title: In vivo neuronal firing patterns during human epileptiform discharges replicated by electrical stimulation.
abstract: OBJECTIVE
  To describe neuronal firing patterns observed during human spontaneous interictal epileptiform discharges (IEDs) and responses to single pulse electrical stimulation (SPES).
  
  
  METHODS
  Activity of single neurons was recorded during IEDs and after SPES in 11 consecutive patients assessed with depth EEG electrodes and attached microelectrodes.
  
  
  RESULTS
  A total of 66 neurons were recorded during IEDs and 151 during SPES. We have found essentially similar patterns of neuronal firing during IEDs and after SPES, namely: (a) a burst of high frequency firing lasting less than 100 ms (in 39% and 25% of local neurons, respectively for IED and SPES); (b) a period of suppression in firing lasting around 100-1300 ms (in 19% and 14%, respectively); (c) a burst followed by suppression (in 10% and 12%, respectively); (d) no-change (in 32% and 50%, respectively).
  
  
  CONCLUSIONS
  The similarities in neuronal firing patterns associated with IEDs and SPES suggest that, although both phenomena are initiated differently, they result in the activation of a common cortical mechanism, probably initiated by brief synchronised burst firing in some cells followed by long inhibition.
  
  
  CONCLUSIONS
  The findings provide direct in vivo human evidence to further comprehend the pathophysiology of human focal epilepsy.
authors.affiliation: Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, United Kingdom. gonzalo.alarcon@kcl.ac.uk
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Alarcón
authors.forename: Juan
authors.initials: J
authors.lastname: Martinez
authors.forename: Shashivadan V
authors.initials: SV
authors.lastname: Kerai
authors.forename: Maria E
authors.initials: ME
authors.lastname: Lacruz
authors.forename: Rodrigo Quian
authors.initials: RQ
authors.lastname: Quiroga
authors.forename: Richard P
authors.initials: RP
authors.lastname: Selway
authors.forename: Mark P
authors.initials: MP
authors.lastname: Richardson
authors.forename: Jorge J
authors.initials: JJ
authors.lastname: García Seoane
authors.forename: Antonio
authors.initials: A
authors.lastname: Valentín
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D001921:Brain / Q000473:pathology*; D058256:Brain Waves / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D055815:Young Adult