Phase-Dependent Cerebellar Contributions to Visual Working Memory: An Online Triple-Pulse Transcranial Magnetic Stimulation Study

Introduction The cerebellum is widely viewed as a domain-general modulatory hub within distributed cortico-cerebellar networks, challenging its traditional classification as a solely motor structure. Accumulating evidence shows the cerebellum’s involvement in a wide range of nonmotor domains, including working memory (WM) as a central component of executive functions. Although evidence suggests that cerebellar engagement varies dynamically across working memory phases, this postulate has not yet been investigated using temporally precise, phase-specific neuromodulation. By temporally aligning cerebellar stimulation with distinct WM phases, thisx work aims to study how cerebellar neuromodulation differentially influences maintenance and retrieval processes within visuospatial working memory tasks. Objectives The main purpose of this study is to explore the phase-specific involvement of the cerebellum in visuospatial WM (VWM) using online transcranial magnetic stimulation (TMS) applied during a forward Corsi block-tapping task (CBTT) performance. Materials and Methods A total of 38 healthy participants participated in the study, using a within-subjects, repeated-measures design to examine the phase-specific contribution of the cerebellum to VWM. Participants completed the CBTT, while applying TMS “online,” under four experimental conditions, resulting from the factorial combination of two stimulation sites (cerebellum vs vertex) and two task phases (maintenance vs retrieval). Results Cerebellar stimulation disrupted performance (slower response times, lower accuracy) during the retrieval phase; however, it increased memory span during the maintenance phase. Conclusions Findings show that the cerebellum contributes to VWM in a phase-specific manner. Cerebellar involvement appears to be facilitative during maintenance and disruptive during retrieval, indicating distinct functional roles across WM stages.