Previous research has highlighted abnormalities in the pulvinar region of the brain among individuals diagnosed with obsessive-compulsive disorder (OCD). Nevertheless, given the pulvinar’s complex structure, comprising four distinct subnuclei (PuA, PuI, PuL, and PuM), inconsistencies persist regarding both structural and connectivity alterations within this region.

3D T1-weighted magnetic resonance imaging (MRI) and resting-state functional magnetic resonance imaging (rs-fMRI) were used on a cohort consisting of 41 healthy controls and 51 individuals with OCD in order to compare pulvinar connectivity and gray matter volume. Our aim was to compare both connectivity patterns and gray matter volume (GMV) within the PuA, PuI, PuL, and PuM subnuclei between the two groups. First, we examined resting-state connectivity differences in these subnuclei, followed by an analysis of GMV discrepancies to elucidate the potential neuropathological role of the pulvinar in OCD.

Our findings revealed significant connectivity differences in the left PuL, the right PuA, and the left PuA between OCD patients and healthy controls (p < 0.05). Furthermore, the left PuA exhibited both connectivity differences and increased GMV in the OCD group after applying multiple comparison corrections (p = 0.002).

Our study identified functional connectivity alterations within specific subnuclei, including the left and right PuA, and the left PuL, alongside GMV changes in the left PuA. These observations suggest that these distinct regions of the pulvinar may contribute to the pathophysiology of OCD through differences in both functional connectivity and GMV compared to healthy controls.