title: Transcranial direct current stimulation over the opercular somatosensory region does not influence experimentally induced pain: a triple blind, sham-controlled study.
abstract: Transcranial magnetic stimulation (TMS) over the opercular somatosensory region (OP), which includes the secondary somatosensory cortex and the insular cortex, suppresses pain sensation. However, whether transcranial direct current stimulation (tDCS) over the OP has a similar effect on pain sensation remains unknown. We examined whether pain sensation would be suppressed by tDCS over the OP. Our experiment with a triple-blind, sham-controlled, crossover design involved 12 healthy participants. Participants were asked to rate their subjective pain intensity during and after three types of bihemispheric tDCS: right anodal/left cathodal OP tDCS, left anodal/right cathodal OP tDCS (2 mA, 12 min), and sham tDCS (15 s). Pain stimuli were alternately applied to the dorsum of each index finger using intraepidermal electrical stimulation. We observed no significant effect of tDCS over the OP on the perception of experimentally induced pain. Subjective pain intensity did not differ significantly between the three tDCS conditions. The present null results have crucial implications for the selection of optimal stimulation regions and parameters for clinical pain treatment.
authors.affiliation: aFaculty of Rehabilitation, School of Health Sciences, Fujita Health University, Toyoake bDepartment of Cerebral Research, Division of Cerebral Integration, National Institute for Physiological Sciences, Okazaki cDivision of Bio-Environmental Adaptation Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima dLaboratory of Psychology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Koyama
authors.forename: Kei
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000209:etiology / Q000473:pathology*; D059408:Pain Management; D010147:Pain Measurement; D017288:Pain Threshold; D013003:Somatosensory Cortex / Q000502:physiology*; D011795:Surveys and Questionnaires; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult