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Song H, Mah B, Sun Y, Aloysius N, Bai Y, Zhang L. Development of spontaneous recurrent seizures accompanied with increased rates of interictal spikes and decreased hippocampal delta and theta activities following extended kindling in mice. Exp Neurol 2024; 379:114860. [PMID: 38876195 DOI: 10.1016/j.expneurol.2024.114860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/30/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024]
Abstract
Interictal epileptiform discharges refer to aberrant brain electrographic signals between seizures and feature intermittent interictal spikes (ISs), sharp waves, and/or abnormal rhythms. Recognition of these epileptiform activities by electroencephalographic (EEG) examinations greatly aids epilepsy diagnosis and localization of the seizure onset zone. ISs are a major form of interictal epileptiform discharges recognized in animal models of epilepsy. Progressive changes in IS waveforms, IS rates, and/or associated fast ripple oscillations have been shown to precede the development of spontaneous recurrent seizures (SRS) in various animal models. IS expressions in the kindling model of epilepsy have been demonstrated but IS changes during the course of SRS development in extended kindled animals remain to be detailed. We hence addressed this issue using a mouse model of kindling-induced SRS. Adult C57 black mice received twice daily hippocampal stimulations until SRS occurrence, with 24-h EEG monitoring performed following 50, 80, and ≥ 100 stimulations and after observation of SRS. In the stimulated hippocampus, increases in spontaneous ISs rates, but not in IS waveforms nor IS-associated fast ripples, along with decreased frequencies of hippocampal delta and theta rhythms, were observed before SRS onset. Comparable increases in IS rates were further observed in the unstimulated hippocampus, piriform cortex, and entorhinal cortex, but not in the unstimulated parietal cortex and dorsomedial thalamus. These data provide original evidence suggesting that increases in hippocampal IS rates, together with reductions in hippocampal delta and theta rhythms are closely associated with development of SRS in a rodent kindling model.
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Affiliation(s)
- Hongmei Song
- Departments of Neurosurgery, India; Krembil Research Institute, University Health Network, Canada.
| | - Bryan Mah
- Krembil Research Institute, University Health Network, Canada
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Canada
| | - Nancy Aloysius
- Krembil Research Institute, University Health Network, Canada
| | - Yang Bai
- Neuro-Oncology the First Hospital of Jilin University, China.
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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2
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Vahedipour A, Short MR, Timnak A, Maghsoudi OH, Hallowell T, Gerstenhaber J, Cappellari O, Lemay M, Spence AJ. A versatile system for neuromuscular stimulation and recording in the mouse model using a lightweight magnetically coupled headmount. J Neurosci Methods 2021; 362:109319. [PMID: 34400212 DOI: 10.1016/j.jneumeth.2021.109319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 11/26/2022]
Abstract
Neural stimulation and recording in rodents are common methods to better understand the nervous system and improve the quality of life of individuals who are suffering from neurological disorders (e.g., epilepsy), as well as for permanent reduction of chronic pain in patients with neuropathic pain and spinal-cord injury. This method requires a neural interface (e.g., a headmount) to couple the implanted neural device with instrumentation system. The size and the total weight of such headmounts should be designed in a way to minimize its effect on the movement of the animal. This is a crucial factor in gait, kinematic, and behavioral neuroscience studies of freely moving mice. Here we introduce a lightweight 'snap-in' electro-magnetic headmount that is extremely small, and uses strong neodymium magnetics to enable a reliable connection without sacrificing the lightweight of the device. Additionally, the headmount requires minimal surgical intervention during the implantation, resulting in minimal tissue damage. The device has demonstrated itself to be robust, and successfully provided direct electrical stimulation of nerve and electrical muscle stimulation and recording, as well as powering implanted LEDs for optogenetic use scenarios.
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Affiliation(s)
- Annie Vahedipour
- Department of Pediatrics, Neurology, Yale University, New Haven, CT 06510, USA.
| | - Matthew R Short
- Functional and Applied Biomechanics Section, Rehabilitation Medicine Department, National Institutes of Health, Bethesda, MD 20814, USA
| | - Azadeh Timnak
- Laboratory for Cell and Medicine, School of Medicine, Stanford University, Palo Alto, CA 94304, USA
| | - Omid Haji Maghsoudi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Thomas Hallowell
- Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | | | - Ornella Cappellari
- Department of Pharmacy-Drug Science, University of Bari "Aldo Moro", 70125 Bari, Italy
| | - Michel Lemay
- Department of Bioengineering, Temple University, Philadelphia, PA 19122, USA
| | - Andrew J Spence
- Department of Bioengineering, Temple University, Philadelphia, PA 19122, USA
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3
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Liu H, Tufa U, Zahra A, Chow J, Sivanenthiran N, Cheng C, Liu Y, Cheung P, Lim S, Jin Y, Mao M, Sun Y, Wu C, Wennberg R, Bardakjian B, Carlen PL, Eubanks JH, Song H, Zhang L. Electrographic Features of Spontaneous Recurrent Seizures in a Mouse Model of Extended Hippocampal Kindling. Cereb Cortex Commun 2021; 2:tgab004. [PMID: 34296153 PMCID: PMC8152854 DOI: 10.1093/texcom/tgab004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/08/2021] [Accepted: 01/13/2021] [Indexed: 01/14/2023] Open
Abstract
Epilepsy is a chronic neurological disorder characterized by spontaneous recurrent seizures (SRS) and comorbidities. Kindling through repetitive brief stimulation of a limbic structure is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling over a period up to a few months can induce SRS, which may simulate slowly evolving epileptogenesis of temporal lobe epilepsy. Currently, electroencephalographic (EEG) features of SRS in rodent models of extended kindling remain to be detailed. We explored this using a mouse model of extended hippocampal kindling. Intracranial EEG recordings were made from the kindled hippocampus and unstimulated hippocampal, neocortical, piriform, entorhinal, or thalamic area in individual mice. Spontaneous EEG discharges with concurrent low-voltage fast onsets were observed from the two corresponding areas in nearly all SRS detected, irrespective of associated motor seizures. Examined in brain slices, epileptiform discharges were induced by alkaline artificial cerebrospinal fluid in the hippocampal CA3, piriform and entorhinal cortical areas of extended kindled mice but not control mice. Together, these in vivo and in vitro observations suggest that the epileptic activity involving a macroscopic network may generate concurrent discharges in forebrain areas and initiate SRS in hippocampally kindled mice.
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Affiliation(s)
- Haiyu Liu
- Departments of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021 China.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Uilki Tufa
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3H5, Canada
| | - Anya Zahra
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Jonathan Chow
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Nila Sivanenthiran
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Chloe Cheng
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yapg Liu
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Phinehas Cheung
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yaozhong Jin
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Min Mao
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Richard Wennberg
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada
| | - Berj Bardakjian
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3H5, Canada
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James H Eubanks
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Surgery, University of Toronto, Toronto, Ontario M5G 1X5, Canada
| | - Hongmei Song
- Departments of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021 China.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada
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Fedor FZ, Zátonyi A, Cserpán D, Somogyvári Z, Borhegyi Z, Juhász G, Fekete Z. Application of a flexible polymer microECoG array to map functional coherence in schizophrenia model. MethodsX 2020; 7:101117. [PMID: 33194564 PMCID: PMC7644754 DOI: 10.1016/j.mex.2020.101117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 10/19/2020] [Indexed: 02/03/2023] Open
Abstract
Anatomically, connections form the fundamental brain network, functionally the different types of oscillatory electric activities are creating a temporarily connected fraction of the anatomical connectome generating an output to the motor system. Schizophrenia can be considered as a connectome disease, in which the sensory input generates a schizophrenia specific temporary connectome and the signal processing becomes diseased showing hallucinations and adverse behavioral reactions. In this work, flexible, 32-channel polymer microelectrode arrays fabricated by the authors are used to map the functional coherence on large cortical areas during physiological activities in a schizophrenia model in rats.-Fabrication of a flexible microECoG array is shown.-Protocol to use a flexible microECoG is demonstrated to characterize connectome diseases in rats.-Customized method to analyze the functional coherence between different cortical areas during visually evoked potential is detailed.-R-based implementation of the analysis method is presented.
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Affiliation(s)
- F Z Fedor
- Doctoral School of Chemical Engineering and Material Sciences, Pannon University, Veszprém, Hungary.,ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, Hungary.,Research Group for Implantable Microsystems, Faculty of Information Technology & Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - A Zátonyi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, Hungary.,Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary.,Research Group for Implantable Microsystems, Faculty of Information Technology & Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - D Cserpán
- Theoretical Neuroscience and Complex Systems Research Group, Department of Computational Sciences, Wigner Research Centre for Physics, Budapest, Hungary
| | - Z Somogyvári
- Theoretical Neuroscience and Complex Systems Research Group, Department of Computational Sciences, Wigner Research Centre for Physics, Budapest, Hungary
| | - Z Borhegyi
- Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - G Juhász
- Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - Z Fekete
- Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary.,Research Group for Implantable Microsystems, Faculty of Information Technology & Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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Aquilino MS, Whyte-Fagundes P, Lukewich MK, Zhang L, Bardakjian BL, Zoidl GR, Carlen PL. Pannexin-1 Deficiency Decreases Epileptic Activity in Mice. Int J Mol Sci 2020; 21:ijms21207510. [PMID: 33053775 PMCID: PMC7589538 DOI: 10.3390/ijms21207510] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023] Open
Abstract
Objective: Pannexin-1 (Panx1) is suspected of having a critical role in modulating neuronal excitability and acute neurological insults. Herein, we assess the changes in behavioral and electrophysiological markers of excitability associated with Panx1 via three distinct models of epilepsy. Methods Control and Panx1 knockout C57Bl/6 mice of both sexes were monitored for their behavioral and electrographic responses to seizure-generating stimuli in three epilepsy models—(1) systemic injection of pentylenetetrazol, (2) acute electrical kindling of the hippocampus and (3) neocortical slice exposure to 4-aminopyridine. Phase-amplitude cross-frequency coupling was used to assess changes in an epileptogenic state resulting from Panx1 deletion. Results: Seizure activity was suppressed in Panx1 knockouts and by application of Panx1 channel blockers, Brilliant Blue-FCF and probenecid, across all epilepsy models. In response to pentylenetetrazol, WT mice spent a greater proportion of time experiencing severe (stage 6) seizures as compared to Panx1-deficient mice. Following electrical stimulation of the hippocampal CA3 region, Panx1 knockouts had significantly shorter evoked afterdischarges and were resistant to kindling. In response to 4-aminopyridine, neocortical field recordings in slices of Panx1 knockout mice showed reduced instances of electrographic seizure-like events. Cross-frequency coupling analysis of these field potentials highlighted a reduced coupling of excitatory delta–gamma and delta-HF rhythms in the Panx1 knockout. Significance: These results suggest that Panx1 plays a pivotal role in maintaining neuronal hyperexcitability in epilepsy models and that genetic or pharmacological targeting of Panx1 has anti-convulsant effects.
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Affiliation(s)
- Mark S. Aquilino
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
- Correspondence:
| | - Paige Whyte-Fagundes
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M5S 3G9, Canada; (P.W.-F.); (G.R.Z.)
| | - Mark K. Lukewich
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
| | - Liang Zhang
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
| | - Berj L. Bardakjian
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
| | - Georg R. Zoidl
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M5S 3G9, Canada; (P.W.-F.); (G.R.Z.)
| | - Peter L. Carlen
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
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6
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Sabetghadam A, Wu C, Liu J, Zhang L, Reid AY. Increased epileptogenicity in a mouse model of neurofibromatosis type 1. Exp Neurol 2020; 331:113373. [PMID: 32502580 DOI: 10.1016/j.expneurol.2020.113373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 11/19/2022]
Abstract
RATIONALE Neurofibromatosis type 1 (NF1) is associated with higher rates of epilepsy compared to the general population. Some NF1 patients with epilepsy do not have intracranial lesions, suggesting the genetic mutation itself may contribute to higher rates of epilepsy in these patients. We have recently demonstrated increased seizure susceptibility in the Nf1+/- mouse, but it is unknown whether this model displays altered epileptogenicity, as has been reported in patients with NF1. The aim of this study was to determine whether the Nf1+/- mouse is more susceptible to electrical kindling-induced epileptogenesis. METHODS Young male or female adult Nf1+/- or Nf1+/+ (wild-type; WT) mice were implanted with electrodes for neocortical or hippocampal kindling paradigms. Neocortical kindling was performed for 40 stimulation sessions followed by baseline EEG monitoring to detect possible SRSs. Hippocampal kindling was performed with a modified extended kindling paradigm, completed to a maximum of 80 sessions to try to induce spontaneous repetitive seizures (SRSs). Western blot assays were performed in naïve and kindled mice to compare levels of Akt and MAPK (ERK1/2), proteins downstream of the NF1 mutation. RESULTS The average initial neocortical after-discharge threshold (ADT) was significantly lower in the Nf1+/- group, which also required fewer stimulations to reach stage 5 seizure, had greater average seizure severity across all kindling sessions, had a greater number of convulsive seizures, and had a faster progression of after-discharge duration and Racine score during kindling. No WT mice exhibited SRS after neocortical kindling, versus 33% of Nf1+/- mice. The average initial hippocampal ADT was not significantly different between the WT and Nf1+/- groups, nor was there a difference in the number of stimulations required to reach the kindled state. The WT group had a significantly higher average seizure severity across all kindling sessions as compared with the Nf1+/- mice. The WT group also had faster progression of the Racine seizure score over the kindling sessions, mainly due to a faster increase in seizures severity early during the kindling process. However, SRSs were seen in 50% of Nf1+/- mice after modified extended kindling and in no WT mice. Western blots showed hippocampal kindling increased the ratio of phosphorylated/total Akt in both the WT and Nf1+/- mice, while neocortical kindling led to increased ratios of phosphorylated/total Akt and MAPK in Nf1+/- mice only. CONCLUSIONS We have demonstrated for the first time an increased rate of epileptogenesis in an animal model of NF1 with no known macroscopic/neoplastic brain lesions. This work provides evidence for the genetic mutation itself playing a role in seizures and epilepsy in patients with NF1, and supports the use of the Nf1+/- mouse model in future mechanistic studies.
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Affiliation(s)
- A Sabetghadam
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada.
| | - C Wu
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - J Liu
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - L Zhang
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
| | - A Y Reid
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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7
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Fomicheva A, Zhou C, Sun QQ, Gomelsky M. Engineering Adenylate Cyclase Activated by Near-Infrared Window Light for Mammalian Optogenetic Applications. ACS Synth Biol 2019; 8:1314-1324. [PMID: 31145854 DOI: 10.1021/acssynbio.8b00528] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Light in the near-infrared optical window (NIRW) penetrates deep through mammalian tissues, including the skull and brain tissue. Here we engineered an adenylate cyclase (AC) activated by NIRW light (NIRW-AC) and suitable for mammalian applications. To accomplish this goal, we constructed fusions of several bacteriophytochrome photosensory and bacterial AC modules using guidelines for designing chimeric homodimeric bacteriophytochromes. One engineered NIRW-AC, designated IlaM5, has significantly higher activity at 37 °C, is better expressed in mammalian cells, and can mediate cAMP-dependent photoactivation of gene expression in mammalian cells, in favorable contrast to the NIRW-ACs engineered earlier. The ilaM5 gene expressed from an AAV vector was delivered into the ventral basal thalamus region of the mouse brain, resulting in the light-controlled suppression of the cAMP-dependent wave pattern of the sleeping brain known as spindle oscillations. Reversible spindle oscillation suppression was observed in sleeping mice exposed to light from an external light source. This study confirms the robustness of principles of homodimeric bacteriophytochrome engineering, describes a NIRW-AC suitable for mammalian optogenetic applications, and demonstrates the feasibility of controlling brain activity via NIRW-ACs using transcranial irradiation.
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Affiliation(s)
- Anastasia Fomicheva
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Chen Zhou
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Mark Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, United States
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8
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Williams AJ, Sun QQ. Cortical Layer and Spectrotemporal Architecture of Epileptiform Activity in vivo in a Mouse Model of Focal Cortical Malformation. Front Neural Circuits 2019; 13:2. [PMID: 30723398 PMCID: PMC6349724 DOI: 10.3389/fncir.2019.00002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022] Open
Abstract
Our objective is to examine the layer and spectrotemporal architecture and laminar distribution of high-frequency oscillations (HFOs) in a neonatal freeze lesion model of focal cortical dysplasia (FCD) associated with a high prevalence of spontaneous spike-wave discharges (SWDs). Electrophysiological recording of local field potentials (LFPs) in control and freeze lesion animals were obtained with linear micro-electrode arrays to detect presence of HFOs as compared to changes in spectral power, signal coherence, and single-unit distributions during "hyper-excitable" epochs of anesthesia-induced burst-suppression (B-S). Result were compared to HFOs observed during spontaneous SWDs in animals during sleep. Micro-electrode array recordings from the malformed cortex indicated significant increases in the presence of HFOs above 100 Hz and associated increases in spectral power and altered LFP coherence of recorded signals across cortical lamina of freeze-lesioned animals with spontaneous bursts of high-frequency activity, confined predominately to granular and supragranular layers. Spike sorting of well-isolated single-units recorded from freeze-lesioned cortex indicated an increase in putative excitatory cell activity in the outer cortical layers that showed only a weak association with HFOs while deeper inhibitory units were strongly phase-locked to high-frequency ripple (HFR) oscillations (300-800 Hz). Both SWDs and B-S show increases in HFR activity that were phase-locked to the high-frequency spike pattern occurring at the trough of low frequency oscillations. The spontaneous cyclic spiking of cortical inhibitory cells appears to be the driving substrate behind the HFO patterns associated with SWDs and a hyperexcitable supragranular layer near the malformed cortex may play a key role in epileptogenesis in our model. These data, derived from a mouse model with a distinct focal cortical malformation, support recent clinical data that HFOs, particularly fast ripples, is a biomarker to help define the cortical seizure zone, and provide limited insights toward understanding cellular level changes underlying the HFOs.
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Affiliation(s)
- Anthony J Williams
- Department of Zoology & Physiology, University of Wyoming, Laramie, WY, United States
| | - Qian-Quan Sun
- Department of Zoology & Physiology, University of Wyoming, Laramie, WY, United States
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9
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Wither RG, Colic S, Bardakjian BL, Snead OC, Zhang L, Eubanks JH. Electrographic and pharmacological characterization of a progressive epilepsy phenotype in female MeCP2-deficient mice. Epilepsy Res 2018; 140:177-183. [PMID: 29414525 DOI: 10.1016/j.eplepsyres.2018.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 11/27/2022]
Abstract
Rett Syndrome is a neurodevelopmental disorder caused primarily by mutations in the gene encoding Methyl-CpG-binding protein 2 (MECP2). Spontaneous epileptiform activity is a common co-morbidity present in Rett syndrome, and hyper-excitable neural networks are present in MeCP2-deficient mouse models of Rett syndrome. In this study we conducted a longitudinal assessment of spontaneous cortical electrographic discharges in female MeCP2-deficient mice and defined the pharmacological responsiveness of these discharges to anti-convulsant drugs. Our data show that cortical discharge activity in female MeCP2-deficient mice progressively increases in severity as the mice age, with discharges being more frequent and of longer durations at 19-24 months of age compared to 3 months of age. Semiologically and pharmacologically, this basal discharge activity in female MeCP2-deficient mice displayed electroclinical properties consistent with absence epilepsy. Only rarely were convulsive seizures observed in these mice at any age. Since absence epilepsy is infrequently observed in Rett syndrome patients, these results indicate that the predominant spontaneous electroclinical phenotype of MeCP2-deficient mice we examined does not faithfully recapitulate the most prevalent seizure types observed in affected patients.
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Affiliation(s)
- Robert G Wither
- Division of Genetics and Development, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada; Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Sinisa Colic
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Berj L Bardakjian
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - O Carter Snead
- Department of Medicine (Neurology), University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Liang Zhang
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada; University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James H Eubanks
- Division of Genetics and Development, Krembil Research Institute, University Health Network, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada; University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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10
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Yeon C, Kim D, Kim K, Chung E. Visual Evoked Potential Recordings in Mice Using a Dry Non-invasive Multi-channel Scalp EEG Sensor. J Vis Exp 2018. [PMID: 29364268 DOI: 10.3791/56927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
For scalp EEG research environments with laboratory mice, we designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable because of the plunger-spring-barrel structural facet and mechanical strengths resulting from metal materials. The whole process for acquiring the VEP responses in vivo from a mouse consists of four steps: (1) sensor assembly, (2) animal preparation, (3) VEP measurement, and (4) signal processing. This paper presents representative measurements of VEP responses from multiple mice with a submicro-voltage signal resolution and sub-hundred millisecond temporal resolution. Although the proposed method is safer and more convenient compared to other previously reported animal EEG acquiring methods, there are remaining issues including how to enhance the signal-to-noise ratio and how to apply this technique with freely moving animals. The proposed method utilizes easily available resources and shows a repetitive VEP response with a satisfactory signal quality. Therefore, this method could be utilized for longitudinal experimental studies and reliable translational research exploiting non-invasive paradigms.
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Affiliation(s)
- Chanmi Yeon
- Department of Biomedical Science and Engineering (BMSE), Gwangju Institute of Science and Technology (GIST)
| | - Donghyeon Kim
- School of Electrical Engineering and Computer Science (EECS), Gwangju Institute of Science and Technology (GIST)
| | - Kiseon Kim
- School of Electrical Engineering and Computer Science (EECS), Gwangju Institute of Science and Technology (GIST)
| | - Euiheon Chung
- Department of Biomedical Science and Engineering (BMSE), Gwangju Institute of Science and Technology (GIST); School of Mechanical Engineering (SME), Gwangju Institute of Science and Technology (GIST);
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11
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Stover KR, Lim S, Zhou TL, Stafford PM, Chow J, Li H, Sivanenthiran N, Mylvaganam S, Wu C, Weaver DF, Eubanks J, Zhang L. Susceptibility to hippocampal kindling seizures is increased in aging C57 black mice. IBRO Rep 2017; 3:33-44. [PMID: 30135940 PMCID: PMC6084868 DOI: 10.1016/j.ibror.2017.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/19/2017] [Accepted: 08/20/2017] [Indexed: 11/23/2022] Open
Abstract
The incidence of seizures increases with old age. Stroke, dementia and brain tumors are recognized risk factors for new-onset seizures in the aging populations and the incidence of these conditions also increased with age. Whether aging is associated with higher seizure susceptibility in the absence of the above pathologies remains unclear. We used classic kindling to explore this issue as the kindling model is highly reproducible and allows close monitoring of electrographic and motor seizure activities in individual animals. We kindled male young and aging mice (C57BL/6 strain, 2-3 and 18-22 months of age) via daily hippocampal CA3 stimulation and monitored seizure activity via video and electroencephalographic recordings. The aging mice needed fewer stimuli to evoke stage-5 motor seizures and exhibited longer hippocampal afterdischarges and more frequent hippocampal spikes relative to the young mice, but afterdischarge thresholds and cumulative afterdischarge durations to stage 5 motor seizures were not different between the two age groups. While hippocampal injury and structural alterations at cellular and micro-circuitry levels remain to be examined in the kindled mice, our present observations suggest that susceptibility to hippocampal CA3 kindling seizures is increased with aging in male C57 black mice.
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Affiliation(s)
- Kurt R. Stover
- Krembil Research Institute, University Health Network, Canada
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Canada
| | - Terri-Lin Zhou
- Krembil Research Institute, University Health Network, Canada
| | | | - Jonathan Chow
- Krembil Research Institute, University Health Network, Canada
| | - Haoyuan Li
- Krembil Research Institute, University Health Network, Canada
| | | | | | - Chiping Wu
- Krembil Research Institute, University Health Network, Canada
| | - Donald F. Weaver
- Krembil Research Institute, University Health Network, Canada
- Departments of Chemistry, University of Toronto, Canada
- Departments of Medicine, University of Toronto, Canada
| | - James Eubanks
- Krembil Research Institute, University Health Network, Canada
- Departments of Surgery, University of Toronto, Canada
- University of Toronto Epilepsy Program, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Canada
- Departments of Medicine, University of Toronto, Canada
- University of Toronto Epilepsy Program, Canada
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12
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Bin NR, Song H, Wu C, Lau M, Sugita S, Eubanks JH, Zhang L. Continuous Monitoring via Tethered Electroencephalography of Spontaneous Recurrent Seizures in Mice. Front Behav Neurosci 2017; 11:172. [PMID: 28959196 PMCID: PMC5603658 DOI: 10.3389/fnbeh.2017.00172] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022] Open
Abstract
We describe here a simple, cost-effective apparatus for continuous tethered electroencephalographic (EEG) monitoring of spontaneous recurrent seizures in mice. We used a small, low torque slip ring as an EEG commutator, mounted the slip ring onto a standard mouse cage and connected rotary wires of the slip ring directly to animal's implanted headset. Modifications were made in the cage to allow for a convenient installation of the slip ring and accommodation of animal ambient activity. We tested the apparatus for hippocampal EEG recordings in adult C57 black mice. Spontaneous recurrent seizures were induced using extended hippocampal kindling (≥95 daily stimulation). Control animals underwent similar hippocampal electrode implantations but no stimulations were given. Combined EEG and webcam monitoring were performed for 24 h daily for 5–9 consecutive days. During the monitoring periods, the animals moved and accessed water and food freely and showed no apparent restriction in ambient cage activities. Ictal-like hippocampal EEG discharges and concurrent convulsive behaviors that are characteristics of spontaneous recurrent seizures were reliably recorded in a majority of the monitoring experiments in extendedly kindled but not in control animals. However, 1–2 rotary wires were disconnected from the implanted headset in some animals after continuous recordings for ≥5 days. The key features and main limitations of our recording apparatus are discussed.
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Affiliation(s)
- Na-Ryum Bin
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada
| | - Hongmei Song
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Neurosurgery, The First Hospital of Jilin UniversityJilin, China
| | - Chiping Wu
- Krembil Research Institute, University Health NetworkToronto, ON, Canada
| | - Marcus Lau
- Krembil Research Institute, University Health NetworkToronto, ON, Canada
| | - Shuzo Sugita
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada
| | - James H Eubanks
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada.,Division of Neurosurgery, Department of Surgery, University of TorontoToronto, ON, Canada.,The Epilepsy Research Program of Ontario Brain InstituteToronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,The Epilepsy Research Program of Ontario Brain InstituteToronto, ON, Canada.,Division of Neurology, Department of Medicine, University of TorontoToronto, ON, Canada
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13
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Kim D, Yeon C, Kim K. Development and Experimental Validation of a Dry Non-Invasive Multi-Channel Mouse Scalp EEG Sensor through Visual Evoked Potential Recordings. SENSORS 2017; 17:s17020326. [PMID: 28208777 PMCID: PMC5335932 DOI: 10.3390/s17020326] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/30/2016] [Accepted: 02/04/2017] [Indexed: 11/16/2022]
Abstract
In this paper, we introduce a dry non-invasive multi-channel sensor for measuring brainwaves on the scalps of mice. The research on laboratory animals provide insights to various practical applications involving human beings and other animals such as working animals, pets, and livestock. An experimental framework targeting the laboratory animals has the potential to lead to successful translational research when it closely resembles the environment of real applications. To serve scalp electroencephalography (EEG) research environments for the laboratory mice, the dry non-invasive scalp EEG sensor with sixteen electrodes is proposed to measure brainwaves over the entire brain area without any surgical procedures. We validated the proposed sensor system with visual evoked potential (VEP) experiments elicited by flash stimulations. The VEP responses obtained from experiments are compared with the existing literature, and analyzed in temporal and spatial perspectives. We further interpret the experimental results using time-frequency distribution (TFD) and distance measurements. The developed sensor guarantees stable operations for in vivo experiments in a non-invasive manner without surgical procedures, therefore exhibiting a high potential to strengthen longitudinal experimental studies and reliable translational research exploiting non-invasive paradigms.
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Affiliation(s)
- Donghyeon Kim
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.
| | - Chanmi Yeon
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.
| | - Kiseon Kim
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.
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14
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Kuwabara M, Tashiro H, Terasawa Y, Osawa K, Tokuda T, Ohta J, Fujikado T. Development of Chronic Implantable Electrodes for Long-term Visual Evoked Potential Recording in Rabbits. ADVANCED BIOMEDICAL ENGINEERING 2017. [DOI: 10.14326/abe.6.59] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Mariko Kuwabara
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University
| | - Hiroyuki Tashiro
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University
- Graduate School of Materials Science, Nara Institute of Science & Technology
| | - Yasuo Terasawa
- Vision Institute, Nidek Co., Ltd
- Graduate School of Materials Science, Nara Institute of Science & Technology
| | | | - Takashi Tokuda
- Graduate School of Materials Science, Nara Institute of Science & Technology
| | - Jun Ohta
- Graduate School of Materials Science, Nara Institute of Science & Technology
| | - Takashi Fujikado
- Applied Visual Science, Osaka University Graduate School of Medicine
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15
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Chen L, Liu X, Wang H, Qu M. Gastrodin Attenuates Pentylenetetrazole-Induced Seizures by Modulating the Mitogen-Activated Protein Kinase-Associated Inflammatory Responses in Mice. Neurosci Bull 2016; 33:264-272. [PMID: 27909971 DOI: 10.1007/s12264-016-0084-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 10/14/2016] [Indexed: 01/21/2023] Open
Abstract
Gastrodin, the major component isolated from the rhizome of the Chinese traditional medicinal herb Gastrodia elata ("Tianma"), has a long history in the treatment of epilepsy and other neurological disorders. However, the molecular mechanisms are not clear. Here, we found that gastrodin ameliorated pentylenetetrazole (PTZ)-induced epileptic seizures with improvement of the electroencephalographic pattern in mice. Further studies demonstrated that gastrodin decreased the levels of the pro-inflammatory cytokines interleukin-1β and tumor necrosis factor-α while increasing interleukin-10, an anti-inflammatory cytokine in the brain. Furthermore, gastrodin attenuated the PTZ-induced microglial activation along with inhibition of mitogen-activated protein kinases, cAMP response element binding protein, and NF-κB. Our data suggest that gastrodin attenuates seizures by modulating the mitogen-activated protein kinase-associated inflammatory responses.
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Affiliation(s)
- Liming Chen
- Neurology Department, The First People's Hospital of Jingzhou, The First Affiliated Hospital of Yangtze University, Jingzhou, 434000, China
| | - Xinan Liu
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Hua Wang
- Neurology Department, The First People's Hospital of Jingzhou, The First Affiliated Hospital of Yangtze University, Jingzhou, 434000, China.
| | - Min Qu
- Hubei Provincial Key Laboratory for Applied Toxicology, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China.
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16
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Williams AJ, Zhou C, Sun QQ. Enhanced Burst-Suppression and Disruption of Local Field Potential Synchrony in a Mouse Model of Focal Cortical Dysplasia Exhibiting Spike-Wave Seizures. Front Neural Circuits 2016; 10:93. [PMID: 27891080 PMCID: PMC5102891 DOI: 10.3389/fncir.2016.00093] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/31/2016] [Indexed: 11/28/2022] Open
Abstract
Focal cortical dysplasias (FCDs) are a common cause of brain seizures and are often associated with intractable epilepsy. Here we evaluated aberrant brain neurophysiology in an in vivo mouse model of FCD induced by neonatal freeze lesions (FLs) to the right cortical hemisphere (near S1). Linear multi-electrode arrays were used to record extracellular potentials from cortical and subcortical brain regions near the FL in anesthetized mice (5–13 months old) followed by 24 h cortical electroencephalogram (EEG) recordings. Results indicated that FL animals exhibit a high prevalence of spontaneous spike-wave discharges (SWDs), predominately during sleep (EEG), and an increase in the incidence of hyper-excitable burst/suppression activity under general anesthesia (extracellular recordings, 0.5%–3.0% isoflurane). Brief periods of burst activity in the local field potential (LFP) typically presented as an arrhythmic pattern of increased theta-alpha spectral peaks (4–12 Hz) on a background of low-amplitude delta activity (1–4 Hz), were associated with an increase in spontaneous spiking of cortical neurons, and were highly synchronized in control animals across recording sites in both cortical and subcortical layers (average cross-correlation values ranging from +0.73 to +1.0) with minimal phase shift between electrodes. However, in FL animals, cortical vs. subcortical burst activity was strongly out of phase with significantly lower cross-correlation values compared to controls (average values of −0.1 to +0.5, P < 0.05 between groups). In particular, a marked reduction in the level of synchronous burst activity was observed, the closer the recording electrodes were to the malformation (Pearson’s Correlation = 0.525, P < 0.05). In a subset of FL animals (3/9), burst activity also included a spike or spike-wave pattern similar to the SWDs observed in unanesthetized animals. In summary, neonatal FLs increased the hyperexcitable pattern of burst activity induced by anesthesia and disrupted field potential synchrony between cortical and subcortical brain regions near the site of the cortical malformation. Monitoring the altered electrophysiology of burst activity under general anesthesia with multi-dimensional micro-electrode arrays may serve to define distinct neurophysiological biomarkers of epileptogenesis in human brain and improve techniques for surgical resection of epileptogenic malformed brain tissue.
