title: Abnormal UP/DOWN Membrane Potential Dynamics Coupled with the Neocortical Slow Oscillation in Dentate Granule Cells during the Latent Phase of Temporal Lobe Epilepsy.
abstract: The dentate gyrus, a major entry point to the hippocampus, gates (or filters) incoming information from the cortex. During sleep or anesthesia, the slow-wave oscillation (SWO) orchestrates hippocampus-neocortex communication, which is important for memory formation. The dentate gate is altered in temporal lobe epilepsy (TLE) early during epileptogenesis, which favors the propagation of pathological activities. Yet, whether the gating of physiological SWO by dentate granule cells (DGCs) is altered in TLE has remained unexplored. We combined intracellular recordings of membrane potential (V m) of DGCs and local field potential recordings of the SWO in parietal cortex in anesthetized rats early during epileptogenesis [post-status epilepticus (SE) rats]. As expected, in control rats, the V m of DGCs weakly and rarely oscillated in the SWO frequency range. In contrast, in post-SE rats, the V m of DGCs displayed strong and long-lasting SWO. In these cells, clear UP and DOWN states, in phase with the neocortical SWO, led to a bimodal V m distribution. In post-SE rats, the firing of DGCs was increased and more temporally modulated by the neocortical SWO. We conclude that UP/DOWN state dynamics dominate the V m of DGCs and firing early during epileptogenesis. This abnormally strong neocortical influence on the dynamics of DGCs may profoundly modify the hippocampus-neocortex dialogue during sleep and associated cognitive functions.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U901, 13273 Marseille, France; Unité Mixte de Recherche 901, Aix-Marseille University, 13273 Marseille, France; Institut de neurobiologie de la méditerranée, 13273 Marseille, France.
authors.forename: David W
authors.initials: DW
authors.lastname: Ouedraogo
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U901, 13273 Marseille, France; Unité Mixte de Recherche 901, Aix-Marseille University, 13273 Marseille, France; Institut de neurobiologie de la méditerranée, 13273 Marseille, France; Department of Neurological Sciences, University of Vermont, Burlington, Vermont 05405.
authors.forename: Pierre-Pascal
authors.initials: PP
authors.lastname: Lenck-Santini
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U901, 13273 Marseille, France; Unité Mixte de Recherche 901, Aix-Marseille University, 13273 Marseille, France; Institut de neurobiologie de la méditerranée, 13273 Marseille, France; Centre National de la Recherche Scientifique, Institut des Sciences du Mouvement, Unité Mixte de Recherche 7287, Aix-Marseille University, 13288 Marseille, France.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Marti
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U901, 13273 Marseille, France; Unité Mixte de Recherche 901, Aix-Marseille University, 13273 Marseille, France; Institut de neurobiologie de la méditerranée, 13273 Marseille, France.
authors.forename: David
authors.initials: D
authors.lastname: Robbe
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U901, 13273 Marseille, France; Unité Mixte de Recherche 901, Aix-Marseille University, 13273 Marseille, France; Institut de neurobiologie de la méditerranée, 13273 Marseille, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Crépel
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U901, 13273 Marseille, France; Unité Mixte de Recherche 901, Aix-Marseille University, 13273 Marseille, France; Institut de neurobiologie de la méditerranée, 13273 Marseille, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Epsztein
mesh_terms: D000818:Animals; D018891:Dentate Gyrus / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000503:physiopathology*; D018020:Lithium Compounds; D008297:Male; D008564:Membrane Potentials / Q000502:physiology*; D008839:Microelectrodes; D019579:Neocortex / Q000473:pathology / Q000503:physiopathology*; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009474:Neurons / Q000473:pathology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010507:Periodicity; D010862:Pilocarpine; D017208:Rats, Wistar
chemical_list: D018020:Lithium Compounds; D010862:Pilocarpine
keywords: UP/DOWN state; dentate gyrus; epilepsy; in vivo whole-cell recordings; sleep; slow oscillation