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Capitano F, Kuchenbuch M, Lavigne J, Chaptoukaev H, Zuluaga MA, Lorenzi M, Nabbout R, Mantegazza M. Preictal dysfunctions of inhibitory interneurons paradoxically lead to their rebound hyperactivity and to low-voltage-fast onset seizures in Dravet syndrome. Proc Natl Acad Sci U S A 2024; 121:e2316364121. [PMID: 38809712 PMCID: PMC11161744 DOI: 10.1073/pnas.2316364121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 05/01/2024] [Indexed: 05/31/2024] Open
Abstract
Epilepsies have numerous specific mechanisms. The understanding of neural dynamics leading to seizures is important for disclosing pathological mechanisms and developing therapeutic approaches. We investigated electrographic activities and neural dynamics leading to convulsive seizures in patients and mouse models of Dravet syndrome (DS), a developmental and epileptic encephalopathy in which hypoexcitability of GABAergic neurons is considered to be the main dysfunction. We analyzed EEGs from DS patients carrying a SCN1A pathogenic variant, as well as epidural electrocorticograms, hippocampal local field potentials, and hippocampal single-unit neuronal activities in Scn1a+/- and Scn1aRH/+ DS mice. Strikingly, most seizures had low-voltage-fast onset in both patients and mice, which is thought to be generated by hyperactivity of GABAergic interneurons, the opposite of the main pathological mechanism of DS. Analyzing single-unit recordings, we observed that temporal disorganization of the firing of putative interneurons in the period immediately before the seizure (preictal) precedes the increase of their activity at seizure onset, together with the entire neuronal network. Moreover, we found early signatures of the preictal period in the spectral features of hippocampal and cortical field potential of Scn1a mice and of patients' EEG, which are consistent with the dysfunctions that we observed in single neurons and that allowed seizure prediction. Therefore, the perturbed preictal activity of interneurons leads to their hyperactivity at the onset of generalized seizures, which have low-voltage-fast features that are similar to those observed in other epilepsies and are triggered by hyperactivity of GABAergic neurons. Preictal spectral features may be used as predictive seizure biomarkers.
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Affiliation(s)
- Fabrizio Capitano
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- CNRS UMR 7275, Valbonne-Sophia Antipolis06560, France
- Inserm U1323, Valbonne-Sophia Antipolis06650, France
| | - Mathieu Kuchenbuch
- Reference Centre for Rare Epilepsies, Member of European Reference Network EpiCARE, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, Paris75015, France
- Laboratory of Translational Research for Neurological Disorders, Inserm UMR 1163, Imagine Institute, Université Paris Cité, Paris75015, France
| | - Jennifer Lavigne
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- CNRS UMR 7275, Valbonne-Sophia Antipolis06560, France
- Inserm U1323, Valbonne-Sophia Antipolis06650, France
| | | | | | - Marco Lorenzi
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- Epione Research team, Inria Center of Université Côte d’Azur, Biot-Sophia Antipolis06410, France
| | - Rima Nabbout
- Reference Centre for Rare Epilepsies, Member of European Reference Network EpiCARE, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, Paris75015, France
- Laboratory of Translational Research for Neurological Disorders, Inserm UMR 1163, Imagine Institute, Université Paris Cité, Paris75015, France
| | - Massimo Mantegazza
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- CNRS UMR 7275, Valbonne-Sophia Antipolis06560, France
- Inserm U1323, Valbonne-Sophia Antipolis06650, France
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Streng ML, Kottke BW, Wasserman EM, Zecker L, Luong L, Ebner TJ, Krook-Magnuson E. Early and widespread engagement of the cerebellum during hippocampal epileptiform activity Format: Brief Communication. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.14.593969. [PMID: 38798649 PMCID: PMC11118491 DOI: 10.1101/2024.05.14.593969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Despite research illustrating the cerebellum may be a critical circuit element in the epilepsies, remarkably little is known about cerebellar engagement during seizures. We therefore implemented a novel method for repeated imaging of the cerebellum in awake, chronically epileptic animals. We found widespread changes in cerebellar calcium signals during behavioral seizures and during hippocampal seizures that remained electrographic only, arguing against cerebellar modulation simply reflecting motor components. Moreover, even brief interictal spikes produced widespread alterations in cerebellar activity. Changes were noted in the anterior and posterior cerebellum, along the midline, and both ipsilaterally and contralaterally to the seizure focus. Remarkably, changes in the cerebellum also occurred prior to any noticeable change in the hippocampal electrographic recordings, suggesting a special relationship between the cerebellum and hippocampal epileptiform activity. Together these results underscore the importance of the cerebellum in epilepsy, warranting a more consistent consideration of the cerebellum when evaluating epilepsy patients.
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McFarlan AR, Guo C, Gomez I, Weinerman C, Liang TA, Sjöström PJ. The spike-timing-dependent plasticity of VIP interneurons in motor cortex. Front Cell Neurosci 2024; 18:1389094. [PMID: 38706517 PMCID: PMC11066220 DOI: 10.3389/fncel.2024.1389094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 04/09/2024] [Indexed: 05/07/2024] Open
Abstract
The plasticity of inhibitory interneurons (INs) plays an important role in the organization and maintenance of cortical microcircuits. Given the many different IN types, there is an even greater diversity in synapse-type-specific plasticity learning rules at excitatory to excitatory (E→I), I→E, and I→I synapses. I→I synapses play a key disinhibitory role in cortical circuits. Because they typically target other INs, vasoactive intestinal peptide (VIP) INs are often featured in I→I→E disinhibition, which upregulates activity in nearby excitatory neurons. VIP IN dysregulation may thus lead to neuropathologies such as epilepsy. In spite of the important activity regulatory role of VIP INs, their long-term plasticity has not been described. Therefore, we characterized the phenomenology of spike-timing-dependent plasticity (STDP) at inputs and outputs of genetically defined VIP INs. Using a combination of whole-cell recording, 2-photon microscopy, and optogenetics, we explored I→I STDP at layer 2/3 (L2/3) VIP IN outputs onto L5 Martinotti cells (MCs) and basket cells (BCs). We found that VIP IN→MC synapses underwent causal long-term depression (LTD) that was presynaptically expressed. VIP IN→BC connections, however, did not undergo any detectable plasticity. Conversely, using extracellular stimulation, we explored E→I STDP at inputs to VIP INs which revealed long-term potentiation (LTP) for both causal and acausal timings. Taken together, our results demonstrate that VIP INs possess synapse-type-specific learning rules at their inputs and outputs. This suggests the possibility of harnessing VIP IN long-term plasticity to control activity-related neuropathologies such as epilepsy.
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Affiliation(s)
- Amanda R. McFarlan
- Centre for Research in Neuroscience, BRaIN Program, Department of Neurology and Neurosurgery, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Connie Guo
- Centre for Research in Neuroscience, BRaIN Program, Department of Neurology and Neurosurgery, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Isabella Gomez
- Centre for Research in Neuroscience, BRaIN Program, Department of Neurology and Neurosurgery, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Chaim Weinerman
- Centre for Research in Neuroscience, BRaIN Program, Department of Neurology and Neurosurgery, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Tasha A. Liang
- Centre for Research in Neuroscience, BRaIN Program, Department of Neurology and Neurosurgery, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - P. Jesper Sjöström
- Centre for Research in Neuroscience, BRaIN Program, Department of Neurology and Neurosurgery, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
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Stern MA, Cole ER, Gross RE, Berglund K. Seizure event detection using intravital two-photon calcium imaging data. NEUROPHOTONICS 2024; 11:024202. [PMID: 38274784 PMCID: PMC10809036 DOI: 10.1117/1.nph.11.2.024202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/20/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024]
Abstract
Significance Intravital cellular calcium imaging has emerged as a powerful tool to investigate how different types of neurons interact at the microcircuit level to produce seizure activity, with newfound potential to understand epilepsy. Although many methods exist to measure seizure-related activity in traditional electrophysiology, few yet exist for calcium imaging. Aim To demonstrate an automated algorithmic framework to detect seizure-related events using calcium imaging-including the detection of pre-ictal spike events, propagation of the seizure wavefront, and terminal spreading waves for both population-level activity and that of individual cells. Approach We developed an algorithm for precise recruitment detection of population and individual cells during seizure-associated events, which broadly leverages averaged population activity and high-magnitude slope features to detect single-cell pre-ictal spike and seizure recruitment. We applied this method to data recorded using awake in vivo two-photon calcium imaging during pentylenetetrazol-induced seizures in mice. Results We demonstrate that our detected recruitment times are concordant with visually identified labels provided by an expert reviewer and are sufficiently accurate to model the spatiotemporal progression of seizure-associated traveling waves. Conclusions Our algorithm enables accurate cell recruitment detection and will serve as a useful tool for researchers investigating seizure dynamics using calcium imaging.
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Affiliation(s)
- Matthew A. Stern
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, Georgia, United States
| | - Eric R. Cole
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, Georgia, United States
- Emory University, Georgia Institute of Technology, Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Robert E. Gross
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, Georgia, United States
- Emory University, Georgia Institute of Technology, Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Ken Berglund
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, Georgia, United States
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Takahashi K, Rensing NR, Eultgen EM, Wang SH, Nelvagal HR, Le SQ, Roberts MS, Doray B, Han EB, Dickson PI, Wong M, Sands MS, Cooper JD. GABAergic interneurons contribute to the fatal seizure phenotype of CLN2 disease mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.29.587276. [PMID: 38585903 PMCID: PMC10996664 DOI: 10.1101/2024.03.29.587276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
GABAergic interneuron deficits have been implicated in the epileptogenesis of multiple neurological diseases. While epileptic seizures are a key clinical hallmark of CLN2 disease, a childhood-onset neurodegenerative lysosomal storage disorder caused by a deficiency of tripeptidyl peptidase 1 (TPP1), the etiology of these seizures remains elusive. Given that Cln2 R207X/R207X mice display fatal spontaneous seizures and an early loss of several cortical interneuron populations, we hypothesized that those two events might be causally related. To address this hypothesis, we first generated an inducible transgenic mouse expressing lysosomal membrane-tethered TPP1 (TPP1LAMP1) on the Cln2 R207X/R207X genetic background to study the cell-autonomous effects of cell-type-specific TPP1 deficiency. We crossed the TPP1LAMP1 mice with Vgat-Cre mice to introduce interneuron-specific TPP1 deficiency. Vgat-Cre ; TPP1LAMP1 mice displayed storage material accumulation in several interneuron populations both in cortex and striatum, and increased susceptibility to die after PTZ-induced seizures. Secondly, to test the role of GABAergic interneuron activity in seizure progression, we selectively activated these cells in Cln2 R207X/R207X mice using Designer Receptor Exclusively Activated by Designer Drugs (DREADDs) in in Vgat-Cre : Cln2 R207X/R207X mice. EEG monitoring revealed that DREADD-mediated activation of interneurons via chronic deschloroclozapine administration accelerated the onset of spontaneous seizures and seizure-associated death in Vgat-Cre : Cln2 R207X/R207X mice, suggesting that modulating interneuron activity can exert influence over epileptiform abnormalities in CLN2 disease. Taken together, these results provide new mechanistic insights into the underlying etiology of seizures and premature death that characterize CLN2 disease.
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Enger R, Heuser K. Astrocytes as critical players of the fine balance between inhibition and excitation in the brain: spreading depolarization as a mechanism to curb epileptic activity. FRONTIERS IN NETWORK PHYSIOLOGY 2024; 4:1360297. [PMID: 38405021 PMCID: PMC10884165 DOI: 10.3389/fnetp.2024.1360297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 01/25/2024] [Indexed: 02/27/2024]
Abstract
Spreading depolarizations (SD) are slow waves of complete depolarization of brain tissue followed by neuronal silencing that may play a role in seizure termination. Even though SD was first discovered in the context of epilepsy research, the link between SD and epileptic activity remains understudied. Both seizures and SD share fundamental pathophysiological features, and recent evidence highlights the frequent occurrence of SD in experimental seizure models. Human data on co-occurring seizures and SD are limited but suggestive. This mini-review addresses possible roles of SD during epileptiform activity, shedding light on SD as a potential mechanism for terminating epileptiform activity. A common denominator for many forms of epilepsy is reactive astrogliosis, a process characterized by morphological and functional changes to astrocytes. Data suggest that SD mechanisms are potentially perturbed in reactive astrogliosis and we propose that this may affect seizure pathophysiology.
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Affiliation(s)
- Rune Enger
- Letten Centre and GliaLab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Kjell Heuser
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
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Chen F, Dong X, Wang Z, Wu T, Wei L, Li Y, Zhang K, Ma Z, Tian C, Li J, Zhao J, Zhang W, Liu A, Shen H. Regulation of specific abnormal calcium signals in the hippocampal CA1 and primary cortex M1 alleviates the progression of temporal lobe epilepsy. Neural Regen Res 2024; 19:425-433. [PMID: 37488907 PMCID: PMC10503629 DOI: 10.4103/1673-5374.379048] [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: 02/06/2023] [Revised: 03/15/2023] [Accepted: 05/04/2023] [Indexed: 07/26/2023] Open
Abstract
Temporal lobe epilepsy is a multifactorial neurological dysfunction syndrome that is refractory, resistant to antiepileptic drugs, and has a high recurrence rate. The pathogenesis of temporal lobe epilepsy is complex and is not fully understood. Intracellular calcium dynamics have been implicated in temporal lobe epilepsy. However, the effect of fluctuating calcium activity in CA1 pyramidal neurons on temporal lobe epilepsy is unknown, and no longitudinal studies have investigated calcium activity in pyramidal neurons in the hippocampal CA1 and primary motor cortex M1 of freely moving mice. In this study, we used a multi-channel fiber photometry system to continuously record calcium signals in CA1 and M1 during the temporal lobe epilepsy process. We found that calcium signals varied according to the grade of temporal lobe epilepsy episodes. In particular, cortical spreading depression, which has recently been frequently used to represent the continuously and substantially increased calcium signals, was found to correspond to complex and severe behavioral characteristics of temporal lobe epilepsy ranging from grade II to grade V. However, vigorous calcium oscillations and highly synchronized calcium signals in CA1 and M1 were strongly related to convulsive motor seizures. Chemogenetic inhibition of pyramidal neurons in CA1 significantly attenuated the amplitudes of the calcium signals corresponding to grade I episodes. In addition, the latency of cortical spreading depression was prolonged, and the above-mentioned abnormal calcium signals in CA1 and M1 were also significantly reduced. Intriguingly, it was possible to rescue the altered intracellular calcium dynamics. Via simultaneous analysis of calcium signals and epileptic behaviors, we found that the progression of temporal lobe epilepsy was alleviated when specific calcium signals were reduced, and that the end-point behaviors of temporal lobe epilepsy were improved. Our results indicate that the calcium dynamic between CA1 and M1 may reflect specific epileptic behaviors corresponding to different grades. Furthermore, the selective regulation of abnormal calcium signals in CA1 pyramidal neurons appears to effectively alleviate temporal lobe epilepsy, thereby providing a potential molecular mechanism for a new temporal lobe epilepsy diagnosis and treatment strategy.
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Affiliation(s)
- Feng Chen
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
- Institute for Translational Neuroscience, the Second Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Xi Dong
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
- Institute for Translational Brain Research, Fudan University, Shanghai, China
| | - Zhenhuan Wang
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Tongrui Wu
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Liangpeng Wei
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
- Department of Radiology, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, China
| | - Yuanyuan Li
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Kai Zhang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Zengguang Ma
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Chao Tian
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Jing Li
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingyu Zhao
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Wei Zhang
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Aili Liu
- Laboratory of Neurobiology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Hui Shen
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, China
- Laboratory of Neurobiology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
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Southwell DG. Interneuron Transplantation for Drug-Resistant Epilepsy. Neurosurg Clin N Am 2024; 35:151-160. [PMID: 38000838 DOI: 10.1016/j.nec.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2023]
Abstract
Current epilepsy surgical techniques, such as brain resection, laser ablation, and neurostimulation, target seizure networks macroscopically, and they may yield an unfavorable balance between seizure reduction, procedural invasiveness, and neurologic morbidity. The transplantation of GABAergic interneurons is a regenerative technique for altering neural inhibition in cortical circuits, with potential as an alternative and minimally invasive approach to epilepsy treatment. This article (1) reviews some of the preclinical evidence supporting interneuron transplantation as an epilepsy therapy, (2) describes a first-in-human study of interneuron transplantation for epilepsy, and (3) considers knowledge gaps that stand before the effective clinical application of this novel treatment.
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Affiliation(s)
- Derek G Southwell
- Department of Neurosurgery, Graduate Program in Neurobiology, Duke University, DUMC 3807, 200 Trent Drive, Durham, NC 27710, USA.
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Rahimi S, Salami P, Matulewicz P, Schmuck A, Bukovac A, Ramos-Prats A, Tasan RO, Drexel M. The role of subicular VIP-expressing interneurons on seizure dynamics in the intrahippocampal kainic acid model of temporal lobe epilepsy. Exp Neurol 2023; 370:114580. [PMID: 37884187 DOI: 10.1016/j.expneurol.2023.114580] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/10/2023] [Accepted: 10/21/2023] [Indexed: 10/28/2023]
Abstract
The subiculum, a key output region of the hippocampus, is increasingly recognized as playing a crucial role in seizure initiation and spread. The subiculum consists of glutamatergic pyramidal cells, which show alterations in intrinsic excitability in the course of epilepsy, and multiple types of GABAergic interneurons, which exhibit varying characteristics in epilepsy. In this study, we aimed to assess the role of the vasoactive intestinal peptide interneurons (VIP-INs) of the ventral subiculum in the pathophysiology of temporal lobe epilepsy. We observed that an anatomically restricted inhibition of VIP-INs of the ventral subiculum was sufficient to reduce seizures in the intrahippocampal kainic acid model of epilepsy, changing the circadian rhythm of seizures, emphasizing the critical role of this small cell population in modulating TLE. As we expected, permanent unilateral or bilateral silencing of VIP-INs of the ventral subiculum in non-epileptic animals did not induce seizures or epileptiform activity. Interestingly, transient activation of VIP-INs of the ventral subiculum was enough to increase the frequency of seizures in the acute seizure model. Our results offer new perspectives on the crucial involvement of VIP-INs of the ventral subiculum in the pathophysiology of TLE. Given the observed predominant disinhibitory role of the VIP-INs input in subicular microcircuits, modifications of this input could be considered in the development of therapeutic strategies to improve seizure control.
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Affiliation(s)
- Sadegh Rahimi
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Pariya Salami
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Pawel Matulewicz
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Armin Schmuck
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Anneliese Bukovac
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Arnau Ramos-Prats
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ramon Osman Tasan
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Meinrad Drexel
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
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Wenzel M, Huberfeld G, Grayden DB, de Curtis M, Trevelyan AJ. A debate on the neuronal origin of focal seizures. Epilepsia 2023; 64 Suppl 3:S37-S48. [PMID: 37183507 DOI: 10.1111/epi.17650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/26/2023] [Accepted: 05/12/2023] [Indexed: 05/16/2023]
Abstract
A critical question regarding how focal seizures start is whether we can identify particular cell classes that drive the pathological process. This was the topic for debate at the recent International Conference for Technology and Analysis of Seizures (ICTALS) meeting (July 2022, Bern, CH) that we summarize here. The debate has been fueled in recent times by the introduction of powerful new ways to manipulate subpopulations of cells in relative isolation, mostly using optogenetics. The motivation for resolving the debate is to identify novel targets for therapeutic interventions through a deeper understanding of the etiology of seizures.
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Affiliation(s)
- Michael Wenzel
- Department of Epileptology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Gilles Huberfeld
- Neurology Department, Hopital Fondation Adolphe de Rothschild, Paris, France
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Medicine, St Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
- Graeme Clark Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marco de Curtis
- Epilepsy Unit, Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, Milan, Italy
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, UK
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Stern MA, Cole ER, Gross RE, Berglund K. Seizure Event Detection Using Intravital Two-Photon Calcium Imaging Data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.558338. [PMID: 37808822 PMCID: PMC10557641 DOI: 10.1101/2023.09.28.558338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Significance Genetic cellular calcium imaging has emerged as a powerful tool to investigate how different types of neurons interact at the microcircuit level to produce seizure activity, with newfound potential to understand epilepsy. Although many methods exist to measure seizure-related activity in traditional electrophysiology, few yet exist for calcium imaging. Aim To demonstrate an automated algorithmic framework to detect seizure-related events using calcium imaging - including the detection of pre-ictal spike events, propagation of the seizure wavefront, and terminal spreading waves for both population-level activity and that of individual cells. Approach We developed an algorithm for precise recruitment detection of population and individual cells during seizure-associated events, which broadly leverages averaged population activity and high-magnitude slope features to detect single-cell pre-ictal spike and seizure recruitment. We applied this method to data recorded using awake in vivo two-photon calcium imaging during pentylenetetrazol induced seizures in mice. Results We demonstrate that our detected recruitment times are concordant with visually identified labels provided by an expert reviewer and are sufficiently accurate to model the spatiotemporal progression of seizure-associated traveling waves. Conclusions Our algorithm enables accurate cell recruitment detection and will serve as a useful tool for researchers investigating seizure dynamics using calcium imaging.
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Affiliation(s)
- Matthew A. Stern
- Authors Contributed Equally
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, GA, United States
| | - Eric R. Cole
- Authors Contributed Equally
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, GA, United States
- Emory University and Georgia Institute of Technology, Coulter Department of Biomedical Engineering, Atlanta, GA, United States
| | - Robert E. Gross
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, GA, United States
- Emory University and Georgia Institute of Technology, Coulter Department of Biomedical Engineering, Atlanta, GA, United States
| | - Ken Berglund
- Emory University School of Medicine, Department of Neurosurgery, Atlanta, GA, United States
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Mueller JS, Tescarollo FC, Huynh T, Brenner DA, Valdivia DJ, Olagbegi K, Sangappa S, Chen SC, Sun H. Ictogenesis proceeds through discrete phases in hippocampal CA1 seizures in mice. Nat Commun 2023; 14:6010. [PMID: 37752179 PMCID: PMC10522592 DOI: 10.1038/s41467-023-41711-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
Epilepsy is characterized by spontaneous non-provoked seizures, yet the mechanisms that trigger a seizure and allow its evolution remain underexplored. To dissect out phases of ictogenesis, we evoked hypersynchronous activity with optogenetic stimulation. Focal optogenetic activation of putative excitatory neurons in the mouse hippocampal CA1 reliably evoked convulsive seizures in awake mice. A time-vs-time pulsogram plot characterized the evolution of the EEG pulse response from a light evoked response to induced seizure activity. Our results depict ictogenesis as a stepwise process comprised of three distinctive phases demarcated by two transition points. The induction phase undergoes the first transition to reverberant phase activity, followed by the second transition into the paroxysmal phase or a seizure. Non-seizure responses are confined to either induction or reverberant phases. The pulsogram was then constructed in seizures recorded from a murine model of temporal lobe epilepsy and it depicted a similar reverberance preceding spontaneous seizures. The discovery of these distinct phases of ictogenesis may offer means to abort a seizure before it develops.
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Affiliation(s)
- John-Sebastian Mueller
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Fabio C Tescarollo
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Trong Huynh
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
- Department of Surgery, Rutgers New Jersey Medical School, Newark, NJ, 07103, USA
| | - Daniel A Brenner
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Daniel J Valdivia
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Kanyin Olagbegi
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Sahana Sangappa
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Spencer C Chen
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Hai Sun
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA.
