INTRODUCTION: Semantic memory retrieval is a fundamental cognitive function underlying adaptive behavior. Although accumulating evidence implicates the cerebellum in semantic processing and retrieval, its specific functional contribution remains unclear.

AIM(S): We tested the hypothesis that the right posterior cerebellum supports automatic (associative) memory retrieval rather than executive retrieval control.

METHOD(S): We conducted a double-blind, randomized controlled trial in which healthy adults completed free-associative (automatic) and dissociative (controlled) word retrieval tasks before and during either anodal or sham transcranial direct current stimulation (tDCS) targeting the right posterior cerebellum. The experiment additionally manipulated selection and switching demands, enabling a more process-sensitive assessment of retrieval dynamics.

RESULTS: Anodal cerebellar tDCS selectively impaired free-associative retrieval, while exerting no significant effect on retrieval control measures. Further analyses revealed that the disruption of free-associative performance was most pronounced in trials with cue words eliciting strong, dominant associations, compared to cues evoking a broader set of weaker word associations.

CONCLUSIONS: These findings provide evidence that the cerebellum contributes to automatic semantic retrieval, specifically by facilitating the activation of habitual, well-established conceptual associations. This role is consistent with the view of the cerebellum as a structure involved in the formation of habitual patterns and predictions across multiple domains, including memory, language, and higher cognition.

FINANCIAL SUPPORT: APVV-23-0145, VEGA 2/0052/23, DoktoGrant APP0598