Transcranial direct current stimulation of the motor cortex induces distinct changes in thermal and mechanical sensory percepts.
OBJECTIVE
The aim of this single-blinded, complete crossover study was to evaluate the effects of tDCS on thermal and mechanical perception, as assessed by quantitative sensory testing (QST).


METHODS
QST was performed upon the radial part of both hands of eight healthy subjects (3 female, 5 male, 25-41years of age). These subjects were examined before and after cathodal, anodal or sham tDCS, applied in a random order. TDCS was administered for 15min at a 1mA current intensity, with the active electrode placed over the left primary motor cortex and the reference electrode above the right orbit.


RESULTS
After cathodal tDCS, cold detection thresholds (CDT), mechanical detection thresholds (MDT), and mechanical pain thresholds (MPT) significantly increased in the contralateral hand, when compared to the baseline condition.


CONCLUSIONS
Cathodal tDCS temporarily reduced the sensitivity to A-fiber mediated somatosensory inputs.


CONCLUSIONS
Impairment of these somatosensory percepts suggests a short-term suppression of lemniscal or suprathalamic sensory pathways following motor cortex stimulation by cathodal tDCS.
Bachmann
Cornelius G
CG
Department of Clinical Neurophysiology, Georg August-University, Goettingen, Germany. cbachma@gwdg.de
Muschinsky
Sebastian
S
Nitsche
Michael A
MA
Rolke
Roman
R
Magerl
Walter
W
Treede
Rolf-Detlef
RD
Paulus
Walter
W
Happe
Svenja
S
D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D011930:Reaction Time; D012684:Sensory Thresholds / Q000502:physiology; D017603:Signal Detection, Psychological / Q000502:physiology; D016037:Single-Blind Method; D013697:Thermosensing / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*