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13
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Zhao J, Yu Y, Han F, Wang Q. Regulating epileptiform discharges by heterogeneous interneurons in thalamocortical model. CHAOS (WOODBURY, N.Y.) 2023; 33:083128. [PMID: 37561121 DOI: 10.1063/5.0163243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 07/25/2023] [Indexed: 08/11/2023]
Abstract
Inhibitory interneurons in the cortex are abundant and have diverse roles, classified as parvalbumin (PV), somatostatin (SOM), and vasoactive intestinal polypeptide (VIP) according to chemically defined categories. Currently, their involvement with seizures has been partially uncovered in physiological terms. Here, we propose a corticothalamic model containing heterogeneous interneurons to study the effects of various interneurons on absence seizure dynamics by means of optogenetic stimulation. First, the important role of feedforward inhibition caused by SRN→PV→PN projections on seizures is verified. Then, we demonstrate that light activation targeting either PV or SOM INs can control seizures. Finally, with different inhibition contributions from PV INs and SOM INs, the possible disinhibitory effect of blue light acting on VIP INs is mainly discussed. The results suggest that depending on the inhibition degree of both types, the disinhibition brought about by the VIP INs will trigger seizures, will control seizures, and will not work or cause the PNs to tend toward a high saturation state with high excitability. The circuit mechanism and the related bifurcation characteristics in various cases are emphatically revealed. In the model presented, in addition to Hopf and saddle-node bifurcations, the system may also undergo period-doubling and torus bifurcations under stimulus action, with more complex dynamics. Our work may provide a theoretical basis for understanding and further exploring the role of heterogeneous interneurons, in particular, the VIP INs, a novel target, in absence seizures.
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Affiliation(s)
- Jinyi Zhao
- Department of Dynamics and Control, Beihang University, Beijing 100191, China
| | - Ying Yu
- School of Engineering Medicine, Beihang University, Beijing 100191, China
| | - Fang Han
- College of Information Science and Technology, Donghua University, Shanghai 201620, China
| | - Qingyun Wang
- Department of Dynamics and Control, Beihang University, Beijing 100191, China
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14
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Ledri M, Andersson M, Wickham J, Kokaia M. Optogenetics for controlling seizure circuits for translational approaches. Neurobiol Dis 2023:106234. [PMID: 37479090 DOI: 10.1016/j.nbd.2023.106234] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/02/2023] [Accepted: 07/19/2023] [Indexed: 07/23/2023] Open
Abstract
The advent of optogenetic tools has had a profound impact on modern neuroscience research, revolutionizing our understanding of the brain. These tools offer a remarkable ability to precisely manipulate specific groups of neurons with an unprecedented level of temporal precision, on the order of milliseconds. This breakthrough has significantly advanced our knowledge of various physiological and pathophysiological processes in the brain. Within the realm of epilepsy research, optogenetic tools have played a crucial role in investigating the contributions of different neuronal populations to the generation of seizures and hyperexcitability. By selectively activating or inhibiting specific neurons using optogenetics, researchers have been able to elucidate the underlying mechanisms and identify key players involved in epileptic activity. Moreover, optogenetic techniques have also been explored as innovative therapeutic strategies for treating epilepsy. These strategies aim to halt seizure progression and alleviate symptoms by utilizing the precise control offered by optogenetics. The application of optogenetic tools has provided valuable insights into the intricate workings of the brain during epileptic episodes. For instance, researchers have discovered how distinct interneuron populations contribute to the initiation of seizures (ictogenesis). They have also revealed how remote circuits in regions such as the cerebellum, septum, or raphe nuclei can interact with hyperexcitable networks in the hippocampus. Additionally, studies have demonstrated the potential of closed-loop systems, where optogenetics is combined with real-time monitoring, to enable precise, on-demand control of seizure activity. Despite the immense promise demonstrated by optogenetic approaches, it is important to acknowledge that many of these techniques are still in the early stages of development and have yet to reach potential clinical applications. The transition from experimental research to practical clinical use poses numerous challenges. In this review, we aim to introduce optogenetic tools, provide a comprehensive survey of their application in epilepsy research, and critically discuss their current potential and limitations in achieving successful clinical implementation for the treatment of human epilepsy. By addressing these crucial aspects, we hope to foster a deeper understanding of the current state and future prospects of optogenetics in epilepsy treatment.
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Affiliation(s)
- Marco Ledri
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - My Andersson
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - Jenny Wickham
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - Merab Kokaia
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden.
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15
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Graham RT, Parrish RR, Alberio L, Johnson EL, Owens L, Trevelyan AJ. Optogenetic stimulation reveals a latent tipping point in cortical networks during ictogenesis. Brain 2023; 146:2814-2827. [PMID: 36572952 PMCID: PMC10316782 DOI: 10.1093/brain/awac487] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 11/17/2022] [Accepted: 12/06/2022] [Indexed: 12/28/2022] Open
Abstract
Brain-state transitions are readily apparent from changes in brain rhythms,1 but are difficult to predict, suggestive that the underlying cause is latent to passive recording methods. Among the most important transitions, clinically, are the starts of seizures. We here show that an 'active probing' approach may have several important benefits for epileptic management, including by helping predict these transitions. We used mice expressing the optogenetic actuator, channelrhodopsin, in pyramidal cells, allowing this population to be stimulated in isolation. Intermittent stimulation at frequencies as low as 0.033 Hz (period = 30 s) delayed the onset of seizure-like events in an acute brain slice model of ictogenesis, but the effect was lost if stimulation was delivered at even lower frequencies (1/min). Notably, active probing additionally provides advance indication of when seizure-like activity is imminent, revealed by monitoring the postsynaptic response to stimulation. The postsynaptic response, recorded extracellularly, showed an all-or-nothing change in both amplitude and duration, a few hundred seconds before seizure-like activity began-a sufficient length of time to provide a helpful warning of an impending seizure. The change in the postsynaptic response then persisted for the remainder of the recording, indicative of a state change from a pre-epileptic to a pro-epileptic network. This occurred in parallel with a large increase in the stimulation-triggered Ca2+ entry into pyramidal dendrites, and a step increase in the number of evoked postsynaptic action potentials, both consistent with a reduction in the threshold for dendritic action potentials. In 0 Mg2+ bathing media, the reduced threshold was not associated with changes in glutamatergic synaptic function, nor of GABAergic release from either parvalbumin or somatostatin interneurons, but simulations indicate that the step change in the optogenetic response can instead arise from incremental increases in intracellular [Cl-]. The change in the response to stimulation was replicated by artificially raising intracellular [Cl-], using the optogenetic chloride pump, halorhodopsin. By contrast, increases in extracellular [K+] cannot account for the firing patterns in the response to stimulation, although this, and other cellular changes, may contribute to ictal initiation in other circumstances. We describe how these various cellular changes form a synergistic network of positive feedback mechanisms, which may explain the precipitous nature of seizure onset. This model of seizure initiation draws together several major lines of epilepsy research as well as providing an important proof-of-principle regarding the utility of open-loop brain stimulation for clinical management of the condition.
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Affiliation(s)
- Robert T Graham
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - R Ryley Parrish
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Laura Alberio
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Emily L Johnson
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Laura Owens
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew J Trevelyan
- Medical School, Newcastle University Biosciences Institute, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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16
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Diamond JM, Withers CP, Chapeton JI, Rahman S, Inati SK, Zaghloul KA. Interictal discharges in the human brain are travelling waves arising from an epileptogenic source. Brain 2023; 146:1903-1915. [PMID: 36729683 PMCID: PMC10411927 DOI: 10.1093/brain/awad015] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/27/2022] [Accepted: 01/08/2023] [Indexed: 02/03/2023] Open
Abstract
While seizure activity may be electrographically widespread, increasing evidence has suggested that ictal discharges may in fact represent travelling waves propagated from a focal seizure source. Interictal epileptiform discharges (IEDs) are an electrographic manifestation of excessive hypersynchronization of cortical activity that occur between seizures and are considered a marker of potentially epileptogenic tissue. The precise relationship between brain regions demonstrating IEDs and those involved in seizure onset, however, remains poorly understood. Here, we hypothesize that IEDs likewise reflect the receipt of travelling waves propagated from the same regions which give rise to seizures. Forty patients from our institution who underwent invasive monitoring for epilepsy, proceeded to surgery and had at least one year of follow-up were included in our study. Interictal epileptiform discharges were detected using custom software, validated by a clinical epileptologist. We show that IEDs reach electrodes in sequences with a consistent temporal ordering, and this ordering matches the timing of receipt of ictal discharges, suggesting that both types of discharges spread as travelling waves. We use a novel approach for localization of ictal discharges, in which time differences of discharge receipt at nearby electrodes are used to compute source location; similar algorithms have been used in acoustics and geophysics. We find that interictal discharges co-localize with ictal discharges. Moreover, interictal discharges tend to localize to the resection territory in patients with good surgical outcome and outside of the resection territory in patients with poor outcome. The seizure source may originate at, and also travel to, spatially distinct IED foci. Our data provide evidence that interictal discharges may represent travelling waves of pathological activity that are similar to their ictal counterparts, and that both ictal and interictal discharges emerge from common epileptogenic brain regions. Our findings have important clinical implications, as they suggest that seizure source localizations may be derived from interictal discharges, which are much more frequent than seizures.
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Affiliation(s)
- Joshua M Diamond
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - C Price Withers
- Clinical Epilepsy Section, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Julio I Chapeton
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shareena Rahman
- Office of the Clinical Director, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sara K Inati
- Clinical Epilepsy Section, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
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17
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Kravchenko JA, Goldberg EM, Mattis J. Optogenetic and chemogenetic manipulation of seizure threshold in mice. STAR Protoc 2023; 4:102019. [PMID: 36640370 PMCID: PMC9846020 DOI: 10.1016/j.xpro.2022.102019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/07/2022] [Accepted: 12/23/2022] [Indexed: 01/15/2023] Open
Abstract
Here, we present a protocol using optogenetics or chemogenetics to assess the neuronal circuits contributing to seizure initiation. Both approaches allow for targeted control of neuronal populations in vivo and can be combined with experimental manipulations to acutely induce seizures in rodent models. We describe how to (1) introduce and (2) activate optogenetic or chemogenetic actuators while (3) inducing seizures via hyperthermia in a mouse model of epilepsy. This protocol can be adapted for use in other induced seizure models. For complete details on the use and execution of this protocol, please refer to Mattis et al. (2022).1.
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Affiliation(s)
- Julia A Kravchenko
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Joanna Mattis
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
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18
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Goldenberg AM, Schmidt S, Mitelman R, Levy DR, Prigge M, Katz Y, Yizhar O, Beck H, Lampl I. Localized chemogenetic silencing of inhibitory neurons: a novel mouse model of focal cortical epileptic activity. Cereb Cortex 2023; 33:2838-2856. [PMID: 35788286 DOI: 10.1093/cercor/bhac245] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Focal cortical epilepsies are frequently refractory to available anticonvulsant drug therapies. One key factor contributing to this state is the limited availability of animal models that allow to reliably study focal cortical seizures and how they recruit surrounding brain areas in vivo. In this study, we selectively expressed the inhibitory chemogenetic receptor, hM4D, in GABAergic neurons in focal cortical areas using viral gene transfer. GABAergic silencing using Clozapine-N-Oxide (CNO) demonstrated reliable induction of local epileptiform events in the electroencephalogram signal of awake freely moving mice. Anesthetized mice experiments showed consistent induction of focal epileptiform-events in both the barrel cortex (BC) and the medial prefrontal cortex (mPFC), accompanied by high-frequency oscillations, a known characteristic of human seizures. Epileptiform-events showed propagation indication with favored propagation pathways: from the BC on 1 hemisphere to its counterpart and from the BC to the mPFC, but not vice-versa. Lastly, sensory whisker-pad stimulation evoked BC epileptiform events post-CNO, highlighting the potential use of this model in studying sensory-evoked seizures. Combined, our results show that targeted chemogenetic inhibition of GABAergic neurons using hM4D can serve as a novel, versatile, and reliable model of focal cortical epileptic activity suitable for systematically studying cortical ictogenesis in different cortical areas.
