Cerebellum helps mice anticipate rewards, not just coordinate movement
NIH and Brown University researchers studied mice to examine the cerebellum's role in reward learning. Imaging showed many granule cells activated while animals anticipated reward, while climbing fibers responded to reward delivery. Suppressing granule cells during the delay impaired learning and execution, and activating climbing fibers reinforced behavior.
NIH and Brown University scientists trained mice to push a handle for delayed stimulation of dopamine-linked reward circuits, with no food or drink. This avoided mixing reward signals with consumption-related activity.
Imaging showed granule cells firing as mice awaited reward, while climbing fibers reacted at delivery. Blocking granule cells during the wait impaired learning and execution; stimulating climbing fibers reinforced pushing at moderate rates. The study appeared in Nature Neuroscience.
This finding may broaden how scientists view the cerebellum, potentially influencing future research into reward learning and compulsive behaviors. People affected by substance use disorders or other conditions involving reward-seeking could eventually benefit if the work helps identify new neural targets. Clinicians and neuroscientists may also use these insights to refine models of motivation and learning. However, mouse studies require caution before human applications are assumed.