The effects of 1 Hz rTMS over the hand area of M1 on movement kinematics of the ipsilateral hand

1 Hz rTMS applied over primary motor cortex (M1) reduces cortical excitability outlasting the stimulation period. Healthy right-handed subjects performed finger and hand tapping and a reach-to-grasp movement prior to (baseline) and after 1 Hz rTMS applied over (1) M1 of either the right or the left hemisphere, and (2) the vertex (control stimulation). 1 Hz rTMS applied over the left M1, but not over the vertex, improved movement kinematics of finger and hand tapping as well as grasping with the left hand. 1 Hz rTMS applied over the right M1, but not over the vertex, improved only the kinematics of hand tapping performed with the right hand. These data suggest that 1 Hz rTMS induced inhibition of ipsilateral M1 reduces transcallosal inhibition of contralateral M1 and thereby improves motor performance at the ipsilateral hand. The impact on motor performance of the ipsilateral hand is most pronounced after 1 Hz rTMS over the left M1.