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Affiliation(s)
- Adi Miriam Goldenberg
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarah Schmidt
- Institute for Experimental Epileptology and Cognition Research, Life and Brain Center, University of Bonn, Bonn 53105, Germany
| | - Rea Mitelman
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Dana Rubi Levy
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Matthias Prigge
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yonatan Katz
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ofer Yizhar
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Heinz Beck
- Institute for Experimental Epileptology and Cognition Research, Life and Brain Center, University of Bonn, Bonn 53105, Germany
| | - Ilan Lampl
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
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19
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McFarlan AR, Chou CYC, Watanabe A, Cherepacha N, Haddad M, Owens H, Sjöström PJ. The plasticitome of cortical interneurons. Nat Rev Neurosci 2023; 24:80-97. [PMID: 36585520 DOI: 10.1038/s41583-022-00663-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2022] [Indexed: 12/31/2022]
Abstract
Hebb postulated that, to store information in the brain, assemblies of excitatory neurons coding for a percept are bound together via associative long-term synaptic plasticity. In this view, it is unclear what role, if any, is carried out by inhibitory interneurons. Indeed, some have argued that inhibitory interneurons are not plastic. Yet numerous recent studies have demonstrated that, similar to excitatory neurons, inhibitory interneurons also undergo long-term plasticity. Here, we discuss the many diverse forms of long-term plasticity that are found at inputs to and outputs from several types of cortical inhibitory interneuron, including their plasticity of intrinsic excitability and their homeostatic plasticity. We explain key plasticity terminology, highlight key interneuron plasticity mechanisms, extract overarching principles and point out implications for healthy brain functionality as well as for neuropathology. We introduce the concept of the plasticitome - the synaptic plasticity counterpart to the genome or the connectome - as well as nomenclature and definitions for dealing with this rich diversity of plasticity. We argue that the great diversity of interneuron plasticity rules is best understood at the circuit level, for example as a way of elucidating how the credit-assignment problem is solved in deep biological neural networks.
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Affiliation(s)
- Amanda R McFarlan
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
| | - Christina Y C Chou
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
| | - Airi Watanabe
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
| | - Nicole Cherepacha
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Maria Haddad
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
| | - Hannah Owens
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
| | - P Jesper Sjöström
- Centre for Research in Neuroscience, Department of Medicine, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
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20
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Trevelyan AJ, Graham RT, Parrish RR, Codadu NK. Synergistic Positive Feedback Mechanisms Underlying Seizure Initiation. Epilepsy Curr 2023; 23:38-43. [PMID: 36923333 PMCID: PMC10009126 DOI: 10.1177/15357597221127163] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Investigations into seizure initiation, in recent years, have focused almost entirely upon alterations of interneuronal function, chloride homeostasis, and extracellular potassium levels. In contrast, little attention has been directed toward a possible role of dendritic plateau potentials in the actual ictogenic transition, despite a substantial literature dating back 40 years regarding its importance generally in epilepsy. Here, we argue that an increase in dendritic excitability, coordinated across the population of pyramidal cells, is a key stage in ictogenesis.
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Affiliation(s)
- Andrew J. Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Robert T. Graham
- Queen Square Institute of Neurology, University College London, United Kingdom
| | - R. Ryley Parrish
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, USA
| | - Neela K. Codadu
- Queen Square Institute of Neurology, University College London, United Kingdom
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21
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Schuster J, Klar J, Khalfallah A, Laan L, Hoeber J, Fatima A, Sequeira VM, Jin Z, Korol SV, Huss M, Nordgren A, Anderlid BM, Gallant C, Birnir B, Dahl N. ZEB2 haploinsufficient Mowat-Wilson syndrome induced pluripotent stem cells show disrupted GABAergic transcriptional regulation and function. Front Mol Neurosci 2022; 15:988993. [PMID: 36353360 PMCID: PMC9637781 DOI: 10.3389/fnmol.2022.988993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/20/2022] [Indexed: 07/30/2023] Open
Abstract
Mowat-Wilson syndrome (MWS) is a severe neurodevelopmental disorder caused by heterozygous variants in the gene encoding transcription factor ZEB2. Affected individuals present with structural brain abnormalities, speech delay and epilepsy. In mice, conditional loss of Zeb2 causes hippocampal degeneration, altered migration and differentiation of GABAergic interneurons, a heterogeneous population of mainly inhibitory neurons of importance for maintaining normal excitability. To get insights into GABAergic development and function in MWS we investigated ZEB2 haploinsufficient induced pluripotent stem cells (iPSC) of MWS subjects together with iPSC of healthy donors. Analysis of RNA-sequencing data at two time points of GABAergic development revealed an attenuated interneuronal identity in MWS subject derived iPSC with enrichment of differentially expressed genes required for transcriptional regulation, cell fate transition and forebrain patterning. The ZEB2 haploinsufficient neural stem cells (NSCs) showed downregulation of genes required for ventral telencephalon specification, such as FOXG1, accompanied by an impaired migratory capacity. Further differentiation into GABAergic interneuronal cells uncovered upregulation of transcription factors promoting pallial and excitatory neurons whereas cortical markers were downregulated. The differentially expressed genes formed a neural protein-protein network with extensive connections to well-established epilepsy genes. Analysis of electrophysiological properties in ZEB2 haploinsufficient GABAergic cells revealed overt perturbations manifested as impaired firing of repeated action potentials. Our iPSC model of ZEB2 haploinsufficient GABAergic development thus uncovers a dysregulated gene network leading to immature interneurons with mixed identity and altered electrophysiological properties, suggesting mechanisms contributing to the neuropathogenesis and seizures in MWS.
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Affiliation(s)
- Jens Schuster
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Joakim Klar
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Ayda Khalfallah
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Loora Laan
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Jan Hoeber
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Ambrin Fatima
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Velin Marita Sequeira
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Zhe Jin
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Sergiy V. Korol
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Mikael Huss
- Wallenberg Long-Term Bioinformatics Support, Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Britt Marie Anderlid
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Caroline Gallant
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
| | - Bryndis Birnir
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Niklas Dahl
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden
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22
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Jing J, Dunbar C, Sonesra A, Chavez A, Park S, Yang R, Soh H, Lee M, Tzingounis AV, Cooper EC, Jiang X, Maheshwari A. Removal of KCNQ2 from parvalbumin-expressing interneurons improves anti-seizure efficacy of retigabine. Exp Neurol 2022; 355:114141. [PMID: 35691372 PMCID: PMC9899633 DOI: 10.1016/j.expneurol.2022.114141] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/18/2022] [Accepted: 06/06/2022] [Indexed: 02/07/2023]
Abstract
Anti-seizure drug (ASD) targets are widely expressed in both excitatory and inhibitory neurons. It remains unknown if the action of an ASD upon inhibitory neurons could counteract its beneficial effects on excitatory neurons (or vice versa), thereby reducing the efficacy of the ASD. Here, we examine whether the efficacy of the ASD retigabine (RTG) is altered after removal of the Kv7 potassium channel subunit KCNQ2, one of its drug targets, from parvalbumin-expressing interneurons (PV-INs). Parvalbumin-Cre (PV-Cre) mice were crossed with Kcnq2-floxed (Kcnq2fl/fl) mice to conditionally delete Kcnq2 from PV-INs. In these conditional knockout mice (cKO, PV-Kcnq2fl/fl), RTG (10 mg/kg, i.p.) significantly delayed the onset of either picrotoxin (PTX, 10 mg/kg, i.p)- or kainic acid (KA, 30 mg/kg, i.p.)-induced convulsive seizures compared to vehicle, while RTG was not effective in wild-type littermates (WT). Immunostaining for KCNQ2 and KCNQ3 revealed that both subunits were enriched at axon initial segments (AISs) of hippocampal CA1 PV-INs, and their specific expression was selectively abolished in cKO mice. Accordingly, the M-currents recorded from CA1 PV-INs and their sensitivity to RTG were significantly reduced in cKO mice. While the ability of RTG to suppress CA1 excitatory neurons in hippocampal slices was unchanged in cKO mice, its suppressive effect on the spike activity of CA1 PV-INs was significantly reduced compared with WT mice. In addition, the RTG-induced suppression on intrinsic membrane excitability of PV-INs in WT mice was significantly reduced in cKO mice. These findings suggest that preventing RTG from suppressing PV-INs improves its anticonvulsant effect.
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Affiliation(s)
- Junzhan Jing
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Street, Houston, TX 77030, United States of America
| | - Corrinne Dunbar
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Alina Sonesra
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Ana Chavez
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Suhyeorn Park
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Ryan Yang
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Rd, Storrs, CT 06269, United States of America
| | - Maxwell Lee
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Rd, Storrs, CT 06269, United States of America
| | - Edward C Cooper
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Street, Houston, TX 77030, United States of America.
| | - Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America.
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Automatic Detection and Classification of Epileptic Seizures in Patients with Liver Cirrhosis and Overlapping Hev Infection Based on Deep Multimodal Fusion Technology. CONTRAST MEDIA & MOLECULAR IMAGING 2022; 2022:3176134. [PMID: 36105452 PMCID: PMC9452993 DOI: 10.1155/2022/3176134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/27/2022] [Accepted: 08/06/2022] [Indexed: 11/17/2022]
Abstract
Liver cirrhosis is a clinical chronic developmental liver disease, which is caused by long-term or repeated effects of liver dysfunction, and there are more and more cases of epileptic seizures in patients with liver cirrhosis and HEV infection. This article aims to study how to analyze epileptic seizures in patients with liver cirrhosis and overlapping HEV infection based on deep multimodal fusion technology. This article proposes a deep learning neural network algorithm based on deep multimodal fusion technology, and how to use this algorithm to automatically detect and classify epileptic seizures. The data in the experiment in this article show that the prevalence of epilepsy accounts for 1% of the world's population, about 56.7 million people, and 1 in 25 people may have an epileptic seizure at some time in their lives, and in each person's life, the probability of seizures due to various reasons is 10%. In 2016, the proportion of males with cirrhosis reached 16%, females reached 8%, and males were 8% higher than females, which is a full double. The test results show that with the increase in patients with cirrhosis and overlapping HEV infection, the frequency of epileptic seizures is also getting higher and higher, indicating that the frequency of epileptic seizures has been increased in patients with cirrhosis and overlapping HEV infection. Therefore, it is imperative to analyze the epileptic seizures of patients with liver cirrhosis and overlapping HEV infection based on deep multimodal fusion technology.
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Pharmacological perspectives and mechanisms involved in epileptogenesis. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2022. [DOI: 10.1186/s43088-022-00278-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Epileptogenesis can be defined as the process by which a previously healthy brain develops a tendency toward recurrent electrical activity, occurring in three phases: first as an initial trigger (such as stroke, infections, and traumatic brain injury); followed by the latency period and the onset of spontaneous and recurrent seizures which characterizes epilepsy.
Main body
The mechanisms that may be involved in epileptogenesis are inflammation, neurogenesis, migration of neurons to different regions of the brain, neural reorganization, and neuroplasticity.In recent years, experimental studies have enabled the discovery of several mechanisms involved in the process of epileptogenesis, mainly neuroinflammation, that involves the activation of glial cells and an increase in specific inflammatory mediators. The lack of an experimental animal model protocol for epileptogenic compounds contributes to the difficulty in understanding disease development and the creation of new drugs.
Conclusion
To solve these difficulties, a new approach is needed in the development of new AEDs that focus on the process of epileptogenesis and the consolidation of animal models for studies of antiepileptogenic compounds, aiming to reach the clinical phases of the study. Some examples of these compounds are rapamycin, which inhibits mTOR signaling, and losartan, that potentiates the antiepileptogenic effect of some AEDs. Based on this, this review discusses the main mechanisms involved in epileptogenesis, as well as its pharmacological approach.
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Lévesque M, Wang S, Etter G, Williams S, Avoli M. Bilateral optogenetic activation of inhibitory cells favors ictogenesis. Neurobiol Dis 2022; 171:105794. [PMID: 35718264 DOI: 10.1016/j.nbd.2022.105794] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/10/2022] [Accepted: 06/12/2022] [Indexed: 11/26/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common type of focal refractory epilepsy and is characterized by recurring seizures that are often refractory to medication. Since parvalbumin-positive (PV) interneurons were recently shown to play significant roles in ictogenesis, we established here how bilateral optogenetic stimulation of these interneurons in the hippocampus CA3 regions modulates seizures, interictal spikes and high-frequency oscillations (HFOs; ripples: 80-200 Hz, fast ripples: 250-500 Hz) in the pilocarpine model of MTLE. Bilateral optogenetic stimulation of CA3 PV-positive interneurons at 8 Hz (lasting 30 s, every 2 min) was implemented in PV-ChR2 mice for 8 consecutive days starting on day 7 (n = 8) or on day 13 (n = 6) after pilocarpine-induced status epilepticus (SE). Seizure occurrence was higher in both day 7 and day 13 groups of PV-ChR2 mice during periods of optogenetic stimulation ("ON"), compared to when stimulation was not performed ("OFF") (day 7 group = p < 0.01, day 13 group = p < 0.01). In the PV-ChR2 day 13 group, rates of seizures (p < 0.05), of interictal spikes associated with fast ripples (p < 0.01), and of isolated fast ripples (p < 0.01) during optogenetic stimulations were significantly higher than in the PV-ChR2 day 7 group. Our findings reveal that bilateral activation of PV-interneurons in the hippocampus (leading to a presumptive increase in GABA signaling) favors ictogenesis. These effects may also mirror the neuropathological changes that occur over time after SE in this animal model.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, and of Physiology, McGill University, 3801 University Street, Montréal, H3A 2B4, QC, Canada
| | - Siyan Wang
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, and of Physiology, McGill University, 3801 University Street, Montréal, H3A 2B4, QC, Canada
| | - Guillaume Etter
- Douglas Mental Health University Institute, McGill University, 6875 Blvd Lasalle, Montréal, H4H 1R3, QC, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, 6875 Blvd Lasalle, Montréal, H4H 1R3, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, and of Physiology, McGill University, 3801 University Street, Montréal, H3A 2B4, QC, Canada.
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26
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Malwade S, Gasthaus J, Bellardita C, Andelic M, Moric B, Korshunova I, Kiehn O, Vasistha NA, Khodosevich K. Identification of Vulnerable Interneuron Subtypes in 15q13.3 Microdeletion Syndrome Using Single-Cell Transcriptomics. Biol Psychiatry 2022; 91:727-739. [PMID: 34838304 DOI: 10.1016/j.biopsych.2021.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/02/2022]
Abstract
BACKGROUND A number of rare copy number variants (CNVs) have been linked to neurodevelopmental disorders. However, because CNVs encompass many genes, it is often difficult to identify the mechanisms that lead to developmental perturbations. METHODS We used 15q13.3 microdeletion to propose and validate a novel strategy to predict the impact of CNV genes on brain development that could further guide functional studies. We analyzed single-cell transcriptomics datasets containing cortical interneurons to identify their developmental vulnerability to 15q13.3 microdeletion, which was validated in mouse models. RESULTS We found that Klf13-but not other 15q13.3 genes-is expressed by precursors and neuroblasts in the medial and caudal ganglionic eminences during development, with a peak of expression at embryonic day (E)13.5 and E18.5, respectively. In contrast, in the adult mouse brain, Klf13 expression is negligible. Using Df(h15q13.3)/+ and Klf13+/- embryos, we observed a precursor subtype-specific impairment in proliferation in the medial ganglionic eminence and caudal ganglionic eminence at E13.5 and E17.5, respectively, corresponding to vulnerability predicted by Klf13 expression patterns. Finally, Klf13+/- mice showed a layer-specific decrease in parvalbumin and somatostatin cortical interneurons accompanied by changes in locomotor and anxiety-related behavior. CONCLUSIONS We show that the impact of 15q13.3 microdeletion on precursor proliferation is grounded in a reduction in Klf13 expression. The lack of Klf13 in Df(h15q13.3)/+ cortex might be the major reason for perturbed density of cortical interneurons. Thus, the behavioral defects seen in 15q13.3 microdeletion could stem from a developmental perturbation owing to selective vulnerability of cortical interneurons during sensitive stages of their development.
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Affiliation(s)
- Susmita Malwade
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Janina Gasthaus
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Carmelo Bellardita
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matej Andelic
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Borna Moric
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Irina Korshunova
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ole Kiehn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Navneet A Vasistha
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Konstantin Khodosevich
- Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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27
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Lado WE, Xu X, Hablitz JJ. Modulation of Epileptiform Activity by Three Subgroups of GABAergic Interneurons in Mouse Somatosensory Cortex. Epilepsy Res 2022; 183:106937. [DOI: 10.1016/j.eplepsyres.2022.106937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/05/2022] [Accepted: 04/24/2022] [Indexed: 11/29/2022]
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28
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Mattis J, Somarowthu A, Goff KM, Jiang E, Yom J, Sotuyo N, Mcgarry LM, Feng H, Kaneko K, Goldberg EM. Corticohippocampal circuit dysfunction in a mouse model of Dravet syndrome. eLife 2022; 11:e69293. [PMID: 35212623 PMCID: PMC8920506 DOI: 10.7554/elife.69293] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 02/24/2022] [Indexed: 11/13/2022] Open
Abstract
Dravet syndrome (DS) is a neurodevelopmental disorder due to pathogenic variants in SCN1A encoding the Nav1.1 sodium channel subunit, characterized by treatment-resistant epilepsy, temperature-sensitive seizures, developmental delay/intellectual disability with features of autism spectrum disorder, and increased risk of sudden death. Convergent data suggest hippocampal dentate gyrus (DG) pathology in DS (Scn1a+/-) mice. We performed two-photon calcium imaging in brain slice to uncover a profound dysfunction of filtering of perforant path input by DG in young adult Scn1a+/- mice. This was not due to dysfunction of DG parvalbumin inhibitory interneurons (PV-INs), which were only mildly impaired at this timepoint; however, we identified enhanced excitatory input to granule cells, suggesting that circuit dysfunction is due to excessive excitation rather than impaired inhibition. We confirmed that both optogenetic stimulation of entorhinal cortex and selective chemogenetic inhibition of DG PV-INs lowered seizure threshold in vivo in young adult Scn1a+/- mice. Optogenetic activation of PV-INs, on the other hand, normalized evoked responses in granule cells in vitro. These results establish the corticohippocampal circuit as a key locus of pathology in Scn1a+/- mice and suggest that PV-INs retain powerful inhibitory function and may be harnessed as a potential therapeutic approach toward seizure modulation.
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Affiliation(s)
- Joanna Mattis
- Department of Neurology, The Perelman School of Medicine at The University of PennsylvaniaPhiladelphiaUnited States
| | - Ala Somarowthu
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Kevin M Goff
- Neuroscience Graduate Group, The University of Pennsylvania Perelman School of MedicinePhiladelphiaUnited States
| | - Evan Jiang
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Jina Yom
- College of Arts and Sciences, The University of PennsylvaniaPhiladelphiaUnited States
| | - Nathaniel Sotuyo
- Neuroscience Graduate Group, The University of Pennsylvania Perelman School of MedicinePhiladelphiaUnited States
| | - Laura M Mcgarry
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Huijie Feng
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Keisuke Kaneko
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Ethan M Goldberg
- Department of Neurology, The Perelman School of Medicine at The University of PennsylvaniaPhiladelphiaUnited States
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
- Department of Neuroscience, The Perelman School of Medicine at The University of PennsylvaniaPhiladelphiaUnited States
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29
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Niemeyer JE, Gadamsetty P, Chun C, Sylvester S, Lucas JP, Ma H, Schwartz TH, Aksay ERF. Seizures initiate in zones of relative hyperexcitation in a zebrafish epilepsy model. Brain 2022; 145:2347-2360. [PMID: 35196385 DOI: 10.1093/brain/awac073] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 11/12/2022] Open
Abstract
Seizures are thought to arise from an imbalance of excitatory and inhibitory neuronal activity. While most classical studies suggest excessive excitatory neural activity plays a generative role, some recent findings challenge this view and instead argue that excessive activity in inhibitory neurons initiates seizures. We investigated this question of imbalance in a zebrafish seizure model with two-photon imaging of excitatory and inhibitory neuronal activity throughout the brain using a nuclear-localized calcium sensor. We found that seizures consistently initiated in circumscribed zones of the midbrain before propagating to other brain regions. Excitatory neurons were both more prevalent and more likely to be recruited than inhibitory neurons in initiation as compared with propagation zones. These findings support a mechanistic picture whereby seizures initiate in a region of hyper-excitation, then propagate more broadly once inhibitory restraint in the surround is overcome.
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Affiliation(s)
- James E Niemeyer
- Department of Neurological Surgery, Weill Cornell Medicine, New York, NY 10065, USA.,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Poornima Gadamsetty
- Department of Neurological Surgery, Weill Cornell Medicine, New York, NY 10065, USA
| | - Chanwoo Chun
- Institute for Computational Biomedicine and the Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Sherika Sylvester
- Institute for Computational Biomedicine and the Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Jacob P Lucas
- Department of Neurological Surgery, Weill Cornell Medicine, New York, NY 10065, USA
| | - Hongtao Ma
- Department of Neurological Surgery, Weill Cornell Medicine, New York, NY 10065, USA.,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Theodore H Schwartz
- Department of Neurological Surgery, Weill Cornell Medicine, New York, NY 10065, USA.,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Emre R F Aksay
- Institute for Computational Biomedicine and the Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
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30
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Godoy LD, Prizon T, Rossignoli MT, Leite JP, Liberato JL. Parvalbumin Role in Epilepsy and Psychiatric Comorbidities: From Mechanism to Intervention. Front Integr Neurosci 2022; 16:765324. [PMID: 35250498 PMCID: PMC8891758 DOI: 10.3389/fnint.2022.765324] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
Parvalbumin is a calcium-binding protein present in inhibitory interneurons that play an essential role in regulating many physiological processes, such as intracellular signaling and synaptic transmission. Changes in parvalbumin expression are deeply related to epilepsy, which is considered one of the most disabling neuropathologies. Epilepsy is a complex multi-factor group of disorders characterized by periods of hypersynchronous activity and hyperexcitability within brain networks. In this scenario, inhibitory neurotransmission dysfunction in modulating excitatory transmission related to the loss of subsets of parvalbumin-expressing inhibitory interneuron may have a prominent role in disrupted excitability. Some studies also reported that parvalbumin-positive interneurons altered function might contribute to psychiatric comorbidities associated with epilepsy, such as depression, anxiety, and psychosis. Understanding the epileptogenic process and comorbidities associated with epilepsy have significantly advanced through preclinical and clinical investigation. In this review, evidence from parvalbumin altered function in epilepsy and associated psychiatric comorbidities were explored with a translational perspective. Some advances in potential therapeutic interventions are highlighted, from current antiepileptic and neuroprotective drugs to cutting edge modulation of parvalbumin subpopulations using optogenetics, designer receptors exclusively activated by designer drugs (DREADD) techniques, transcranial magnetic stimulation, genome engineering, and cell grafting. Creating new perspectives on mechanisms and therapeutic strategies is valuable for understanding the pathophysiology of epilepsy and its psychiatric comorbidities and improving efficiency in clinical intervention.