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Affiliation(s)
- Anthony J Williams
- Department of Zoology and Physiology, University of Wyoming Laramie, WY, USA
| | - Chen Zhou
- Department of Zoology and Physiology, University of Wyoming Laramie, WY, USA
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming Laramie, WY, USA
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17
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Sun QQ, Zhou C, Yang W, Petrus D. Continuous spike-waves during slow-wave sleep in a mouse model of focal cortical dysplasia. Epilepsia 2016; 57:1581-1593. [PMID: 27527919 DOI: 10.1111/epi.13501] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2016] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To examine if mice with focal cortical dysplasia (FCD) develop spontaneous epileptic seizures and, if so, determine the key electroencephalography (EEG) features. METHODS Unilateral single freeze lesions to the S1 region (SFLS1R) were made in postnatal day 0-1 pups to induce a neocortical microgyrus in the right cortical hemisphere. Continuous 24-h recordings with intracranial EEG electrodes and behavioral tests were performed in adult SFLS1R and sham-control mice to assess neurologic status. RESULTS A high percentage of adult SFLS1R animals (89%, 40/45) exhibited at least one or more spontaneous nonconvulsive seizure events over the course of 24 h. Of these animals, 60% (27/45) presented with a chronic seizure state that was persistent throughout the recording session, consisting of bursts of rhythmic high-amplitude spike-wave activities and primarily occurring during periods of slow-wave sleep. In comparison, none of the control, age-matched, mice (0/12) developed seizures. The epileptic discharge pattern closely resembled a pattern of continuous spike-waves during slow-wave sleep (CSWS) of the human syndrome described as an electrical status epilepticus during slow-wave sleep (ESES). Key findings in the SFLS1R model indicated that the observed CSWS (1) were more prevalent in female (18/23) versus male (9/22, p < 0.05), (2) were strongest in the right S1 region although generalized to other brain regions, (3) were associated with significant cognitive and behavioral deficits, (4) were temporarily alleviated by ethosuximide treatment or optogenetic activation of cortical γ-aminobutyric acid (GABA)ergic neurons, and (5) theta and alpha band rhythms may play a key role in the generalization of spike-wave activities. SIGNIFICANCE This is the first report of an in vivo animal FCD model that induces chronic spontaneous electrographic brain seizures. Further characterization of the abnormal oscillations in this mouse model may lead to a better understanding of the mechanisms of CSWS/ESES.
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Affiliation(s)
- Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, U.S.A.
| | - Chen Zhou
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, U.S.A
| | - Weiguo Yang
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, U.S.A
| | - Daniel Petrus
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, U.S.A
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18
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Zhang L, Wither RG, Lang M, Wu C, Sidorova-Darmos E, Netchev H, Matolcsy CB, Snead OC, Eubanks JH. A Role for Diminished GABA Transporter Activity in the Cortical Discharge Phenotype of MeCP2-Deficient Mice. Neuropsychopharmacology 2016; 41:1467-76. [PMID: 26499511 PMCID: PMC4832024 DOI: 10.1038/npp.2015.323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/13/2015] [Accepted: 10/01/2015] [Indexed: 12/14/2022]
Abstract
Cortical network hyper-excitability is a common phenotype in mouse models lacking the transcriptional regulator methyl-CPG-binding protein 2 (MeCP2). Here, we implicate enhanced GABAB receptor activity stemming from diminished cortical expression of the GABA transporter GAT-1 in the genesis of this network hyper-excitability. We found that administering the activity-dependent GABAB receptor allosteric modulator GS-39783 to female Mecp2(+/-) mice at doses producing no effect in wild-type mice strongly potentiated their basal rates of spontaneous cortical discharge activity. Consistently, administering the GABAB receptor antagonist CGP-35348 significantly decreased basal discharge activity in these mice. Expression analysis revealed that while GABAB or extra-synaptic GABAA receptor prevalence is preserved in the MeCP2-deficient cortex, the expression of GAT-1 is significantly reduced from wild-type levels. This decrease in GAT-1 expression is consequential, as low doses of the GAT-1 inhibitor NO-711 that had no effects in wild-type mice strongly exacerbated cortical discharge activity in female Mecp2(+/-) mice. Taken together, these data indicate that the absence of MeCP2 leads to decreased cortical levels of the GAT-1 GABA transporter, which facilitates cortical network hyper-excitability in MeCP2-deficient mice by increasing the activity of cortical GABAB receptors.
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Affiliation(s)
- Liang Zhang
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Robert G Wither
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Min Lang
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Chiping Wu
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Elena Sidorova-Darmos
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Hristo Netchev
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Catherine B Matolcsy
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Orlando Carter Snead
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - James H Eubanks
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada,Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Canada,Toronto Western Hospital, 8KD-417, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada, Tel: +1 416 603 5800, ext. 2933, Fax: +1 416 603 5745, E-mail:
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19
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Wang J, Wu C, Peng J, Patel N, Huang Y, Gao X, Aljarallah S, Eubanks JH, McDonald R, Zhang L. Early-Onset Convulsive Seizures Induced by Brain Hypoxia-Ischemia in Aging Mice: Effects of Anticonvulsive Treatments. PLoS One 2015; 10:e0144113. [PMID: 26630670 PMCID: PMC4668036 DOI: 10.1371/journal.pone.0144113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 11/15/2015] [Indexed: 12/27/2022] Open
Abstract
Aging is associated with an increased risk of seizures/epilepsy. Stroke (ischemic or hemorrhagic) and cardiac arrest related brain injury are two major causative factors for seizure development in this patient population. With either etiology, seizures are a poor prognostic factor. In spite of this, the underlying pathophysiology of seizure development is not well understood. In addition, a standardized treatment regimen with anticonvulsants and outcome assessments following treatment has yet to be established for these post-ischemic seizures. Previous studies have modeled post-ischemic seizures in adult rodents, but similar studies in aging/aged animals, a group that mirrors a higher risk elderly population, remain sparse. Our study therefore aimed to investigate early-onset seizures in aging animals using a hypoxia-ischemia (HI) model. Male C57 black mice 18-20-month-old underwent a unilateral occlusion of the common carotid artery followed by a systemic hypoxic episode (8% O2 for 30 min). Early-onset seizures were detected using combined behavioral and electroencephalographic (EEG) monitoring. Brain injury was assessed histologically at different times post HI. Convulsive seizures were observed in 65% of aging mice post-HI but not in control aging mice following either sham surgery or hypoxia alone. These seizures typically occurred within hours of HI and behaviorally consisted of jumping, fast running, barrel-rolling, and/or falling (loss of the righting reflex) with limb spasms. No evident discharges during any convulsive seizures were seen on cortical-hippocampal EEG recordings. Seizure development was closely associated with acute mortality and severe brain injury on brain histological analysis. Intra-peritoneal injections of lorazepam and fosphenytoin suppressed seizures and improved survival but only when applied prior to seizure onset and not after. These findings together suggest that seizures are a major contributing factor to acute mortality in aging mice following severe brain ischemia and that early anticonvulsive treatment may prevent seizure genesis and improve overall outcomes.
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Affiliation(s)
- Justin Wang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Chiping Wu
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jessie Peng
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Nisarg Patel
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yayi Huang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxing Gao
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Salman Aljarallah
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Neurology Unit, Department of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James H. Eubanks
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario, Canada
| | - Robert McDonald
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Liang Zhang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Departments of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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20
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Opportunities for improving animal welfare in rodent models of epilepsy and seizures. J Neurosci Methods 2015; 260:2-25. [PMID: 26376175 DOI: 10.1016/j.jneumeth.2015.09.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 01/31/2023]
Abstract
Animal models of epilepsy and seizures, mostly involving mice and rats, are used to understand the pathophysiology of the different forms of epilepsy and their comorbidities, to identify biomarkers, and to discover new antiepileptic drugs and treatments for comorbidities. Such models represent an important area for application of the 3Rs (replacement, reduction and refinement of animal use). This report provides background information and recommendations aimed at minimising pain, suffering and distress in rodent models of epilepsy and seizures in order to improve animal welfare and optimise the quality of studies in this area. The report includes practical guidance on principles of choosing a model, induction procedures, in vivo recordings, perioperative care, welfare assessment, humane endpoints, social housing, environmental enrichment, reporting of studies and data sharing. In addition, some model-specific welfare considerations are discussed, and data gaps and areas for further research are identified. The guidance is based upon a systematic review of the scientific literature, survey of the international epilepsy research community, consultation with veterinarians and animal care and welfare officers, and the expert opinion and practical experience of the members of a Working Group convened by the United Kingdom's National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs).
