title: Electric stimulation on human cortex suppresses fast cortical activity and epileptic spikes.
abstract: OBJECTIVE
  To investigate underlying mechanisms and adequate parameters for electric cortical stimulation to inhibit epileptic focus in humans.
  
  
  METHODS
  A patient with intractable partial epilepsy had subdural electrodes implanted for preoperative evaluation. Cortical functional mapping was performed by using 50-Hz alternating square pulse of 0.3-ms duration, 1 to 7 mA, within 5 s. Spike frequency and electrocorticogram (ECoG) power spectra were compared before and after the stimulation when epileptic focus and distant area were stimulated. A similar comparison also was performed in low-frequency stimulation of 0.9 Hz applied for 15 min.
  
  
  RESULTS
  Interictal spikes were reduced after electric cortical stimulation of the epileptic area at a frequency of 50 Hz as well as 0.9 Hz, with concomitant decrease in the electrographic fast activities at 50-Hz stimulation.
  
  
  CONCLUSIONS
  These data suggest that electric cortical stimulation at both high and low frequency has a suppressive effect on epileptic activities in human cortex, possibly through distinct mechanisms.
authors.affiliation: Departments of Neurology, Graduate School of Medicine, Kyoto Universtiy, Kyoto, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Akio
authors.initials: A
authors.lastname: Ikeda
authors.forename: Riki
authors.initials: R
authors.lastname: Matsumoto
authors.forename: Tahamina
authors.initials: T
authors.lastname: Begum
authors.forename: Keiko
authors.initials: K
authors.lastname: Usui
authors.forename: Junichi
authors.initials: J
authors.lastname: Yamamoto
authors.forename: Masao
authors.initials: M
authors.lastname: Matsuhashi
authors.forename: Motohiro
authors.initials: M
authors.lastname: Takayama
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mikuni
authors.forename: Jun
authors.initials: J
authors.lastname: Takahashi
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shibasaki
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology* / Q000503:physiopathology; D004599:Electric Stimulation Therapy / Q000379:methods / Q000706:statistics & numerical data; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000503:physiopathology / Q000517:prevention & control* / Q000628:therapy; D005260:Female; D006801:Humans; D036881:Long-Term Synaptic Depression / Q000502:physiology; D008279:Magnetic Resonance Imaging; D019579:Neocortex / Q000502:physiology / Q000503:physiopathology; D016896:Treatment Outcome; D014741:Video Recording