Transcranial direct current stimulation over the left motor area influenced both contralateral and ipsilateral finger sequence movements in seven healthy adults. Effects for the two hands were reversed: anodal stimulation improved right-hand performance significantly more than cathodal stimulation, whereas cathodal stimulation improved left-hand performance significantly more than anodal stimulation. The results show that stimulating a motor region directly, or indirectly by modulating activity in the homologous region on the opposite hemisphere, can affect motor skill acquisition, presumably by facilitating effective synaptic connectivity. This outcome provides evidence for the role of interhemispheric inhibition in corticomotor functioning, and also has implications for treatment methods aimed at facilitating motor recovery after stroke.
Neuroimaging Laboratory, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
Correspondence and requests for reprints to Dr Gottfried Schlaug, Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
Tel: +1 617 632 8912; fax: +1 617 632 8920; e-mail: firstname.lastname@example.org
Sponsorship: This work was supported by grants from the National Institute of Neurological Disorders and Stroke to B.W.V. (NS053326) and to G.S. (NS045049). G.S. also acknowledges support from the Doris Duke Charitable Foundation.
Received 1 February 2006; accepted 3 February 2006