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21
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Nagy LR, Featherstone RE, Hahn CG, Siegel SJ. Delayed emergence of behavioral and electrophysiological effects following juvenile ketamine exposure in mice. Transl Psychiatry 2015; 5:e635. [PMID: 26371763 PMCID: PMC5068812 DOI: 10.1038/tp.2015.111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 05/05/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022] Open
Abstract
Frequent ketamine abuse in adulthood correlates with increased risk of psychosis, as well as cognitive deficits, including disruption of higher-order executive function and memory formation. Although the primary abusers of ketamine are adolescents and young adults, few studies have evaluated its effects on juvenile cognition. Therefore, the current study analyzes the effect of adolescent ketamine exposure on cognitive development. Juvenile mice (4 weeks of age) were exposed to chronic ketamine (20 mg kg(-1), i.p. daily) for 14 days. Mice were tested immediately after exposure in the juvenile period (7 weeks of age) and again as adults (12 weeks of age). Measures included electroencephalography (EEG) in response to auditory stimulation, the social choice test, and a 6-arm radial water maze task. Outcome measures include low-frequency EEG responses, event-related potential (ERP) amplitudes, indices of social behavior and indices of spatial working memory. Juvenile exposure to ketamine was associated with electrophysiological abnormalities in adulthood, particularly in induced theta power and the P80 ERP. The social choice test revealed that ketamine-exposed mice failed to exhibit the same age-related decrease in social interaction time as controls. Ketamine-exposed mice outperformed control mice as juveniles on the radial water maze task, but did not show the same age-related improvement as adult controls. These data support the hypothesis that juvenile exposure to ketamine produces long-lasting changes in brain function that are characterized by a failure to progress along normal developmental trajectories.
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Affiliation(s)
- L R Nagy
- Department of Psychiatry, Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA
| | - R E Featherstone
- Department of Psychiatry, Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA
| | - C G Hahn
- Department of Psychiatry, Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA
| | - S J Siegel
- Department of Psychiatry, Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA 19104, USA. E-mail:
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22
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Wu C, Wang J, Peng J, Patel N, Huang Y, Gao X, Aljarallah S, Eubanks JH, McDonald R, Zhang L. Modeling early-onset post-ischemic seizures in aging mice. Exp Neurol 2015; 271:1-12. [PMID: 25943585 PMCID: PMC4758832 DOI: 10.1016/j.expneurol.2015.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/24/2015] [Accepted: 04/28/2015] [Indexed: 12/26/2022]
Abstract
Stroke is the leading cause of seizures and epilepsy in the aged population, with post-stroke seizures being a poor prognostic factor. The pathological processes underlying post-stroke seizures are not well understood and studies of these seizures in aging/aged animals remain scarce. Therefore, our primary objective was to model post-stroke seizures in aging mice (C57 black strain, 16-20 months-old), with a focus on early-onset, convulsive seizures that occur within 24-hours of brain ischemia. We utilized a middle cerebral artery occlusion model and examined seizure activity and brain injury using combined behavioral and electroencephalographic monitoring and histological assessments. Aging mice exhibited vigorous convulsive seizures within hours of the middle cerebral artery occlusion. These seizures manifested with jumping, rapid running, barrel-rolling and/or falling all in the absence of hippocampal-cortical electrographic discharges. Seizure development was closely associated with severe brain injury and acute mortality. Anticonvulsive treatments after seizure occurrence offered temporary seizure control but failed to improve animal survival. A separate cohort of adult mice (6-8 months-old) exhibited analogous early-onset convulsive seizures following the middle cerebral artery occlusion but had better survival outcomes following anticonvulsive treatment. Collectively, our data suggest that early-onset convulsive seizures are a result of severe brain ischemia in aging animals.
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Affiliation(s)
- Chiping Wu
- Toronto Western Research Institute, University Health Network, Canada
| | - Justin Wang
- Toronto Western Research Institute, University Health Network, Canada
| | - Jessie Peng
- Toronto Western Research Institute, University Health Network, Canada
| | - Nisarg Patel
- Toronto Western Research Institute, University Health Network, Canada
| | - Yayi Huang
- Toronto Western Research Institute, University Health Network, Canada
| | - Xiaoxing Gao
- Toronto Western Research Institute, University Health Network, Canada
| | - Salman Aljarallah
- Toronto Western Research Institute, University Health Network, Canada; Neurology Unit, Department of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James H Eubanks
- Toronto Western Research Institute, University Health Network, Canada; Department of Surgery (Neurosurgery), University of Toronto, Canada
| | - Robert McDonald
- Department of Neuroscience, University of Lethbridge, Canada
| | - Liang Zhang
- Toronto Western Research Institute, University Health Network, Canada; Department of Medicine (Neurology), University of Toronto, Canada.
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Kim J, Lee SE, Shin J, Jung HH, Kim SJ, Chang JW. The neuromodulation of neuropathic pain by measuring pain response rate and pain response duration in animal. J Korean Neurosurg Soc 2015; 57:6-11. [PMID: 25674337 PMCID: PMC4323508 DOI: 10.3340/jkns.2015.57.1.6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 03/31/2014] [Accepted: 04/09/2014] [Indexed: 12/02/2022] Open
Abstract
Objective Neuropathic pain causes patients feel indescribable pain. Deep Brain Stimulation (DBS) is one of the treatment methods in neuropathic pain but the action mechanism is still unclear. To study the effect and mechanism of analgesic effects from DBS in neuropathic pain and to enhance the analgesic effect of DBS, we stimulated the ventral posterolateral nucleus (VPL) in rats. Methods To observe the effect from VPL stimulation, we established 3 groups : normal group (Normal group), neuropathic pain group (Pain group) and neuropathic pain+DBS group (DBS group). Rats in DBS group subjected to electrical stimulation and the target is VPL. Results We observed the behavioral changes by DBS in VPL (VPL-DBS) on neuropathic pain rats. In our study, the pain score which is by conventional test method was effectively decreased. In specific, the time of showing withdrawal response from painful stimulation which is not used measuring method in our animal model was also decreased by DBS. Conclusion The VPL is an effective target on pain modulation. Specifically we could demonstrate changes of pain response duration which is not used, and it was also significantly meaningful. We thought that this study would be helpful in understanding the relation between VPL-DBS and neuropathic pain.
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Affiliation(s)
- Jinhyung Kim
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea. ; Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Eun Lee
- School of Electrical Engineering and Computer Science, Seoul National University, Seoul, Korea. ; Nano Bioelectronics and System Research Center, Seoul National University, Seoul, Korea
| | - Jaewoo Shin
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Hyun Ho Jung
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Sung June Kim
- School of Electrical Engineering and Computer Science, Seoul National University, Seoul, Korea. ; Nano Bioelectronics and System Research Center, Seoul National University, Seoul, Korea. ; Inter-University Semiconductor Research Center, Seoul National University, Seoul, Korea
| | - Jin Woo Chang
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea. ; Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
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Jeffrey M, Lang M, Gane J, Chow E, Wu C, Zhang L. Novel anticonvulsive effects of progesterone in a mouse model of hippocampal electrical kindling. Neuroscience 2013; 257:65-75. [PMID: 24215976 DOI: 10.1016/j.neuroscience.2013.10.074] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 10/07/2013] [Accepted: 10/30/2013] [Indexed: 12/28/2022]
Abstract
Progesterone is a known anticonvulsant, with its inhibitory effects generally attributed to its secondary metabolite, 5α,3α-tetrahydroprogesterone (THP), and THP's enhancement of GABAA receptor activity. Accumulating evidence, however, suggests that progesterone may have non-genomic actions independent of the GABAA receptor. In this study, we explored THP/GABAA-independent anticonvulsive actions of progesterone in a mouse model of hippocampal kindling and in mouse entorhinal slices in vitro. Specifically, we examined the effects of progesterone in kindled mice with or without pretreatments with finasteride, a 5α-reductase inhibitor known to block the metabolism of progesterone to THP. In addition, we examined the effects of progesterone on entorhinal epileptiform potentials in the presence of a GABAA receptor antagonist picrotoxin and finasteride. Adult male mice were kindled via a daily stimulation protocol. Electroencephalographic (EEG) discharges were recorded from the hippocampus or cortex to assess "focal" or "generalized" seizure activity. Kindled mice were treated with intra-peritoneal injections of progesterone (10, 35, 100 and 160mg/kg) with or without finasteride pretreatment (50 or 100mg/kg), THP (1, 3.5, 10 and 30mg/kg), midazolam (2mg/kg) and carbamazepine (50mg/kg). Entorhinal cortical slices were prepared from naïve young mice, and repetitive epileptiform potentials were induced by 4-aminopyridine (100μM), picrotoxin (100μM) and finasteride (1μM). Pretreatment with finasteride did not abolish the anticonvulsant effects of progesterone. In finasteride-pretreated mice, progesterone at 100 and 160mg/kg decreased cortical but not hippocampal afterdischarges (ADs). Carbamazepine mimicked the effects of progesterone with finasteride pretreatments in decreasing cortical discharges and motor seizures, whereas midazolam produced effects similar to progesterone alone or THP in decreasing hippocampal ADs and motor seizures. In brain slices, progesterone at 1μM inhibited entorhinal epileptiform potentials in the presence of picrotoxin and finasteride. We suggest that progesterone may have THP/GABAA-dependent and independent anticonvulsive actions in the hippocampal-kindled mouse model.
