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Song H, Mah B, Sun Y, Aloysius N, Bai Y, Zhang L. Development of spontaneous recurrent seizures accompanied with increased rates of interictal spikes and decreased hippocampal delta and theta activities following extended kindling in mice. Exp Neurol 2024; 379:114860. [PMID: 38876195 DOI: 10.1016/j.expneurol.2024.114860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/30/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024]
Abstract
Interictal epileptiform discharges refer to aberrant brain electrographic signals between seizures and feature intermittent interictal spikes (ISs), sharp waves, and/or abnormal rhythms. Recognition of these epileptiform activities by electroencephalographic (EEG) examinations greatly aids epilepsy diagnosis and localization of the seizure onset zone. ISs are a major form of interictal epileptiform discharges recognized in animal models of epilepsy. Progressive changes in IS waveforms, IS rates, and/or associated fast ripple oscillations have been shown to precede the development of spontaneous recurrent seizures (SRS) in various animal models. IS expressions in the kindling model of epilepsy have been demonstrated but IS changes during the course of SRS development in extended kindled animals remain to be detailed. We hence addressed this issue using a mouse model of kindling-induced SRS. Adult C57 black mice received twice daily hippocampal stimulations until SRS occurrence, with 24-h EEG monitoring performed following 50, 80, and ≥ 100 stimulations and after observation of SRS. In the stimulated hippocampus, increases in spontaneous ISs rates, but not in IS waveforms nor IS-associated fast ripples, along with decreased frequencies of hippocampal delta and theta rhythms, were observed before SRS onset. Comparable increases in IS rates were further observed in the unstimulated hippocampus, piriform cortex, and entorhinal cortex, but not in the unstimulated parietal cortex and dorsomedial thalamus. These data provide original evidence suggesting that increases in hippocampal IS rates, together with reductions in hippocampal delta and theta rhythms are closely associated with development of SRS in a rodent kindling model.
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Affiliation(s)
- Hongmei Song
- Department of Neurosurgery, the First Hospital of Jilin University, China; Krembil Research Institute, University Health Network, Canada.
| | - Bryan Mah
- Krembil Research Institute, University Health Network, Canada
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Canada
| | - Nancy Aloysius
- Krembil Research Institute, University Health Network, Canada
| | - Yang Bai
- Department of Neuro-Oncology, the First Hospital of Jilin University, China.
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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2
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Dong L, Luan MY, Qi YN, Tian CX, Zheng Y. Calcium homeostasis restoration in pyramidal neurons through micrometer-scale wireless electrical stimulation in spinal cord injured mice. Biochem Biophys Res Commun 2024; 735:150487. [PMID: 39096885 DOI: 10.1016/j.bbrc.2024.150487] [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: 05/21/2024] [Revised: 07/19/2024] [Accepted: 07/31/2024] [Indexed: 08/05/2024]
Abstract
Spinal Cord Injury (SCI) is a significant neurological disorder that can result in severe motor and cognitive impairments. Neuronal regeneration and functional recovery are critical aspects of SCI treatment, with calcium signaling being a crucial indicator of neuronal excitability. In this study, we utilized a murine model to investigate the effects of targeted wireless electrical stimulation (ES) on neuronal activity following SCI. After establishing a complete SCI model in normal mice, flexible electrodes were implanted, and targeted wireless ES was administered to the injury site. We employed fiber-optic photometric in vivo calcium imaging to monitor calcium signals in pyramidal neurons within the CA3 region of the hippocampus and the M1 region of the primary motor cortex. The experimental results demonstrated a significant reduction in calcium signals in CA3 and M1 pyramidal neurons following SCI (reduced by 76 % and 59 %, in peak respectively). However, the application of targeted wireless ES led to a marked increase in calcium signals in these neurons (increased by 118 % and 69 %, in peak respectively), indicating a recovery of calcium activity. These observations suggest that wireless ES has a positive modulatory effect on the excitability of pyramidal neurons post-SCI. Understanding these mechanisms is crucial for developing therapeutic strategies aimed at enhancing neuronal recovery and functional restoration following spinal cord injuries.
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Affiliation(s)
- Lei Dong
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Meng-Ying Luan
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Ye-Nan Qi
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Chun-Xiao Tian
- School of Biomedical Engineering, Tianjin Medical University, Tianjin, 300203, China.
| | - Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin, 300387, China.
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3
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Guarino A, Pignata P, Lovisari F, Asth L, Simonato M, Soukupova M. Cognitive comorbidities in the rat pilocarpine model of epilepsy. Front Neurol 2024; 15:1392977. [PMID: 38872822 PMCID: PMC11171745 DOI: 10.3389/fneur.2024.1392977] [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: 02/28/2024] [Accepted: 04/30/2024] [Indexed: 06/15/2024] Open
Abstract
Patients with epilepsy are prone to cognitive decline, depression, anxiety and other behavioral disorders. Cognitive comorbidities are particularly common and well-characterized in people with temporal lobe epilepsy, while inconsistently addressed in epileptic animals. Therefore, the aim of this study was to ascertain whether there is good evidence of cognitive comorbidities in animal models of epilepsy, in particular in the rat pilocarpine model of temporal lobe epilepsy. We searched the literature published between 1990 and 2023. The association of spontaneous recurrent seizures induced by pilocarpine with cognitive alterations has been evaluated by using various tests: contextual fear conditioning (CFC), novel object recognition (NOR), radial and T-maze, Morris water maze (MWM) and their variants. Combination of results was difficult because of differences in methodological standards, in number of animals employed, and in outcome measures. Taken together, however, the analysis confirmed that pilocarpine-induced epilepsy has an effect on cognition in rats, and supports the notion that this is a valid model for assessment of cognitive temporal lobe epilepsy comorbidities in preclinical research.
