title: Primary motor cortex activation by transcranial direct current stimulation in the human brain.
abstract: Transcranial direct current stimulation (tDCS) can modulate motor cortex excitability in the human brain. We attempted to demonstrate the cortical stimulation effect of tDCS on the primary motor cortex (M1) using functional MRI (fMRI). An fMRI study was performed for 11 right-handed healthy subjects at 1.5 T. Anodal tDCS was applied to the scalp over the central knob of the M1 in the left hemisphere. A constant current with an intensity of 1.0 mA was applied. The total fMRI paradigm consisted of three sessions with a 5-min resting period between each session. Each session consisted of five successive phases (resting-tDCS-tDCS-tDCS-tDCS), and each of the phases was performed for 21s. Our findings revealed that no cortical activation was detected in any of the stimulation phases except the fourth tDCS phase. In the result of group analysis for the fourth tDCS phase, the average map indicated that the central knob of the left primary motor cortex was activated. In addition, there were activations on the left supplementary motor cortex and the right posterior parietal cortex. We demonstrated that tDCS has a direct stimulation effect on the underlying cortex. It seems that tDCS is a useful modality for stimulating a target cortical region.
authors.affiliation: Department of Physical Therapy, Yeungnam College of Science and Technology, Republic of Korea.
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Kwon
authors.forename: Myoung-Hwan
authors.initials: MH
authors.lastname: Ko
authors.forename: Sang Ho
authors.initials: SH
authors.lastname: Ahn
authors.forename: Yun-Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Jun Chan
authors.initials: JC
authors.lastname: Song
authors.forename: Chu-Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Min Cheol
authors.initials: MC
authors.lastname: Chang
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Jang
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology; D004599:Electric Stimulation Therapy / Q000379:methods*; D004560:Electricity; D004582:Electronics, Medical / Q000295:instrumentation / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D011712:Pyramidal Tracts / Q000502:physiology; D016896:Treatment Outcome