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Affiliation(s)
- M Jeffrey
- Department of Pharmacology and Toxicology, University of Toronto, Canada; Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada; University of Toronto Epilepsy Research Program, Canada
| | - M Lang
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada
| | - J Gane
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada
| | - E Chow
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada
| | - C Wu
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada; University of Toronto Epilepsy Research Program, Canada
| | - L Zhang
- Department of Medicine (Neurology), University of Toronto, Canada; Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada; University of Toronto Epilepsy Research Program, Canada.
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Lang M, Wither RG, Colic S, Wu C, Monnier PP, Bardakjian BL, Zhang L, Eubanks JH. Rescue of behavioral and EEG deficits in male and female Mecp2-deficient mice by delayed Mecp2 gene reactivation. Hum Mol Genet 2013; 23:303-18. [PMID: 24009314 PMCID: PMC3869352 DOI: 10.1093/hmg/ddt421] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mutations of the X-linked gene encoding methyl CpG binding protein type 2 (MECP2) are the predominant cause of Rett syndrome, a severe neurodevelopmental condition that affects primarily females. Previous studies have shown that major phenotypic deficits arising from MeCP2-deficiency may be reversible, as the delayed reactivation of the Mecp2 gene in Mecp2-deficient mice improved aspects of their Rett-like phenotype. While encouraging for prospective gene replacement treatments, it remains unclear whether additional Rett syndrome co-morbidities recapitulated in Mecp2-deficient mice will be similarly responsive to the delayed reintroduction of functional Mecp2. Here, we show that the delayed reactivation of Mecp2 in both male and female Mecp2-deficient mice rescues established deficits in motor and anxiety-like behavior, epileptiform activity, cortical and hippocampal electroencephalogram patterning and thermoregulation. These findings indicate that neural circuitry deficits arising from the deficiency in Mecp2 are not engrained, and provide further evidence that delayed restoration of Mecp2 function can improve a wide spectrum of the Rett-like deficits recapitulated by Mecp2-deficient mice.
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Affiliation(s)
- Min Lang
- Division of Genetics and Development and
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Jeffrey M, Lang M, Gane J, Wu C, Burnham WM, Zhang L. A reliable method for intracranial electrode implantation and chronic electrical stimulation in the mouse brain. BMC Neurosci 2013; 14:82. [PMID: 23914984 PMCID: PMC3750568 DOI: 10.1186/1471-2202-14-82] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 08/02/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Electrical stimulation of brain structures has been widely used in rodent models for kindling or modeling deep brain stimulation used clinically. This requires surgical implantation of intracranial electrodes and subsequent chronic stimulation in individual animals for several weeks. Anchoring screws and dental acrylic have long been used to secure implanted intracranial electrodes in rats. However, such an approach is limited when carried out in mouse models as the thin mouse skull may not be strong enough to accommodate the anchoring screws. We describe here a screw-free, glue-based method for implanting bipolar stimulating electrodes in the mouse brain and validate this method in a mouse model of hippocampal electrical kindling. METHODS Male C57 black mice (initial ages of 6-8 months) were used in the present experiments. Bipolar electrodes were implanted bilaterally in the hippocampal CA3 area for electrical stimulation and electroencephalographic recordings. The electrodes were secured onto the skull via glue and dental acrylic but without anchoring screws. A daily stimulation protocol was used to induce electrographic discharges and motor seizures. The locations of implanted electrodes were verified by hippocampal electrographic activities and later histological assessments. RESULTS Using the glue-based implantation method, we implanted bilateral bipolar electrodes in 25 mice. Electrographic discharges and motor seizures were successfully induced via hippocampal electrical kindling. Importantly, no animal encountered infection in the implanted area or a loss of implanted electrodes after 4-6 months of repetitive stimulation/recording. CONCLUSION We suggest that the glue-based, screw-free method is reliable for chronic brain stimulation and high-quality electroencephalographic recordings in mice. The technical aspects described this study may help future studies in mouse models.
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Affiliation(s)
- Melanie Jeffrey
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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27
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Hippocampal excitability is increased in aged mice. Exp Neurol 2013; 247:710-9. [PMID: 23510762 DOI: 10.1016/j.expneurol.2013.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 03/05/2013] [Accepted: 03/08/2013] [Indexed: 12/22/2022]
Abstract
Aging is known to be associated with a high risk of developing seizure disorders. Currently, the mechanisms underlying this increased seizure susceptibility are not fully understood. Several previous studies have shown a loss of subgroups of GABAergic inhibitory interneurons in the hippocampus of aged rodents, yet the network excitability intrinsic to the aged hippocampus remains to be elucidated. The aim of this study is to examine age-dependent changes of hippocampal network activities in young adult (3-5 months), aging (16-18 months), and aged (24-28 months) mice. We conducted intracranial electroencephalographic (EEG) recordings in free-moving animals and extracellular recordings in hippocampal slices in vitro. EEG recordings revealed frequent spikes in aging and aged mice but only occasionally in young adults. These EEG spikes were suppressed following diazepam administration. Spontaneous field potentials with large amplitudes were frequently observed in hippocampal slices of aged mice but rarely in slices from young adults. These spontaneous field potentials originated from the CA3 area and their generation was dependent upon the excitatory glutamatergic activity. We therefore postulate that hippocampal network excitability is increased in aged mice and that such hyperactivity may be relevant to the increased seizure susceptibility observed in aged subjects.
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28
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Lang M, Wither RG, Brotchie JM, Wu C, Zhang L, Eubanks JH. Selective preservation of MeCP2 in catecholaminergic cells is sufficient to improve the behavioral phenotype of male and female Mecp2-deficient mice. Hum Mol Genet 2012; 22:358-71. [PMID: 23077217 DOI: 10.1093/hmg/dds433] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused primarily by mutations of the X-linked MECP2 gene. Although the loss of MeCP2 function affects many neural systems, impairments of catecholaminergic function have been hypothesized to underlie several of the cardinal behavioral deficits of RTT patients and Mecp2-deficient mice. Although recent Mecp2 reactivation studies indicate that RTT may be a reversible condition, it remains unclear whether specifically preserving Mecp2 function within a specific system will be sufficient to convey beneficial effects. Here, we test whether the selective preservation of Mecp2 within catecholaminergic cells will improve the phenotype of Mecp2-deficient mice. Our results show that this targeted preservation of Mecp2 significantly improves the lifespan, phenotypic severity and cortical epileptiform discharge activity of both male and female Mecp2-deficient mice. Further, we found that the catecholaminergic preservation of Mecp2 also improves the ambulatory rate, rearing activity, motor coordination, anxiety and nest-building performances of Mecp2-deficient mice of each gender. Interestingly, our results also revealed a gender-specific improvement, as specific cortical and hippocampal electroencephalographic abnormalities were significantly improved in male, but not female, rescue mice. Collectively, these results support the role of the catecholaminergic system in the pathogenesis of RTT and provide proof-of-principle that restoring MeCP2 function within this specific system could represent a treatment strategy for RTT.
