Experimental design and the comparison between healthy controls and patients with cervical dystonia. (A) Cortical excitability was quantified with the amplitude of motor potentials evoked with TMS pulses from the primary motor cortex, before and 10, 20, and 30 minutes after the repetitive stimulation. The repetitive stimulation consisted in real or sham stimulation of the cerebellum followed by PAS over M1 and median nerve. (B) The effect of the combined cerebellar and cortical stimulation in healthy controls and cervical dystonia patients are opposite. The effects are evident both when the groups are analyzed as a whole or split in responder and non-responders to PAS. cTBSCB: continuous theta-burst stimulation over the right cerebellar hemisphere; iTBSCB: intermittent theta-burst stimulation over the right cerebellar hemisphere; MEP: motor evoked potential; PAS: paired-associative stimulation; T0-T30: time points before the stimulation and at 10, 20, 30 minutes post-stimulation.