The imbalance between goal-directed and habitual systems in internet gaming disorder: Results from the disturbed thalamocortical communications.

Abstract Background Converging evidence has identified the imbalance between goal-directed systems and habitual systems in the addiction process. The thalamocortical loop plays an important role in the habitual/goal-directed system. However, little is known about the role of the thalamus in goal-directed and habitual systems in Internet gaming disorder (IGD) patients. This study investigated whether thalamocortical circuit was disrupted and how they affected goal-directed and habitual behaviors in IGD patients. Methods This is a functional magnetic resonance imaging (fMRI) study. Twenty-five IGD patients and 25 matched recreational game users (RGUs) were scanned when they were in a resting state and were performing an instrumental learning task to obtain behavioral data related to habitual/goal-directed behavior. We used the whole-brain seed-based functional connectivity (FC) of the four thalamic nuclei (bilateral) and correlation analyses to examine the thalamocortical loop difference and relationship with habitual/goal-directed performance. Results Compared with RGUs, IGD patients demonstrated significantly increased FC between the left midline nucleus (MN) and the right postcentral gyrus (PCG), and between the pulvinar and medial frontal gyrus (MFG). Correlation results showed that within the IGD group, the correct response rates of the participants to inconsistent stimulus-result pairs were positively correlated with the FC between the pulvinar and MFG. Inhibition-control scores were negatively correlated with the FC between the left MN and the PCG. Conclusions IGD patients showed disrupted thalamocortical communication that could further result in an imbalance between the goal-directed and habitual systems in IGD patients. These findings provide more information about the involvement of the thalamus in the pathophysiology of IGD, and as potential circuit-level biomarkers of IGD patients, these circuit alterations may be useful in treatment development and in monitoring treatment outcomes.