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Affiliation(s)
- Lívea Dornela Godoy
- Department of Psychology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Tamiris Prizon
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Matheus Teixeira Rossignoli
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - João Pereira Leite
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- João Pereira Leite,
| | - José Luiz Liberato
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- *Correspondence: José Luiz Liberato,
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31
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Wang Y, Wei P, Yan F, Luo Y, Zhao G. Animal Models of Epilepsy: A Phenotype-oriented Review. Aging Dis 2022; 13:215-231. [PMID: 35111370 PMCID: PMC8782545 DOI: 10.14336/ad.2021.0723] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/23/2021] [Indexed: 12/26/2022] Open
Abstract
Epilepsy is a serious neurological disorder characterized by abnormal, recurrent, and synchronous discharges in the brain. Long-term recurrent seizure attacks can cause serious damage to brain function, which is usually observed in patients with temporal lobe epilepsy. Controlling seizure attacks is vital for the treatment and prognosis of epilepsy. Animal models, such as the kindling model, which was the most widely used model in the past, allow the understanding of the potential epileptogenic mechanisms and selection of antiepileptic drugs. In recent years, various animal models of epilepsy have been established to mimic different seizure types, without clear merits and demerits. Accordingly, this review provides a summary of the views mentioned above, aiming to provide a reference for animal model selection.
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Affiliation(s)
- Yilin Wang
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Penghu Wei
- 1Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
| | - Feng Yan
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yumin Luo
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,3Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
| | - Guoguang Zhao
- 1Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China.,3Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
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32
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Cherubini E, Di Cristo G, Avoli M. Dysregulation of GABAergic Signaling in Neurodevelomental Disorders: Targeting Cation-Chloride Co-transporters to Re-establish a Proper E/I Balance. Front Cell Neurosci 2022; 15:813441. [PMID: 35069119 PMCID: PMC8766311 DOI: 10.3389/fncel.2021.813441] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/30/2021] [Indexed: 01/01/2023] Open
Abstract
The construction of the brain relies on a series of well-defined genetically and experience- or activity -dependent mechanisms which allow to adapt to the external environment. Disruption of these processes leads to neurological and psychiatric disorders, which in many cases are manifest already early in postnatal life. GABA, the main inhibitory neurotransmitter in the adult brain is one of the major players in the early assembly and formation of neuronal circuits. In the prenatal and immediate postnatal period GABA, acting on GABAA receptors, depolarizes and excites targeted cells via an outwardly directed flux of chloride. In this way it activates NMDA receptors and voltage-dependent calcium channels contributing, through intracellular calcium rise, to shape neuronal activity and to establish, through the formation of new synapses and elimination of others, adult neuronal circuits. The direction of GABAA-mediated neurotransmission (depolarizing or hyperpolarizing) depends on the intracellular levels of chloride [Cl−]i, which in turn are maintained by the activity of the cation-chloride importer and exporter KCC2 and NKCC1, respectively. Thus, the premature hyperpolarizing action of GABA or its persistent depolarizing effect beyond the postnatal period, leads to behavioral deficits associated with morphological alterations and an excitatory (E)/inhibitory (I) imbalance in selective brain areas. The aim of this review is to summarize recent data concerning the functional role of GABAergic transmission in building up and refining neuronal circuits early in development and its dysfunction in neurodevelopmental disorders such as Autism Spectrum Disorders (ASDs), schizophrenia and epilepsy. In particular, we focus on novel information concerning the mechanisms by which alterations in cation-chloride co-transporters (CCC) generate behavioral and cognitive impairment in these diseases. We discuss also the possibility to re-establish a proper GABAA-mediated neurotransmission and excitatory (E)/inhibitory (I) balance within selective brain areas acting on CCC.
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Affiliation(s)
- Enrico Cherubini
- European Brain Research Institute (EBRI)-Rita Levi-Montalcini, Roma, Italy
- *Correspondence: Enrico Cherubini
| | - Graziella Di Cristo
- Neurosciences Department, Université de Montréal and CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology and Neurosurgery and of Physiology, McGill University, Montreal, QC, Canada
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33
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Lillis KP. Imaging Interneuron Impairment in Ictogenesis: A Spatiotemporal Sweet Spot of Seizure Sampling in Scn1a+/. Epilepsy Curr 2021; 21:376-378. [PMID: 34924841 PMCID: PMC8655246 DOI: 10.1177/15357597211032045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Disrupting Epileptiform Activity by Preventing Parvalbumin Interneuron Depolarization Block. J Neurosci 2021; 41:9452-9465. [PMID: 34611025 DOI: 10.1523/jneurosci.1002-20.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 09/21/2021] [Accepted: 09/26/2021] [Indexed: 11/21/2022] Open
Abstract
Inhibitory synaptic mechanisms oppose epileptic network activity in the brain. The breakdown in this inhibitory restraint and propagation of seizure activity has been linked to the overwhelming of feedforward inhibition, which is provided in large part by parvalbumin-expressing (PV) interneurons in the cortex. The underlying cellular processes therefore represent potential targets for understanding and preventing the propagation of seizure activity. Here we use an optogenetic strategy to test the hypothesis that depolarization block in PV interneurons is a significant factor during the loss of inhibitory restraint. Depolarization block results from the inactivation of voltage-gated sodium channels and leads to impaired action potential firing. We used focal NMDA stimulation to elicit reproducible epileptiform discharges in hippocampal organotypic brain slices from male and female mice and combined this with targeted recordings from defined neuronal populations. Simultaneous patch-clamp recordings from PV interneurons and pyramidal neurons revealed epileptiform activity that was associated with an overwhelming of inhibitory synaptic mechanisms and the emergence of a partial, and then complete, depolarization block in PV interneurons. To counteract this depolarization block, we developed protocols for eliciting pulsed membrane hyperpolarization via the inhibitory opsin, archaerhodopsin. This optical approach was effective in counteracting cumulative inactivation of voltage-gated channels, maintaining PV interneuron action potential firing properties during the inhibitory restraint period, and reducing the probability of initiating epileptiform activity. These experiments support the idea that depolarization block is a point of weakness in feedforward inhibitory synaptic mechanisms and represents a target for preventing the initiation and spread of seizure activity.SIGNIFICANCE STATEMENT GABAA receptor-mediated synaptic transmission opposes seizure activity by establishing an inhibitory restraint against spreading excitation. Parvalbumin-expressing (PV) interneurons contribute significantly to this inhibitory restraint, but it has been suggested that these cells are overwhelmed as they enter a state of "depolarization block." Here we test the importance of this process by devising an optogenetic strategy to selectively relieve depolarization block in PV interneurons. By inducing brief membrane hyperpolarization, we show that it is possible to reduce depolarization block in PV interneurons, maintain their action potential firing in the face of strong excitation, and disrupt epileptiform activity in an in vitro model. This represents a proof of principle that targeting rate-limiting processes can strengthen the inhibitory restraint of epileptiform activity.
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35
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Dudok B, Klein PM, Soltesz I. Toward Understanding the Diverse Roles of Perisomatic Interneurons in Epilepsy. Epilepsy Curr 2021; 22:54-60. [PMID: 35233202 PMCID: PMC8832350 DOI: 10.1177/15357597211053687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Epileptic seizures are associated with excessive neuronal spiking. Perisomatic
γ-aminobutyric acid (GABA)ergic interneurons specifically innervate the subcellular
domains of postsynaptic excitatory cells that are critical for spike generation. With a
revolution in transcriptomics-based cell taxonomy driving the development of novel
transgenic mouse lines, selectively monitoring and modulating previously elusive
interneuron types is becoming increasingly feasible. Emerging evidence suggests that the
three types of hippocampal perisomatic interneurons, axo-axonic cells, along with
parvalbumin- and cholecystokinin-expressing basket cells, each follow unique activity
patterns in vivo, suggesting distinctive roles in regulating epileptic networks.
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Affiliation(s)
- Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Peter M. Klein
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
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36
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Cheng L, Xing Y, Zhang H, Liu R, Lai H, Piao Y, Wang W, Yan X, Li X, Wang J, Li D, Loh HH, Yu T, Zhang G, Yang X. Mechanistic Analysis of Micro-Neurocircuits Underlying the Epileptogenic Zone in Focal Cortical Dysplasia Patients. Cereb Cortex 2021; 32:2216-2230. [PMID: 34664065 DOI: 10.1093/cercor/bhab350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
We aim to explore the microscopic neurophysiology of focal cortical dysplasia (FCD) induced epileptogenesis in specific macroscopic brain regions, therefore mapping a micro-macro neuronal network that potentially indicates the epileptogenic mechanism. Epileptic and relatively non-epileptic temporal neocortex specimens were resected from FCD and mesial temporal lobe epilepsy (mTLE) patients, respectively. Whole-cell patch-clamping was performed on cells from the seizure onset zone (SOZ) and non-SOZ inside the epileptogenic zone (EZ) of FCD patients, as well as the non-epileptic neocortex of mTLE patients. Microscopic data were recorded, including membrane characteristics, spontaneous synaptic activities, and evoked action potentials. Immunohistochemistry was also performed on parvalbumin-positive (PV+) interneurons. We found that SOZ interneurons exhibited abnormal neuronal expression and distribution as well as reduced overall function compared with non-SOZ and mTLE interneurons. The SOZ pyramidal cells experienced higher excitation but lower inhibition than the mTLE controls, whereas the non-SOZ pyramidal cells exhibited intermediate excitability. Action potential properties of both types of neurons also suggested more synchronized neuronal activity inside the EZ, particularly inside the SOZ. Together, our research provides evidence for a potential neurocircuit underlying SOZ epileptogenesis and non-SOZ seizure susceptibility. Further investigation of this microscopic network may promote understanding of the mechanism of FCD-induced epileptogenesis.
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Affiliation(s)
- Lipeng Cheng
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Yue Xing
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Herui Zhang
- Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China
| | - Ru Liu
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Huanling Lai
- Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China
| | - Yueshan Piao
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Wei Wang
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xiaoming Yan
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xiaonan Li
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Jiaoyang Wang
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Donghong Li
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.,Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong 510635, China
| | - Horace H Loh
- Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China
| | - Tao Yu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Guojun Zhang
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.,Functional Neurosurgery Department, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China
| | - Xiaofeng Yang
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
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37
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Razak KA, Binder DK, Ethell IM. Neural Correlates of Auditory Hypersensitivity in Fragile X Syndrome. Front Psychiatry 2021; 12:720752. [PMID: 34690832 PMCID: PMC8529206 DOI: 10.3389/fpsyt.2021.720752] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/16/2021] [Indexed: 01/20/2023] Open
Abstract
The mechanisms underlying the common association between autism spectrum disorders (ASD) and sensory processing disorders (SPD) are unclear, and treatment options to reduce atypical sensory processing are limited. Fragile X Syndrome (FXS) is a leading genetic cause of intellectual disability and ASD behaviors. As in most children with ASD, atypical sensory processing is a common symptom in FXS, frequently manifesting as sensory hypersensitivity. Auditory hypersensitivity is a highly debilitating condition in FXS that may lead to language delays, social anxiety and ritualized repetitive behaviors. Animal models of FXS, including Fmr1 knock out (KO) mouse, also show auditory hypersensitivity, providing a translation relevant platform to study underlying pathophysiological mechanisms. The focus of this review is to summarize recent studies in the Fmr1 KO mouse that identified neural correlates of auditory hypersensitivity. We review results of electroencephalography (EEG) recordings in the Fmr1 KO mice and highlight EEG phenotypes that are remarkably similar to EEG findings in humans with FXS. The EEG phenotypes associated with the loss of FMRP include enhanced resting EEG gamma band power, reduced cross frequency coupling, reduced sound-evoked synchrony of neural responses at gamma band frequencies, increased event-related potential amplitudes, reduced habituation of neural responses and increased non-phase locked power. In addition, we highlight the postnatal period when the EEG phenotypes develop and show a strong association of the phenotypes with enhanced matrix-metalloproteinase-9 (MMP-9) activity, abnormal development of parvalbumin (PV)-expressing inhibitory interneurons and reduced formation of specialized extracellular matrix structures called perineuronal nets (PNNs). Finally, we discuss how dysfunctions of inhibitory PV interneurons may contribute to cortical hyperexcitability and EEG abnormalities observed in FXS. Taken together, the studies reviewed here indicate that EEG recordings can be utilized in both pre-clinical studies and clinical trials, while at the same time, used to identify cellular and circuit mechanisms of dysfunction in FXS. New therapeutic approaches that reduce MMP-9 activity and restore functions of PV interneurons may succeed in reducing FXS sensory symptoms. Future studies should examine long-lasting benefits of developmental vs. adult interventions on sensory phenotypes.
