The Effect of Cerebellar tDCS On Inhibitory Control in Healthy Adults: Exploring Trait Moderation

Transcranial direct current stimulation (tDCS) research on inhibitory control (IC) has largely focused on prefrontal targets, with inconsistent results, while the cerebellum's contribution to executive control networks remains underexplored. This study examines whether cerebellar anodal tDCS modulates IC in healthy adults, using both proactive (Go/No-Go) and reactive (Stop Signal) inhibition measures, and explores whether dispositional traits moderate stimulation effects. In a double-blind, sham-controlled, within-subjects design, 40 participants received active and sham cerebellar tDCS (2 mA, 20 min, anodal, left cerebellum) across two sessions. IC was assessed via reaction time and No-Go accuracy on the Go/No-Go task and Stop Signal Reaction Time (SSRT) on the Stop Signal Task. Exploratory analyses tested whether trait impulsivity, effortful control, and behavioral inhibition/approach tendencies (BIS/BAS) moderated stimulation effects. Stimulation did not appear to affect Go/No-Go reaction time, No-Go accuracy, or SSRT. Exploratory analyses revealed a mixed pattern of trait-dependent effects: active stimulation amplified pre-existing associations between dispositional traits and Go/No-Go responding, with higher trait impulsivity linked to faster responding and higher effortful control linked to slower responding. Reward sensitivity (Behavioral Approach Scale) showed no association under sham but predicted both faster responding and reduced No-Go accuracy under active stimulation. Left anodal cerebellar tDCS produced no group-level enhancement of IC. However, exploratory analyses suggested that individual differences may shape responsiveness to stimulation. Future research with larger, trait-stratified samples is needed to confirm these patterns and clarify whether cerebellar tDCS selectively benefits specific subgroups.