The role of the medial cerebellum in modulating empathic accuracy: a tACS study

The cerebellum, traditionally associated with motor functions, has recently been recognized as a structure also involved in cognitive and socio-emotional processes. However, its specific contribution to empathy is still poorly understood. The present study investigated the causal contribution of the medial cerebellum to empathic accuracy, assessing whether transcranial alternating current stimulation (tACS) at gamma and theta frequencies could modulate performance at the Empathic Accuracy Task (EAT), in which participants are asked to rate other people’s emotional states while watching short autobiographical videos with positive or negative valence. Thirty participants completed the EAT under three stimulation conditions over the medial cerebellum: gamma-tACS, theta-tACS, and sham (control). tACS did not significantly modulate empathic accuracy, nor did a significant interaction between tACS condition and video valence emerge. A significant effect of video valence was observed, with higher empathic accuracy for positive videos compared to negative ones. Regarding valence ratings, a significant effect of video valence and a significant interaction between tACS condition and video valence were observed, although no significant differences between tACS conditions emerged in the simple effects analysis. Overall, these results contribute to clarifying the role of the cerebellum in empathic processing and provide a basis for further investigations of cerebellar mechanisms involved in empathy. Key words: cerebellum; empathy; transcranial alternating current stimulation; empathic accuracy.