title: Further evidence that pathologic high-frequency oscillations are bursts of population spikes derived from recordings of identified cells in dentate gyrus.
abstract: OBJECTIVE
  To analyze activity of identified dentate gyrus granular cells and interneurons during pathologic high-frequency oscillations (pHFOs).
  
  
  METHODS
  Pilocarpine-treated epileptic mice were anesthetized with urethane and ketamine. Their heads were fixed in a stereotaxic frame. Extracellular unit activity was recoded with glass micropipettes, whereas multiunit and local field activity was simultaneously recorded with attached tungsten microelectrodes. After electrophysiologic experiments, recorded cells were labeled by neurobiotin and visualized by immunohistochemical methods. KEY FINDINGS AND SIGNIFICANCES: pHFOs containing more than three waves were recorded in our experiments, but pathologic single-population spikes also occurred. Identified granular cells discharged preferentially in synchrony with pHFOs and single population spikes, whereas interneurons decreased their discharge frequency during this time. These experiments provide additional confirmation that pHFOs in the dentate gyrus represent single or recurrent population spikes, which in turn reflect summated hypersynchronous discharges of principal cells.
authors.affiliation: Department of Neurology The Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. abragin@ucla.edu
authors.forename: Anatol
authors.initials: A
authors.lastname: Bragin
authors.forename: Simone K
authors.initials: SK
authors.lastname: Benassi
authors.forename: Farshad
authors.initials: F
authors.lastname: Kheiri
authors.forename: Jerome
authors.initials: J
authors.lastname: Engel
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D018891:Dentate Gyrus / Q000166:cytology* / Q000473:pathology / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL