Fig. 1

Experimental arrangement and the position of electrodes during tDCS. a Experimental arrangement. Before induction of repetitive mTBI (day 1), MEP and behavioral tests are performed on the rat model. After pre-mTBI tests, the first mTBI is induced in the rat models. On days 2 and 3, second and third mTBI is induced in the rats to establish the repetitive mTBI rat models. After the third mTBI, MEP, and motor coordination studies are done (day 3). On day 4, anodal tDCS at M1 area is applied to the tDCS group. On day 4, 1 h after tDCS, MEP is done. On day 5, behavioral tests and brain MRI are done. b The position of anodal and cathodal electrodes during anodal tDCS. Circle means anodal electrode and square means cathodal electrode. Cup-shaped anodal electrode was attached to the skin over the left M1 area, and rectangular rubber cathodal electrode was positioned on the trunk