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Affiliation(s)
- Khaleel A. Razak
- Department of Psychology, University of California, Riverside, Riverside, CA, United States
- Graduate Neuroscience Program, University of California, Riverside, Riverside, CA, United States
| | - Devin K. Binder
- Graduate Neuroscience Program, University of California, Riverside, Riverside, CA, United States
- Division of Biomedical Sciences and Graduate Biomedical Sciences Program, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Iryna M. Ethell
- Graduate Neuroscience Program, University of California, Riverside, Riverside, CA, United States
- Division of Biomedical Sciences and Graduate Biomedical Sciences Program, School of Medicine, University of California, Riverside, Riverside, CA, United States
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38
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39
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Climer JR, Dombeck DA. Information Theoretic Approaches to Deciphering the Neural Code with Functional Fluorescence Imaging. eNeuro 2021; 8:ENEURO.0266-21.2021. [PMID: 34433574 PMCID: PMC8474651 DOI: 10.1523/eneuro.0266-21.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/22/2021] [Accepted: 08/04/2021] [Indexed: 11/21/2022] Open
Abstract
Information theoretic metrics have proven useful in quantifying the relationship between behaviorally relevant parameters and neuronal activity with relatively few assumptions. However, these metrics are typically applied to action potential (AP) recordings and were not designed for the slow timescales and variable amplitudes typical of functional fluorescence recordings (e.g., calcium imaging). The lack of research guidelines on how to apply and interpret these metrics with fluorescence traces means the neuroscience community has yet to realize the power of information theoretic metrics. Here, we used computational methods to create mock AP traces with known amounts of information. From these, we generated fluorescence traces and examined the ability of different information metrics to recover the known information values. We provide guidelines for how to use information metrics when applying them to functional fluorescence and demonstrate their appropriate application to GCaMP6f population recordings from mouse hippocampal neurons imaged during virtual navigation.
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Affiliation(s)
- Jason R Climer
- Department of Neurobiology, Northwestern University, Evanston, 60208 IL
| | - Daniel A Dombeck
- Department of Neurobiology, Northwestern University, Evanston, 60208 IL
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40
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Righes Marafiga J, Vendramin Pasquetti M, Calcagnotto ME. GABAergic interneurons in epilepsy: More than a simple change in inhibition. Epilepsy Behav 2021; 121:106935. [PMID: 32035792 DOI: 10.1016/j.yebeh.2020.106935] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/20/2022]
Abstract
The pathophysiology of epilepsy has been historically grounded on hyperexcitability attributed to the oversimplified imbalance between excitation (E) and inhibition (I) in the brain. The decreased inhibition is mostly attributed to deficits in gamma-aminobutyric acid-containing (GABAergic) interneurons, the main source of inhibition in the central nervous system. However, the cell diversity, the wide range of spatiotemporal connectivity, and the distinct effects of the neurotransmitter GABA especially during development, must be considered to critically revisit the concept of hyperexcitability caused by decreased inhibition as a key characteristic in the development of epilepsy. Here, we will discuss that behind this known mechanism, there is a heterogeneity of GABAergic interneurons with distinct functions and sources, which have specific roles in controlling the neural network activity within the recruited microcircuit and altered network during the epileptogenic process. This article is part of the Special Issue "NEWroscience 2018.
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Affiliation(s)
- Joseane Righes Marafiga
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil; Graduate Program in Biological Science: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil
| | - Mayara Vendramin Pasquetti
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil; Graduate Program in Biological Science: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil
| | - Maria Elisa Calcagnotto
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil; Graduate Program in Biological Science: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil; Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre 90046-900, RS, Brazil.
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41
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Karapinar R, Schwitalla JC, Eickelbeck D, Pakusch J, Mücher B, Grömmke M, Surdin T, Knöpfel T, Mark MD, Siveke I, Herlitze S. Reverse optogenetics of G protein signaling by zebrafish non-visual opsin Opn7b for synchronization of neuronal networks. Nat Commun 2021; 12:4488. [PMID: 34301944 PMCID: PMC8302595 DOI: 10.1038/s41467-021-24718-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 06/24/2021] [Indexed: 01/15/2023] Open
Abstract
Opn7b is a non-visual G protein-coupled receptor expressed in zebrafish. Here we find that Opn7b expressed in HEK cells constitutively activates the Gi/o pathway and illumination with blue/green light inactivates G protein-coupled inwardly rectifying potassium channels. This suggests that light acts as an inverse agonist for Opn7b and can be used as an optogenetic tool to inhibit neuronal networks in the dark and interrupt constitutive inhibition in the light. Consistent with this prediction, illumination of recombinant expressed Opn7b in cortical pyramidal cells results in increased neuronal activity. In awake mice, light stimulation of Opn7b expressed in pyramidal cells of somatosensory cortex reliably induces generalized epileptiform activity within a short (<10 s) delay after onset of stimulation. Our study demonstrates a reversed mechanism for G protein-coupled receptor control and Opn7b as a tool for controlling neural circuit properties.
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Affiliation(s)
- Raziye Karapinar
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
- Laboratory of Optogenetics and Circuit Neuroscience, Imperial College London, London, UK
- The Francis Crick Institute, London, UK
| | | | - Dennis Eickelbeck
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
- Laboratory of Optogenetics and Circuit Neuroscience, Imperial College London, London, UK
- The Francis Crick Institute, London, UK
| | - Johanna Pakusch
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Brix Mücher
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Michelle Grömmke
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Tatjana Surdin
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Thomas Knöpfel
- Laboratory of Optogenetics and Circuit Neuroscience, Imperial College London, London, UK
| | - Melanie D Mark
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany.
| | - Ida Siveke
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
- German Cancer Consortium (DKTK/DKFZ), West German Cancer Center, University Hospital Essen, Essen, Germany
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany.
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42
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An inventory of basic research in temporal lobe epilepsy. Rev Neurol (Paris) 2021; 177:1069-1081. [PMID: 34176659 DOI: 10.1016/j.neurol.2021.02.390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/26/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022]
Abstract
Temporal lobe epilepsy is a severe neurological disease, characterized by seizure occurrence and invalidating cognitive co-morbidities, which affects up to 1% of the adults. Roughly one third of the patients are resistant to any conventional pharmacological treatments. The last option in that case is the surgical removal of the epileptic focus, with no guarantee for clinical symptom alleviation. This state of affairs requests the identification of cellular or molecular targets for novel therapeutic approaches with limited side effects. Here we review some generalities about the disease as well as some of the most recent discoveries about the cellular and molecular mechanisms of TLE, and the latest perspectives for novel treatments.
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43
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Panthi S, Leitch B. Chemogenetic Activation of Feed-Forward Inhibitory Parvalbumin-Expressing Interneurons in the Cortico-Thalamocortical Network During Absence Seizures. Front Cell Neurosci 2021; 15:688905. [PMID: 34122016 PMCID: PMC8193234 DOI: 10.3389/fncel.2021.688905] [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: 03/31/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022] Open
Abstract
Parvalbumin-expressing (PV+) interneurons are a subset of GABAergic inhibitory interneurons that mediate feed-forward inhibition (FFI) within the cortico-thalamocortical (CTC) network of the brain. The CTC network is a reciprocal loop with connections between cortex and thalamus. FFI PV+ interneurons control the firing of principal excitatory neurons within the CTC network and prevent runaway excitation. Studies have shown that generalized spike-wave discharges (SWDs), the hallmark of absence seizures on electroencephalogram (EEG), originate within the CTC network. In the stargazer mouse model of absence epilepsy, reduced FFI is believed to contribute to absence seizure genesis as there is a specific loss of excitatory α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) at synaptic inputs to PV+ interneurons within the CTC network. However, the degree to which this deficit is directly related to seizure generation has not yet been established. Using chemogenetics and in vivo EEG recording, we recently demonstrated that functional silencing of PV+ interneurons in either the somatosensory cortex (SScortex) or the reticular thalamic nucleus (RTN) is sufficient to generate absence-SWDs. Here, we used the same approach to assess whether activating PV+ FFI interneurons within the CTC network during absence seizures would prevent or reduce seizures. To target these interneurons, mice expressing Cre recombinase in PV+ interneurons (PV-Cre) were bred with mice expressing excitatory Gq-DREADD (hM3Dq-flox) receptors. An intraperitoneal dose of pro-epileptic chemical pentylenetetrazol (PTZ) was used to induce absence seizure. The impact of activation of FFI PV+ interneurons during seizures was tested by focal injection of the “designer drug” clozapine N-oxide (CNO) into either the SScortex or the RTN thalamus. Seizures were assessed in PVCre/Gq-DREADD animals using EEG/video recordings. Overall, DREADD-mediated activation of PV+ interneurons provided anti-epileptic effects against PTZ-induced seizures. CNO activation of FFI either prevented PTZ-induced absence seizures or suppressed their severity. Furthermore, PTZ-induced tonic-clonic seizures were also reduced in severity by activation of FFI PV+ interneurons. In contrast, administration of CNO to non-DREADD wild-type control animals did not afford any protection against PTZ-induced seizures. These data demonstrate that FFI PV+ interneurons within CTC microcircuits could be a potential therapeutic target for anti-absence seizure treatment in some patients.
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Affiliation(s)
- Sandesh Panthi
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Beulah Leitch
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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44
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Lim HK, You N, Bae S, Kang BM, Shon YM, Kim SG, Suh M. Differential contribution of excitatory and inhibitory neurons in shaping neurovascular coupling in different epileptic neural states. J Cereb Blood Flow Metab 2021; 41:1145-1161. [PMID: 32669018 PMCID: PMC8054729 DOI: 10.1177/0271678x20934071] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Understanding the neurovascular coupling (NVC) underlying hemodynamic changes in epilepsy is crucial to properly interpreting functional brain imaging signals associated with epileptic events. However, how excitatory and inhibitory neurons affect vascular responses in different epileptic states remains unknown. We conducted real-time in vivo measurements of cerebral blood flow (CBF), vessel diameter, and excitatory and inhibitory neuronal calcium signals during recurrent focal seizures. During preictal states, decreases in CBF and arteriole diameter were closely related to decreased γ-band local field potential (LFP) power, which was linked to relatively elevated excitatory and reduced inhibitory neuronal activity levels. Notably, this preictal condition was followed by a strengthened ictal event. In particular, the preictal inhibitory activity level was positively correlated with coherent oscillating activity specific to inhibitory neurons. In contrast, ictal states were characterized by elevated synchrony in excitatory neurons. Given these findings, we suggest that excitatory and inhibitory neurons differentially contribute to shaping the ictal and preictal neural states, respectively. Moreover, the preictal vascular activity, alongside with the γ-band, may reflect the relative levels of excitatory and inhibitory neuronal activity, and upcoming ictal activity. Our findings provide useful insights into how perfusion signals of different epileptic states are related in terms of NVC.
