title: Enhanced accuracy in novel mirror drawing after repetitive transcranial magnetic stimulation-induced proprioceptive deafferentation.
abstract: When performing visually guided actions under conditions of perturbed visual feedback, e.g., in a mirror or a video camera, there is a spatial conflict between visual and proprioceptive information. Recent studies have shown that subjects without proprioception avoid this conflict and show a performance benefit. In this study, we tested whether deafferentation induced by repetitive transcranial magnetic stimulation (rTMS) can improve mirror tracing skills in normal subjects. Hand trajectory error during novel mirror drawing was compared across two groups of subjects that received either 1 Hz rTMS over the somatosensory cortex contralateral to the hand or sham stimulation. Mirror tracing was more accurate after rTMS than after sham stimulation. Using a position-matching task, we confirmed that rTMS reduced proprioceptive acuity and that this reduction was largest when the coil was placed at an anterior parietal site. It is thus possible, with rTMS, to enhance motor performance in tasks involving a visuoproprioceptive conflict, presumably by reducing the excitability of somatosensory cortical areas that contribute to the sense of hand position.
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark. daniela@nru.dk
authors.forename: Daniela
authors.initials: D
authors.lastname: Balslev
authors.forename: Lars O D
authors.initials: LO
authors.lastname: Christensen
authors.forename: Ji-Hang
authors.initials: JH
authors.lastname: Lee
authors.forename: Ian
authors.initials: I
authors.lastname: Law
authors.forename: Olaf B
authors.initials: OB
authors.lastname: Paulson
authors.forename: R Christopher
authors.initials: RC
authors.lastname: Miall
mesh_terms: D000293:Adolescent; D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010812:Physical Stimulation / Q000379:methods; D011434:Proprioception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D014796:Visual Perception / Q000502:physiology