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Affiliation(s)
- Min Lang
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
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VPL-DBS on neuropathic pain rat model is effective in mechanical allodynia than cold allodynia. Neurol Sci 2012; 33:1265-70. [PMID: 22562402 DOI: 10.1007/s10072-012-1097-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 04/12/2012] [Indexed: 10/28/2022]
Abstract
Recently, deep brain stimulation (DBS) is widely used in various types of neurodegenerative disorders for minimal invasiveness and safety of the procedure. Deep brain stimulation is consistently applied for the treatment of patients with neuropathic pain even though the success rate is not as high as other neurodegenerative disorders. Furthermore, it is also unclear how DBS improves neuropathic pain. In this study, we investigated the role of DBS following the stimulation parameter for analgesic effect on mechanical allodynia and cold allodynia in neuropathic pain rats. We used a sciatic nerve injury model to induce neuropathic pain, and observed responses to mechanical and cold stimulation by the von Frey test and acetone test, respectively. We classified the rats into four groups: naïve (naïve, n = 10), naïve + DBS (N + DBS, n = 10), neuropathic pain (NP, n = 10), and neuropathic pain + DBS (NP + DBS, n = 10). We inserted the DBS electrode into the ventral posterolateral nucleus (VPL) into the rats (VPL-DBS). The score for mechanical allodynia was significantly decreased in NP + DBS group (p < 0.01). However, the score for cold allodynia did not significantly drop in any groups including NP + DBS group (p > 0.05). In this study, we found that the electrical stimulation of the VPL works more effectively with mechanical allodynia than cold one, and pain signal induced by mechanical stimulus and cold stimulus may be processed through different pathways in the brain.
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El-Hayek YH, Wu C, Zhang L. Early suppression of intracranial EEG signals predicts ischemic outcome in adult mice following hypoxia-ischemia. Exp Neurol 2011; 231:295-303. [PMID: 21821027 DOI: 10.1016/j.expneurol.2011.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 07/03/2011] [Accepted: 07/17/2011] [Indexed: 11/18/2022]
Abstract
The objective of this study is to determine whether early alterations in intracranial EEG activity predict overall outcome in non-anesthetized adult mice following hypoxia-ischemia (HI). Adult C57BL/6 mice received surgical implantation of bilateral intracranial EEG electrodes in the hippocampus and cerebral cortex. Animals were subjected to a hypoxic-ischemic (HI) episode consisting of permanent occlusion of the right common carotid artery and subsequent systemic hypoxia (8% O(2) for 30 min). EEG activities were sorted based on the observance of motor seizures, poor physical outcome, brain injury, and mortality. EEG signals were quantified as amplitude, variance, and root mean square, and early alterations in these parameters were compared. Animals with poor-HI outcome exhibited longer and more profound suppression of EEG signals in the hippocampus ipsilateral to the carotid artery occlusion during HI. Of the parameters chosen to quantify EEG activity, root mean square demonstrated the greatest sensitivity in predicting subsequent outcome. Thus, ipsilateral hippocampal EEG signals are a reliable early marker for assessing HI outcome in adult mice, and further characterization of ischemic EEG signals may aid in the development of novel quantitative variables for use in animal models of experimental cerebral ischemia.
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31
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Dong-Hyun Baek, Ji Soo Park, Eun-Joong Lee, Su Jung Shin, Jin-Hee Moon, Pak JJ, Sang-Hoon Lee. Interconnection of Multichannel Polyimide Electrodes Using Anisotropic Conductive Films (ACFs) for Biomedical Applications. IEEE Trans Biomed Eng 2011; 58:1466-73. [DOI: 10.1109/tbme.2010.2102020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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El-Hayek YH, Wu C, Chen R, Al-Sharif AR, Huang S, Patel N, Du C, Ruff CA, Fehlings MG, Carlen PL, Zhang L. Acute Postischemic Seizures Are Associated with Increased Mortality and Brain Damage in Adult Mice. Cereb Cortex 2011; 21:2863-75. [DOI: 10.1093/cercor/bhr080] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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33
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del Campo CM, Velázquez JLP, Freire MAC. EEG recording in rodents, with a focus on epilepsy. ACTA ACUST UNITED AC 2010; Chapter 6:Unit 6.24. [PMID: 19802816 DOI: 10.1002/0471142301.ns0624s49] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This unit describes the materials, methods, and analytical techniques available for the study of electrical activity of neural tissue in rodents in both homeostatic and disease states, with emphasis on epileptogenesis. A table containing a list of suppliers of relevant materials and equipment is also provided.
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D'Cruz JA, Wu C, Zahid T, El-Hayek Y, Zhang L, Eubanks JH. Alterations of cortical and hippocampal EEG activity in MeCP2-deficient mice. Neurobiol Dis 2010; 38:8-16. [PMID: 20045053 DOI: 10.1016/j.nbd.2009.12.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 12/18/2009] [Accepted: 12/20/2009] [Indexed: 11/17/2022] Open
Abstract
Rett syndrome is a pediatric neurological condition caused by mutations of the gene encoding the transcriptional regulator MECP2. In this study, we examined cortical and hippocampal electroencephalographic (EEG) activity in male and female MeCP2-deficient mice at symptomatic stages during different behavioral states. During acute sleep, MeCP2-deficient mice displayed normal delta-like activity in cortex and sharp-wave activity in hippocampus. However, when the mice were awake but immobile, abnormal spontaneous, rhythmic EEG discharges of 6-9 Hz were readily detected in the somatosensory cortex. During exploratory activity, MeCP2-deficient mice displayed clear theta rhythm activity in hippocampus, but its peak frequency was significantly attenuated compared to wild type. Collectively, these findings indicate that a deficiency in MeCP2 function in mice leads to alterations in EEG activity with similarities to what has been observed clinically in Rett syndrome patients.
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Affiliation(s)
- Jennifer Anne D'Cruz
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
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35
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An improved screw-free method for electrode implantation and intracranial electroencephalographic recordings in mice. Behav Res Methods 2009; 41:736-41. [PMID: 19587186 DOI: 10.3758/brm.41.3.736] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We recently developed a glue-based method for the implantation of intracranial electrodes in mice. Our approach is to secure a preconstructed electrode array using a cyanoacrylate-based glue (similar to Krazy Glue). This method is applicable to both young and aging mice and is suitable for long-term electroencephalographic recordings. In the present experiment, we explored whether the glue-based method is capable of securing individual electrodes in addition to securing the electrode array. C57 black mice aged 25-35 days or 13-19 months were operated on under isoflurane anesthesia. Monopolar or bipolar electrodes were inserted independently in the ipsilateral hippocampal CA3 and entorhinal cortical areas, and they were fixed onto the skull using the glue together with dental acrylic, but without anchoring screws. We found that the implanted electrodes were stable and allowed repeat intracranial recordings and electrical stimulation in freely moving mice.
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36
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Arrested maturation of excitatory synapses in autosomal dominant lateral temporal lobe epilepsy. Nat Med 2009; 15:1208-14. [PMID: 19701204 PMCID: PMC2759408 DOI: 10.1038/nm.2019] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 07/28/2009] [Indexed: 02/08/2023]
Abstract
A subset of central glutamatergic synapses are coordinatelypruned and matured by unresolved mechanisms during early postnatal life. We report that human epilepsy gene LGI1, mutated in autosomal dominant lateral temporal lobe epilepsy (ADLTE), mediates this process in hippocampus. We introduced full-length genes encoding (1) ADLTE truncated mutant LGI1 (835delC) and (2) excess wild-type LGI1 proteins into transgenic mice. We discovered that the normal postnatal Kv1 channel-dependent down-regulation of presynaptic release probability and Src kinase-related decrease of postsynaptic NR2B/NR2A ratio were arrested by ADLTE mutant LGI1, and contrastingly, were magnified by excess wild-type LGI1. Concurrently, mutant LGI1 inhibited dendritic pruning and increased the spine density to markedly increase excitatory transmission. Inhibitory transmission, by contrast, was unaffected. Furthermore, mutant LGI1 promoted epileptiform discharge in vitro and kindling epileptogenesis in vivo with partial GABAA receptor blockade. Thus, LGI1 represents the first human gene mutated to promote epilepsy through impaired glutamatergic circuit maturation.
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Repeated hypoxic episodes induce seizures and alter hippocampal network activities in mice. Neuroscience 2009; 161:599-613. [DOI: 10.1016/j.neuroscience.2009.03.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 02/08/2009] [Accepted: 03/15/2009] [Indexed: 11/23/2022]
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