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Affiliation(s)
- Hyun-Kyoung Lim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biological Sciences, Sungkyunkwan University, Suwon, South Korea
| | - Nayeon You
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Sungjun Bae
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Bok-Man Kang
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Young-Min Shon
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Minah Suh
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, South Korea.,Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Suwon, South Korea
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45
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Karoly PJ, Rao VR, Gregg NM, Worrell GA, Bernard C, Cook MJ, Baud MO. Cycles in epilepsy. Nat Rev Neurol 2021; 17:267-284. [PMID: 33723459 DOI: 10.1038/s41582-021-00464-1] [Citation(s) in RCA: 115] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2021] [Indexed: 01/31/2023]
Abstract
Epilepsy is among the most dynamic disorders in neurology. A canonical view holds that seizures, the characteristic sign of epilepsy, occur at random, but, for centuries, humans have looked for patterns of temporal organization in seizure occurrence. Observations that seizures are cyclical date back to antiquity, but recent technological advances have, for the first time, enabled cycles of seizure occurrence to be quantitatively characterized with direct brain recordings. Chronic recordings of brain activity in humans and in animals have yielded converging evidence for the existence of cycles of epileptic brain activity that operate over diverse timescales: daily (circadian), multi-day (multidien) and yearly (circannual). Here, we review this evidence, synthesizing data from historical observational studies, modern implanted devices, electronic seizure diaries and laboratory-based animal neurophysiology. We discuss advances in our understanding of the mechanistic underpinnings of these cycles and highlight the knowledge gaps that remain. The potential clinical applications of a knowledge of cycles in epilepsy, including seizure forecasting and chronotherapy, are discussed in the context of the emerging concept of seizure risk. In essence, this Review addresses the broad question of why seizures occur when they occur.
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Affiliation(s)
- Philippa J Karoly
- Graeme Clark Institute, The University of Melbourne, Melbourne, Victoria, Australia.
| | - Vikram R Rao
- Department of Neurology, University of California, San Francisco, CA, USA.,Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
| | - Nicholas M Gregg
- Bioelectronics, Neurophysiology and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Gregory A Worrell
- Bioelectronics, Neurophysiology and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Christophe Bernard
- Aix Marseille University, Inserm, Institut de Neurosciences des Systèmes, Marseille, France
| | - Mark J Cook
- Graeme Clark Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Maxime O Baud
- Sleep-Wake-Epilepsy Center, Department of Neurology, Inselspital Bern, University Hospital, University of Bern, Bern, Switzerland. .,Center for Experimental Neurology, Department of Neurology, Inselspital Bern, University Hospital, University of Bern, Bern, Switzerland.
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46
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Interneuron Dysfunction in a New Mouse Model of SCN1A GEFS. eNeuro 2021; 8:ENEURO.0394-20.2021. [PMID: 33658306 PMCID: PMC8174035 DOI: 10.1523/eneuro.0394-20.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 11/21/2022] Open
Abstract
Advances in genome sequencing have identified over 1300 mutations in the SCN1A sodium channel gene that result in genetic epilepsies. However, it still remains unclear how most individual mutations within SCN1A result in seizures. A previous study has shown that the K1270T (KT) mutation, linked to genetic epilepsy with febrile seizure plus (GEFS+) in humans, causes heat-induced seizure activity associated with a temperature-dependent decrease in GABAergic neuron excitability in a Drosophila knock-in model. To examine the behavioral and cellular effects of this mutation in mammals, we introduced the equivalent KT mutation into the mouse (Mus musculus) Scn1a (Scn1aKT) gene using CRISPR/Cas9 and generated mutant lines in two widely used genetic backgrounds: C57BL/6NJ and 129X1/SvJ. In both backgrounds, mice homozygous for the KT mutation had spontaneous seizures and died by postnatal day (P)23. There was no difference in mortality of heterozygous KT mice compared with wild-type littermates up to six months old. Heterozygous mutants exhibited heat-induced seizures at ∼42°C, a temperature that did not induce seizures in wild-type littermates. In acute hippocampal slices at permissive temperatures, current-clamp recordings revealed a significantly depolarized shift in action potential threshold and reduced action potential amplitude in parvalbumin (PV)-expressing inhibitory CA1 interneurons in Scn1aKT/+ mice. There was no change in the firing properties of excitatory CA1 pyramidal neurons. These results suggest that a constitutive decrease in inhibitory interneuron excitability contributes to the seizure phenotype in the mouse model.
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47
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Ryu B, Nagappan S, Santos-Valencia F, Lee P, Rodriguez E, Lackie M, Takatoh J, Franks KM. Chronic loss of inhibition in piriform cortex following brief, daily optogenetic stimulation. Cell Rep 2021; 35:109001. [PMID: 33882304 PMCID: PMC8102022 DOI: 10.1016/j.celrep.2021.109001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 12/10/2020] [Accepted: 03/24/2021] [Indexed: 12/02/2022] Open
Abstract
It is well established that seizures beget seizures, yet the cellular processes that underlie progressive epileptogenesis remain unclear. Here, we use optogenetics to briefly activate targeted populations of mouse piriform cortex (PCx) principal neurons in vivo. After just 3 or 4 days of stimulation, previously subconvulsive stimuli trigger massive, generalized seizures. Highly recurrent allocortices are especially prone to “optokindling.” Optokindling upsets the balance of recurrent excitation and feedback inhibition. To understand how this balance is disrupted, we then selectively reactivate the same neurons in vitro. Surprisingly, we find no evidence of heterosynaptic potentiation; instead, we observe a marked, pathway-specific decrease in feedback inhibition. We find no loss of inhibitory interneurons; rather, decreased GABA synthesis in feedback inhibitory neurons appears to underlie weakened inhibition. Optokindling will allow precise identification of the molecular processes by which brain activity patterns can progressively and pathologically disrupt the balance of cortical excitation and inhibition. Ryu et al. use optogenetics to briefly activate principal neurons in mouse piriform cortex. After 4 days, previously innocuous stimuli evoke massive, generalized seizures. “Optokindling” does not strengthen recurrent excitation; instead, it weakens feedback inhibition by decreasing synaptic cleft GABA concentrations and slowing vesicle refilling, consistent with decreased GABA synthesis.
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Affiliation(s)
- Brendan Ryu
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | | | | | - Psyche Lee
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Erica Rodriguez
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Meredith Lackie
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Jun Takatoh
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Kevin M Franks
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA.
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48
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Duffy BA, Choy M, Lee JH. Predicting Successful Generation and Inhibition of Seizure-like Afterdischarges and Mapping Their Seizure Networks Using fMRI. Cell Rep 2021; 30:2540-2554.e4. [PMID: 32101734 DOI: 10.1016/j.celrep.2020.01.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 12/18/2019] [Accepted: 01/27/2020] [Indexed: 11/30/2022] Open
Abstract
To understand the conditions necessary to initiate and terminate seizures, we investigate optogenetically induced hippocampal seizures with LFP, fMRI, and optogenetic inhibition. During afterdischarge induction using optogenetics, LFP recordings show that stimulations with earlier ictal onset times are more likely to result in afterdischarges and are more difficult to curtail with optogenetic inhibition. These results are generalizable across two initiation sites, the dorsal and ventral hippocampus. fMRI shows that afterdischarges initiated from the dorsal or ventral hippocampus exhibit distinct networks. Short-duration seizures initiated in the dorsal and ventral hippocampus are unilateral and bilateral, respectively, while longer-duration afterdischarges recruit broader, bilateral networks. When optogenetic inhibition is ineffective at stopping seizures, the network activity spreads more extensively but largely overlaps with the network activity associated with seizures that could be curtailed. These results provide insights into how seizures can be inhibited, which has implications for targeted seizure interventions.
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Affiliation(s)
- Ben A Duffy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - ManKin Choy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Jin Hyung Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
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49
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Rasia-Filho AA, Guerra KTK, Vásquez CE, Dall’Oglio A, Reberger R, Jung CR, Calcagnotto ME. The Subcortical-Allocortical- Neocortical continuum for the Emergence and Morphological Heterogeneity of Pyramidal Neurons in the Human Brain. Front Synaptic Neurosci 2021; 13:616607. [PMID: 33776739 PMCID: PMC7991104 DOI: 10.3389/fnsyn.2021.616607] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 02/01/2021] [Indexed: 11/13/2022] Open
Abstract
Human cortical and subcortical areas integrate emotion, memory, and cognition when interpreting various environmental stimuli for the elaboration of complex, evolved social behaviors. Pyramidal neurons occur in developed phylogenetic areas advancing along with the allocortex to represent 70-85% of the neocortical gray matter. Here, we illustrate and discuss morphological features of heterogeneous spiny pyramidal neurons emerging from specific amygdaloid nuclei, in CA3 and CA1 hippocampal regions, and in neocortical layers II/III and V of the anterolateral temporal lobe in humans. Three-dimensional images of Golgi-impregnated neurons were obtained using an algorithm for the visualization of the cell body, dendritic length, branching pattern, and pleomorphic dendritic spines, which are specialized plastic postsynaptic units for most excitatory inputs. We demonstrate the emergence and development of human pyramidal neurons in the cortical and basomedial (but not the medial, MeA) nuclei of the amygdala with cells showing a triangular cell body shape, basal branched dendrites, and a short apical shaft with proximal ramifications as "pyramidal-like" neurons. Basomedial neurons also have a long and distally ramified apical dendrite not oriented to the pial surface. These neurons are at the beginning of the allocortex and the limbic lobe. "Pyramidal-like" to "classic" pyramidal neurons with laminar organization advance from the CA3 to the CA1 hippocampal regions. These cells have basal and apical dendrites with specific receptive synaptic domains and several spines. Neocortical pyramidal neurons in layers II/III and V display heterogeneous dendritic branching patterns adapted to the space available and the afferent inputs of each brain area. Dendritic spines vary in their distribution, density, shapes, and sizes (classified as stubby/wide, thin, mushroom-like, ramified, transitional forms, "atypical" or complex forms, such as thorny excrescences in the MeA and CA3 hippocampal region). Spines were found isolated or intermingled, with evident particularities (e.g., an extraordinary density in long, deep CA1 pyramidal neurons), and some showing a spinule. We describe spiny pyramidal neurons considerably improving the connectional and processing complexity of the brain circuits. On the other hand, these cells have some vulnerabilities, as found in neurodegenerative Alzheimer's disease and in temporal lobe epilepsy.
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Affiliation(s)
- Alberto A. Rasia-Filho
- Department of Basic Sciences/Physiology and Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Kétlyn T. Knak Guerra
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carlos Escobar Vásquez
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Aline Dall’Oglio
- Department of Basic Sciences/Physiology and Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
| | - Roman Reberger
- Medical Engineering Program, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Cláudio R. Jung
- Institute of Informatics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Maria Elisa Calcagnotto
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry and Biochemistry Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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50
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Gao Y, Zheng J, Jiang T, Pi G, Sun F, Xiong R, Wang W, Wu D, Li S, Lei H, Yu H, Zhou Q, Yang Y, Zhang H, Wang JZ. Targeted Reducing of Tauopathy Alleviates Epileptic Seizures and Spatial Memory Impairment in an Optogenetically Inducible Mouse Model of Epilepsy. Front Cell Dev Biol 2021; 8:633725. [PMID: 33681188 PMCID: PMC7930339 DOI: 10.3389/fcell.2020.633725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/29/2020] [Indexed: 11/13/2022] Open
Abstract
Intracellular deposition of hyperphosphorylated tau has been reported in the brain of epilepsy patients, but its contribution to epileptic seizures and the association with spatial cognitive functions remain unclear. Here, we found that repeated optogenetic stimulation of the excitatory neurons in ventral hippocampal CA1 subset could induce a controllable epileptic seizure in mice. Simultaneously, the mice showed spatial learning and memory deficits with a prominently elevated total tau and phospho-tau levels in the brain. Importantly, selective facilitating tau degradation by using a novel designed proteolysis-targeting chimera named C4 could effectively ameliorate the epileptic seizures with remarkable restoration of neuronal firing activities and improvement of spatial learning and memory functions. These results confirm that abnormal tau accumulation plays a pivotal role in the epileptic seizures and the epilepsy-associated spatial memory impairments, which provides new molecular target for the therapeutics.
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Affiliation(s)
- Yang Gao
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Zheng
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Pharmacology, Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Tao Jiang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guilin Pi
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Sun
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Xiong
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weijin Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dongqin Wu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shihong Li
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiyang Lei
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiling Yu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiuzhi Zhou
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Yang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huaqiu Zhang
- Department of Neurosurgery, Key Laboratory of Ministry of Education for Neurological Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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