title: The effect of amygdala kindling on neuronal firing patterns in the lateral thalamus in the GAERS model of absence epilepsy.
abstract: OBJECTIVE
  The co-occurrence of absence and mesial temporal lobe epilepsy is rare in both humans and animal models. Consistent with this, rat models of absence epilepsy, including genetic absence epilepsy rats from Strasbourg (GAERS), are resistant to experimental temporal lobe epileptogenesis, in particular by amygdala kindling. Structures within the cortical-thalamocortical system are critically involved in the generation and maintenance of the electrographic spike-and-wave discharges (SWDs) that characterize absence seizures. Using in vivo electrophysiologic recordings, this study investigated the role of thalamocortical circuitry in the generalization of amygdala-kindling induced seizures in the GAERS and the nonepileptic control (NEC) strain of Wistar rats.
  
  
  METHODS
  GAERS and NEC rats were implanted with a stimulating electrode in amygdala and stimulated at afterdischarge threshold twice daily to a maximum number of 30 stimulations. Thereafter extracellular single neuron recordings were performed in vivo under neuroleptanesthesia in the thalamocortical network.
  
  
  RESULTS
  In NEC rats, amygdala kindling induced convulsive class V seizures and altered characteristics of neuronal activity in the thalamic reticular nucleus (TRN), in particular decreased firing rates and increased burst firing patterns. Less marked changes were seen in other regions examined: the ventroposteromedial nucleus of thalamus (VPM), the CA3 region of the hippocampus, and the deep layers (V/VI) of the cortex. GAERS did not progress beyond class II seizures, with a matched number of kindling stimulations, and the thalamic neuronal firing alterations observed in NEC rats were not seen.
  
  
  CONCLUSIONS
  These data suggest that the TRN plays an important role in kindling resistance in GAERS and is central to the control of secondary generalization of limbic seizures.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey.
authors.forename: Nihan
authors.initials: N
authors.lastname: Çarçak
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zheng
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Idrish
authors.initials: I
authors.lastname: Ali
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Abdullah
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.|Department of Neurology, Royal Melbourne Hospital, Melbourne, Vic., Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: French
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Powell
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Nigel C
authors.initials: NC
authors.lastname: Jones
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Leena
authors.initials: L
authors.lastname: van Raay
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Gil
authors.initials: G
authors.lastname: Rind
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, Marmara University School of Medicine, Istanbul, Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Onat
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Vic., Australia.|Department of Neurology, Royal Melbourne Hospital, Melbourne, Vic., Australia.
authors.forename: Terence J
authors.initials: TJ
authors.lastname: O'Brien
mesh_terms: D000679:Amygdala / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D056654:CA3 Region, Hippocampal / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D004833:Epilepsy, Temporal Lobe / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D007696:Kindling, Neurologic / Q000502:physiology*; D020647:Lateral Thalamic Nuclei / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000235:genetics* / Q000502:physiology*
keywords: Absence epilepsy; Amygdala kindling; In vivo juxtacellular single unit recordings; Mesial temporal lobe epilepsy; Ventrobasal thalamic nucleus