Background: Compelling animal research evidence has shown direct links between the cerebellum (CB) and the dopaminergic ventral tegmental area (VTA) in motivated social behavior. Prior evidence has pointed to BOLD signal variability (BSV) as a proxy of neural dopaminergic signaling. However, whether the CB-VTA circuitry is involved in social motivation deficits (asociality) is poorly understood in schizophrenia (SZ).

Methods: We employed a whole brain BSV approach in 47 matched healthy controls and SZ patients (25 SZ) with a partial least correlation analysis to derive multivariate brain patterns associated with motivation deficits assessed with the Self-Evaluation of Negative Symptoms scale. We examined the functional connectivity of cerebellar subfields (using SUIT, a spatial unbiased atlas template of cerebellum) to the VTA linked to social motivation deficits.

Results: Whole brain multivariate analysis revealed an overall reduced BSV in patients (p¼0.003). BSV increases in the CB and superior prefrontal cortex were associated with more severe asociality in both groups (p < .05 FDR corrected). Hyperconnectivity between the VTA and Crus I (bilaterally) and II (right) as well as to posterior vermis was associated with more severe asociality in all participants, however more pronounced in the SZ cohort.

Conclusions: Our preliminary results point to significantly higher cerebellar BSV associated with more severe social motivation deficits, in addition to a hyperconnectivity between the VTA and the lateral and posterior CB. Overall, our findings provide support for a role of the cerebellum to social motivation deficits, possibly via its connection to the midbrain VTA.