Title : Restless bandit test reveals a cerebellar role in adaptive decision-making
Abstract:
The cerebellum is classically associated with movement coordination, equilibrium, and balance, but emerging evidence suggests it also contributes to cognitive processes through its communication with the cerebrum. This study examined the role of the cerebellum in reward-based decision-making—specifically, the trade-off between exploiting a current reward source and exploring alternative ones. We compared exploit/explore decision-making in healthy mice and a mouse model with Purkinje cell–specific loss of glucocorticoid receptors (GRKO). Fifteen mice (7 control, 8 GRKO) completed the Restless Bandit task, administered over 48 days via the Feeding Experimentation Device (FED3). This task probes the trade-off between exploration and exploitation in decision-making. Our results indicate that GRKO mice exhibit an exploitation bias in decision-making. More subtle behavioral changes show GRKO mice were less active in modulating their behavior across the circadian cycle and showed a higher tendency to persist after receiving a reward, particularly during the dark phase. Together, these findings suggest that cerebellar glucocorticoid receptor knockout alters multiple aspects of decision-making—shifting explore/exploit behavior, increasing reward-driven persistence, and dampening circadian modulation of activity. Notably, this behavioral profile parallels features observed in human schizophrenia, a disorder long correlated with cerebellar neuropathology, though that association has remained purely correlational. Our experimental approach is designed to investigate the underlying mechanisms and establish potential causal relationships between cerebellar function and schizophrenia-relevant behavior.
