Effects of anodal tDCS on lumbar propriospinal system in healthy subjects

Objective: It has recently been shown that transcranial direct current stimulation (tDCS) (1) can modify lumbar spinal network excitability and (2) decreases cervical propriospinal system excitability. Thus the purpose of this series of experiments was to determine if anodal tDCS applied over the leg motor cortex area induces changes in lumbar propriospinal system excitability. To that end, the effects of anodal tDCS and sham tDCS on group I and group II propriospinal facilitation of quadriceps motoneurones were studied in healthy subjects. Methods: Common peroneal nerve group I and group II quadriceps H-reflex facilitation was assessed in 15 healthy subjects in two randomised conditions: anodal tDCS condition and sham tDCS condition. Recordings were performed before, during and after the end of the cortical stimulation. Results: Compared to sham, anodal tDCS decreases significantly CPN-induced group I and II quadriceps H-reflex facilitation during and also after the end of the cortical stimulation. Conclusions: Anodal tDCS induces (1) modulation of lumbar propriospinal system excitability (2) post-effects on spinal network. Significance: These results open a new vista to regulate propriospinal lumbar system excitability in patients and suggest that anodal tDCS would be interesting for neuro-rehabilitation of patients with central nervous system lesions. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.