN- and P3a-related activity. The modulation of P3a by RPE was also negatively associated with compulsivity, pointing to a deficient mental model in highly compulsive individuals. Further research is needed to understand these alterations in decision-making processes.