Emília Tóth1, Virág Bokodi2, Zoltán Somogyvári3, Zsófia Maglóczky4, Lucia Wittner5, István Ulbert5, Loránd Erőss6, Dániel Fabó7. 1. Epilepsy Centrum, Dept of Neurology, National Institute of Clinical Neurosciences, Budapest, 1145, Hungary; Department of Neurology, The University of Texas Health Science Center at Houston, Houston, Texas, 77030, USA (present affiliation). 2. Epilepsy Centrum, Dept of Neurology, National Institute of Clinical Neurosciences, Budapest, 1145, Hungary; Pázmány Péter Catholic University, Faculty of Information Technology and Bionics, Budapest, 1083, Hungary. 3. Department of Computational Sciences, Wigner Research Centre, Eötvös Loránd Research Network, Budapest, 1121, Hungary. 4. Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Eötvös Loránd Research Network, Budapest, 1083, Hungary; Human Brain Research Laboratory, Institute of Experimental Medicine, Eötvös Loránd Research Network, Budapest, 1083, Hungary. 5. Epilepsy Centrum, Dept of Neurology, National Institute of Clinical Neurosciences, Budapest, 1145, Hungary; Pázmány Péter Catholic University, Faculty of Information Technology and Bionics, Budapest, 1083, Hungary; Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Eötvös Loránd Research Network, Budapest, 1117, Hungary. 6. Pázmány Péter Catholic University, Faculty of Information Technology and Bionics, Budapest, 1083, Hungary; Department of Functional Neurosurgery, National Institute of Clinical Neurosciences, Budapest, 1145, Hungary. 7. Epilepsy Centrum, Dept of Neurology, National Institute of Clinical Neurosciences, Budapest, 1145, Hungary. Electronic address: fabo.daniel@gmail.com.
Abstract
OBJECTIVE: The goal of this study was to define the pathology and anesthesia dependency of single pulse electrical stimulation (SPES) dependent high-frequency oscillations (HFOs, ripples, fast ripples) in the hippocampal formation. METHODS: Laminar profile of electrically evoked short latency (<100 ms) high-frequency oscillations (80-500 Hz) was examined in the hippocampus of therapy-resistant epileptic patients (6 female, 2 male) in vivo, under general anesthesia. RESULTS: Parahippocampal SPES evoked HFOs in all recorded hippocampal subregions (Cornu Ammonis 2-3, dentate gyrus, and subiculum) were not uniform, rather the combination of ripples, fast ripples, sharp transients, and multiple unit activities. Mild and severe hippocampal sclerosis (HS) differed in the probability to evoke fast ripples: it decreased with the severity of sclerosis in CA2-3 but increased in the subiculum. Modulation in the ripple spectrum was observed only in the subiculum with increased fast HFO rate and frequency in severe HS. Inhalational anesthetics (isoflurane) suppressed the chance to evoke HFOs compared to propofol. CONCLUSION: The presence of early HFOs in the dentate gyrus and early fast HFOs (>250 Hz) in the other subregions indicate the pathological nature of these evoked oscillations. Subiculum was found to be active producing HFOs in parallel with the cell loss in the hippocampus proper, which emphasize the role of this region in the generation of epileptic activity.
OBJECTIVE: The goal of this study was to define the pathology and anesthesia dependency of single pulse electrical stimulation (SPES) dependent high-frequency oscillations (HFOs, ripples, fast ripples) in the hippocampal formation. METHODS: Laminar profile of electrically evoked short latency (<100 ms) high-frequency oscillations (80-500 Hz) was examined in the hippocampus of therapy-resistant epileptic patients (6 female, 2 male) in vivo, under general anesthesia. RESULTS: Parahippocampal SPES evoked HFOs in all recorded hippocampal subregions (Cornu Ammonis 2-3, dentate gyrus, and subiculum) were not uniform, rather the combination of ripples, fast ripples, sharp transients, and multiple unit activities. Mild and severe hippocampal sclerosis (HS) differed in the probability to evoke fast ripples: it decreased with the severity of sclerosis in CA2-3 but increased in the subiculum. Modulation in the ripple spectrum was observed only in the subiculum with increased fast HFO rate and frequency in severe HS. Inhalational anesthetics (isoflurane) suppressed the chance to evoke HFOs compared to propofol. CONCLUSION: The presence of early HFOs in the dentate gyrus and early fast HFOs (>250 Hz) in the other subregions indicate the pathological nature of these evoked oscillations. Subiculum was found to be active producing HFOs in parallel with the cell loss in the hippocampus proper, which emphasize the role of this region in the generation of epileptic activity.
Authors: William E Skaggs; Bruce L McNaughton; Michele Permenter; Matthew Archibeque; Julie Vogt; David G Amaral; Carol A Barnes Journal: J Neurophysiol Date: 2007-05-23 Impact factor: 2.714
Authors: Julia Jacobs; Pierre Levan; Claude-Edouard Châtillon; André Olivier; François Dubeau; Jean Gotman Journal: Brain Date: 2009-03-18 Impact factor: 13.501
Authors: Julia Jacobs; Pierre LeVan; Rahul Chander; Jeffery Hall; François Dubeau; Jean Gotman Journal: Epilepsia Date: 2008-05-09 Impact factor: 5.864
Authors: Catalina Alvarado-Rojas; Gilles Huberfeld; Michel Baulac; Stéphane Clemenceau; Stéphane Charpier; Richard Miles; Liset Menendez de la Prida; Michel Le Van Quyen Journal: Ann Neurol Date: 2014-12-19 Impact factor: 10.422