Decoding goal-habit brain networks of OCD from the structural and functional connectivity

Obsessive-Compulsive Disorder (OCD) may involve an imbalance between goal-directed and habitual learning systems, and this study investigates the structural and functional brain networks underpinning these systems in OCD. Using predefined brain regions, structural and functional connectivity networks were constructed, and methods such as network-based statistics, average connectivity strength, structural-functional coupling, and partial least squares path modeling were employed to compare OCD patients and healthy controls. The results revealed that OCD patients showed increased structural connectivity within both the goal-directed and habitual learning networks, particularly in the subnetwork that connects these systems. However, functional connectivity strength was reduced in both the habitual learning network and the subnetwork connecting goal-directed and habitual learning systems. The symptoms of ordering and hoarding are, to some extent, correlated with the structural-functional coupling network and network characteristics. These findings suggest that alterations in both structural and functional brain networks underpin goal-directed and habitual learning in OCD, with increased structural connectivity potentially reflecting compensatory mechanisms, while reduced functional connectivity may contribute to the symptoms of OCD. Further research is required to better understand the complex interplay between these learning systems in OCD, considering symptom heterogeneity and disease's progression.