Individuals with internet gaming disorder (IGD) are generally characterized by impaired executive control, persistent game-craving, and excessive reward-seeking behaviors. However, the causal interactions within the frontostriatal circuits underlying these problematic behaviors remain unclear. Here, spectral dynamic causal modeling (spDCM) was implemented to explore this issue.

Resting-state functional magnetic resonance imaging data from 317 online game players (148 IGD subjects and 169 recreational game users (RGUs)) were collected. Using independent component analysis, we determined six region of interests within frontostriatal circuits for further spDCM analysis, and further statistical analyses based on the parametric empirical Bayes framework were performed.

Compared with RGUs, IGD subjects showed inhibitory effective connectivity from the right orbitofrontal cortex (OFC) to the right caudate and from the right dorsolateral prefrontal cortex to the left OFC; at the same time, excitatory effective connectivity was observed from the thalamus to the left OFC. Correlation analyses results showed that the directional connection from the right OFC to the right caudate was negatively associated with addiction severity.

These results suggest that the disrupted causal interactions between specific regions might contribute to dysfunctions within frontostriatal circuits in IGD, and the pathway from the right OFC to the right caudate could serve as a target for brain modulation in future IGD interventions.

Autism spectrum disorder (ASD) and obsessive–compulsive disorder (OCD) are neurodevelopmental disorders with considerable overlap in terms of their defining symptoms of compulsivity/repetitive behaviour. Little is known about the extent to which ASD and OCD have common versus distinct neural correlates of compulsivity. Previous research points to potentially common dysfunction in frontostriatal connectivity, but direct comparisons in one study are lacking. Here, we assessed frontostriatal resting-state functional connectivity in youth with ASD or OCD, and healthy controls. In addition, we applied a cross-disorder approach to examine whether repetitive behaviour across ASD and OCD has common neural substrates.

A sample of 78 children and adolescents aged 8–16 years was used (ASD n = 24; OCD n = 25; healthy controls n = 29), originating from the multicentre study COMPULS. We tested whether diagnostic group, repetitive behaviour (measured with the Repetitive Behavior Scale-Revised) or their interaction was associated with resting-state functional connectivity of striatal seed regions.

No diagnosis-specific differences were detected. The cross-disorder analysis, on the other hand, showed that increased functional connectivity between the left nucleus accumbens (NAcc) and a cluster in the right premotor cortex/middle frontal gyrus was related to more severe symptoms of repetitive behaviour.

We demonstrate the fruitfulness of applying a cross-disorder approach to investigate the neural underpinnings of compulsivity/repetitive behaviour, by revealing a shared alteration in functional connectivity in ASD and OCD. We argue that this alteration might reflect aberrant reward or motivational processing of the NAcc with excessive connectivity to the premotor cortex implementing learned action patterns.