Left cerebellar transcranial direct current stimulation facilitates the onset of inhibition of return

Abstract

Over the past 20 years our knowledge of the functional role of the cerebellum has evolved from that of a structure strictly involved in coordinating motor outputs, to one that is also heavily engaged in cognitive functions, including attention. Specifically, patient work indicates that cerebellar damage slows rapid shifts of reflexive covert attention, as well as the onset of inhibition of return (IOR). In addition, fMRI studies suggest that the left lateral cerebellum may play an important role in covert attention. In the current study we further examined the role of cerebellum in covert attention using transcranial direct current stimulation (tDCS) where a weak electrical current is applied to electrodes on the scalp to induce changes in baseline neural activity in the underlying cortex. Participants (n=23) completed a reflexive covert attention task using stimulus onset asynchronies (SOAs) of 50, 100, 300, and 600ms before, during, and after either anodal (+), cathodal (-), or sham tDCS applied to the left cerebellum (2mA for 20min). Results indicated that active tDCS stimulation facilitated the onset of IOR at the longest SOA compared to sham. Our results provide further evidence that the left lateral cerebellum plays an important role in reflexive covert visual attention.

Faculty Mentor: Christopher Striemer

Department: Psychology