A new study published on September 10 in The Cerebellum provides initial experimental evidence that a single session of cerebellar High - Definition Transcranial Direct Current Stimulation (HD-tDCS) may help maintain anticipatory and consummatory pleasure and enhance reward sensitivity in healthy individuals. The findings highlight the multifaceted role of the cerebellum in reward processing and suggest its potential as a novel target for psychiatric intervention.

Reward processing—an essential mechanism underlying human motivation and emotion regulation—encompasses anticipation, consummatory pleasure, effort-based decision-making, reward sensitivity, and learning. Dysfunctions in these processes manifest as anhedonia and amotivation in disorders such as major depression and schizophrenia, and are also implicated in substance and eating disorders. 

While research has traditionally focused on the mesocorticolimbic reward circuit, converging evidence from human and animal studies indicates that the cerebellum also plays a critical role via modulation of midbrain dopaminergic pathways. Yet, whether cerebellar neuromodulation could directly enhance reward functioning in humans has remained unclear.

To address this question, Dr. Raymond Chan and colleagues from the Neuropsychology and Applied Cognitive Neuroscience (NACN) Laboratory, Institute of Psychology, CAS, conducted a pre-registered randomized, single-blind, pre–post controlled study with 63 healthy adults. Participants were randomly assigned to receive either active or sham HD-tDCS (1.7 mA, 20 minutes) targeting the right posterior cerebellum.

Reward processing was assessed before and after stimulation using three validated paradigms: the Monetary Incentive Delay (MID) task, the adaptive-coding version of the Effort-Expenditure for Rewards Task (EEfRT), and the Probabilistic Selection Task (PST). 

Results showed that the active stimulation group maintained their levels of anticipatory and consummatory pleasure in the MID task, while the sham group exhibited significant declines. Moreover, in the EEfRT, the active group displayed increased reward sensitivity from pre- to post-test, an effect absent in the sham group.

Overall, the present findings suggest that cerebellar HD-tDCS may modulate reward processing in healthy individuals. Although preliminary, these findings open avenues for subsequent studies on its possible relevance to psychiatric disorders marked by altered motivation and pleasure.

This work was supported by the STI2030-Major Projects , the Scientific Foundation of the Institute of Psychology , and the Philip K. H. Wong Foundation.