Disorganized thalamic subregional functional connectivity in bipolar I disorder

Thalamus plays a pivotal role in the pathophysiology of neuropsychiatric conditions due to its strategic position and intricate connectivity with the cerebral cortex, limbic system, and other subcortical structures. In the present study, the potential involvement of the thalamus and subregions of the thalamus are explored in bipolar disorder (BD). In particular, functional and structural magnetic resonance imaging was performed on 73 adult patients with BD-I and 78 healthy controls (HCs). Seed-based thalamus and thalamic subregional functional connectivity (FC) were compared between the BD-I patients and HCs. Compared to HCs, patients with BD-I showed higher FC between the left thalamus and right lingual gyrus and altered FC between the dorsal thalamus and the default mode network and prefrontal regions, which may be correlated with mania symptomatology. In patients with BD-I, the anterior subregions of the thalamus had higher FC than the posterior subregions. No significant difference in gray matter volume or local functional activity was found in the thalamus and thalamic subregions between BD-I and HC. These findings provide evidence of disorganized thalamocortical FC in BD-I, suggesting that the thalamus and its subregions may play important and specific roles in the neural circuitry of BD.