The purpose of this study is to investigate the cortical center for voluntary control of eyelid closure using transcranial magnetic stimulation (TMS). Conventionally the primary motor cortex (M1) has been thought to control upper facial movement . However, recent neuroanatomical and neuroimaging studies suggest that the upper facial muscles are mainly controlled by the mesial frontal region, not M1 . Recently, we performed a transcranial magnetic stimulation (TMS) study to investigate the cortical center for the upper facial muscles, especially those related to blinking, and observed possible cortical responses from the surface electrodes attached to the orbicularis oculi (OOC) muscles with the stimulation applied to the mesial frontal region. In this study, we are planning to use monopolar needle electrodes to confirm that these responses originate from the cortical stimulation.