In this study, the role of the cerebellum in a cognitive learning task using transcranial direct current stimulation (tDCS) was investigated. Using a weather prediction task, subjects had to learn the probabilistic associations between a stimulus (a combination of cards) and an outcome (sun or rain). This task is a variant of a probabilistic classification learning task, for which it has been reported that prefrontal tDCS enhances performance. Using a between-subject design, all 30 subjects learned to improve their performance with increasing accuracies and shortened response times over a series of 500 trials. Subjects also became more confident in their prediction during the experiment. However, no differences in performance and learning were observed between subjects receiving sham stimulation (n = 10) or anodal stimulation (2 mA for 20 min) over either the right cerebellum (n = 10) or the left prefrontal cortex (n = 10). This suggests that stimulating the brain with cerebellar tDCS does not readily influence probabilistic classification performances, probably due to the rather complex nature of this cognitive task.

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Experimental Brain Research
Department of Neuroscience

Seyed Majidi, N., Verhage, C., Donchin, O., Holland, P., Frens, M., & van der Geest, J. (2016). Cerebellar tDCS does not improve performance in probabilistic classification learning. Experimental Brain Research, (235), 412–428. doi:10.1007/s00221-016-4800-8