Anodal motor cortex stimulation paired with movement repetition increases anterograde interference but not savings
Eur J Neurosci. 2014-08-27; 40(8): 3243-3252
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1. Eur J Neurosci. 2014 Oct;40(8):3243-52. doi: 10.1111/ejn.12699. Epub 2014 Aug 27.
Anodal motor cortex stimulation paired with movement repetition increases
anterograde interference but not savings.
Leow LA(1), Hammond G, de Rugy A.
(1)School of Psychology, The University of Western Australia, 35 Stirling
Highway, Crawley, WA, 6009, Australia; The Brain and Mind Institute, University
of Western Ontario, London, ON, Canada, N6A 5B7.
Retention of motor adaptation is evident in savings, where initial learning
improves subsequent learning, and anterograde interference, where initial
learning impairs subsequent learning. Previously, we proposed that use-dependent
movement biases induced by movement repetition contribute to anterograde
interference, but not to savings. Here, we evaluate this proposal by limiting or
extending movement repetition while stimulating the motor cortex (M1) with anodal
transcranial direct current stimulation (tDCS), a brain stimulation technique
known to increase use-dependent plasticity when applied during movement
repetition. Participants first adapted to a counterclockwise rotation of visual
feedback imposed either abruptly (extended repetition) or gradually (limited
repetition) in a first block (A1), during which either sham or anodal tDCS (2 mA)
was applied over M1. Anterograde interference was then assessed in a second block
(B) with a clockwise rotation, and savings in a third block (A2) with a
counterclockwise rotation. Anodal M1 tDCS elicited more anterograde interference
than sham stimulation with extended but not with limited movement repetition.
Conversely, anodal M1 tDCS did not affect savings with either limited or extended
repetition of the adapted movement. Crucially, the effect of anodal M1 tDCS on
anterograde interference did not require large errors evoked by an abrupt
perturbation schedule, as anodal M1 tDCS combined with extended movement
repetition within a gradual perturbation schedule similarly increased anterograde
interference but not savings. These findings demonstrate that use-dependent
plasticity contributes to anterograde interference but not to savings.
© 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
PMID: 25160706 [Indexed for MEDLINE]