['To investigate the effect of the voluntary movement on the amplitude of the somatosensory evoked potentials (SEPs) recorded by an epidural electrode at level of the cervical spinal cord (CSC).', "Fourteen patients underwent an epidural electrode implant at CSC level for pain relief. After the median nerve stimulation, SEPs were recorded from the epidural electrode and from 4 surface electrodes (in frontal and parietal regions contralateral to the stimulated side, over the 6th cervical vertebra, and on the Erb's point). SEPs were recorded at rest and during a voluntary flexo-extension movement of the stimulated wrist. Beyond the low-frequency SEPs, also the high-frequency oscillations (HFOs) were analysed.", 'The epidural electrode contacts recorded a triphasic potential (P1-N1-P2), whose negative peak showed the same latency as the cervical N13 response. The epidural potential amplitude was significantly decreased during the voluntary movement, as compared to the rest. Two main HFOs were identifiable: (1) the 1200 Hz HFO which was significantly lower in amplitude during movement than at rest, and (2) the 500 Hz HFO which was not modified by the voluntary movement.'] Do unmasking of presynaptic and postsynaptic high-frequency oscillations in epidural cervical somatosensory evoked potentials during voluntary movement?