Fig. 4.

Percentage change in MEP amplitude following practice on the ballistic thumb acceleration task combined with online TDCS. Application of TDCS in a PA current direction reversed the normal effect of practice (i.e. sham TDCS) on MEPs in the agonist muscle (abductor pollicis brevis). TDCS applied in the opposite AP current direction had no overall effect. Overall, changes in MEPs were similar when evoked with PA and AP TMS currents. MEPs in uninvolved abductor digiti minimi muscle were unaffected by motor practice and TDCS. **P < 0.01.