We examined the effects of a sensory trick (SeT) on cortical EEG and globus pallidus (GP) local field potentials in four cervical dystonia patients, two of whom had an effective SeT and two who did not. The application of an effective SeT was associated with bilateral desynchronization in the 6-8 Hz and beta bands in the GP and sensorimotor cortical regions. In contrast, mimicking an SeT led to a worsening of dystonia, which was associated with desynchronization of the beta band and synchronization in the 4-6 Hz range. These preliminary findings suggest a role for 4-8 Hz frequency synchronization in the pathophysiology of dystonia.