title: The impact of cerebellar transcranial direct current stimulation (tDCS) on learning fine-motor sequences.
abstract: The cerebellum has been shown to be important for skill learning, including the learning of motor sequences. We investigated whether cerebellar transcranial direct current stimulation (tDCS) would enhance learning of fine motor sequences. Because the ability to generalize or transfer to novel task variations or circumstances is a crucial goal of real world training, we also examined the effect of tDCS on performance of novel sequences after training. In Study 1, participants received either anodal, cathodal or sham stimulation while simultaneously practising three eight-element key press sequences in a non-repeating, interleaved order. Immediately after sequence practice with concurrent tDCS, a transfer session was given in which participants practised three interleaved novel sequences. No stimulation was given during transfer. An inhibitory effect of cathodal tDCS was found during practice, such that the rate of learning was slowed in comparison to the anodal and sham groups. In Study 2, participants received anodal or sham stimulation and a 24 h delay was added between the practice and transfer sessions to reduce mental fatigue. Although this consolidation period benefitted subsequent transfer for both tDCS groups, anodal tDCS enhanced transfer performance. Together, these studies demonstrate polarity-specific effects on fine motor sequence learning and generalization.This article is part of the themed issue 'New frontiers for statistical learning in the cognitive sciences'.
authors.affiliation: Department of Psychology, University of California, Los Angeles, CA 90095, USA.
authors.forename: Renee E
authors.identifier: 0000-0002-0567-5678
authors.initials: RE
authors.lastname: Shimizu
authors.affiliation: Department of Neurology, University of California, Los Angeles, CA 90095, USA.
authors.forename: Allan D
authors.initials: AD
authors.lastname: Wu
authors.affiliation: Department of Psychology, University of California, Los Angeles, CA 90095, USA.
authors.forename: Jasmine K
authors.initials: JK
authors.lastname: Samra
authors.affiliation: Department of Psychology, University of California, Los Angeles, CA 90095, USA knowlton@psych.ucla.edu.
authors.forename: Barbara J
authors.identifier: 0000-0002-1532-5081
authors.initials: BJ
authors.lastname: Knowlton
mesh_terms: D000293:Adolescent; D000328:Adult; D002531:Cerebellum / Q000502:physiology*; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D009048:Motor Skills; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
keywords: cerebellum; motor skill learning; sequence learning; transcranial direct current stimulation