To test the hypothesis, subjects will be randomly allocated to one of 4 experimental sessions (parallel design). Subjects will receive different types of combined brain stimulation (1 Hz rTMS and Theta Burst Stimulation [TBS]) to the right and left MI. The primary outcome measure will be the amount of changes in cortical excitability, as reflected by recruitment curves (RC) of motor evoked potentials (MEPs) elicited by single-pulse TMS over the left MI. Additionally, we will test changes in short-interval intracortical inhibition (SICI) and facilitation (ICF) as well as the modulation of interhemispheric inhibition (IHI) between both MI. The secondary outcome measures will include simple motor tasks such as finger tapping, pinch force/acceleration and reaction time of the right hand.