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Affiliation(s)
- Annunziata Guarino
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Paola Pignata
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Francesca Lovisari
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Laila Asth
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Michele Simonato
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Marie Soukupova
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
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Feng Y, Diego KS, Dong Z, Wick ZC, Page-Harley L, Page-Harley V, Schnipper J, Lamsifer SI, Pennington ZT, Vetere LM, Philipsberg PA, Soler I, Jurkowski A, Rosado CJ, Khan NN, Cai DJ, Shuman T. Distinct changes to hippocampal and medial entorhinal circuits emerge across the progression of cognitive deficits in epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584697. [PMID: 38559224 PMCID: PMC10979962 DOI: 10.1101/2024.03.12.584697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Temporal lobe epilepsy (TLE) causes pervasive and progressive memory impairments, yet the specific circuit changes that drive these deficits remain unclear. To investigate how hippocampal-entorhinal dysfunction contributes to progressive memory deficits in epilepsy, we performed simultaneous in vivo electrophysiology in hippocampus (HPC) and medial entorhinal cortex (MEC) of control and epileptic mice 3 or 8 weeks after pilocarpine-induced status epilepticus (Pilo-SE). We found that HPC synchronization deficits (including reduced theta power, coherence, and altered interneuron spike timing) emerged within 3 weeks of Pilo-SE, aligning with early-onset, relatively subtle memory deficits. In contrast, abnormal synchronization within MEC and between HPC-MEC emerged later, by 8 weeks after Pilo-SE, when spatial memory impairment was more severe. Furthermore, a distinct subpopulation of MEC layer 3 excitatory neurons (active at theta troughs) was specifically impaired in epileptic mice. Together, these findings suggest that hippocampal-entorhinal circuit dysfunction accumulates and shifts as cognitive impairment progresses in TLE.
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Affiliation(s)
- Yu Feng
- Icahn School of Medicine at Mount Sinai, New York, NY
| | | | - Zhe Dong
- Icahn School of Medicine at Mount Sinai, New York, NY
| | | | | | | | | | | | | | | | | | - Ivan Soler
- Icahn School of Medicine at Mount Sinai, New York, NY
| | | | | | - Nadia N Khan
- Icahn School of Medicine at Mount Sinai, New York, NY
| | - Denise J Cai
- Icahn School of Medicine at Mount Sinai, New York, NY
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Luna-Munguia H, Gasca-Martinez D, Garay-Cortes A, Coutiño D, Regalado M, de Los Rios E, Villaseñor P, Hidalgo-Flores F, Flores-Guapo K, Benito BY, Concha L. Selective Medial Septum Lesions in Healthy Rats Induce Longitudinal Changes in Microstructure of Limbic Regions, Behavioral Alterations, and Increased Susceptibility to Status Epilepticus. Mol Neurobiol 2024:10.1007/s12035-024-04069-9. [PMID: 38443731 DOI: 10.1007/s12035-024-04069-9] [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: 09/25/2023] [Accepted: 02/26/2024] [Indexed: 03/07/2024]
Abstract
Septo-hippocampal pathway, crucial for physiological functions and involved in epilepsy. Clinical monitoring during epileptogenesis is complicated. We aim to evaluate tissue changes after lesioning the medial septum (MS) of normal rats and assess how the depletion of specific neuronal populations alters the animals' behavior and susceptibility to establishing a pilocarpine-induced status epilepticus. Male Sprague-Dawley rats were injected into the MS with vehicle or saporins (to deplete GABAergic or cholinergic neurons; n = 16 per group). Thirty-two animals were used for diffusion tensor imaging (DTI); scanned before surgery and 14 and 49 days post-injection. Fractional anisotropy and apparent diffusion coefficient were evaluated in the fimbria, dorsal hippocampus, ventral hippocampus, dorso-medial thalamus, and amygdala. Between scans 2 and 3, animals were submitted to diverse behavioral tasks. Stainings were used to analyze tissue alterations. Twenty-four different animals received pilocarpine to evaluate the latency and severity of the status epilepticus 2 weeks after surgery. Additionally, eight different animals were only used to evaluate the neuronal damage inflicted on the MS 1 week after the molecular surgery. Progressive changes in DTI parameters in both white and gray matter structures of the four evaluated groups were observed. Behaviorally, the GAT1-saporin injection impacted spatial memory formation, while 192-IgG-saporin triggered anxiety-like behaviors. Histologically, the GABAergic toxin also induced aberrant mossy fiber sprouting, tissue damage, and neuronal death. Regarding the pilocarpine-induced status epilepticus, this agent provoked an increased mortality rate. Selective septo-hippocampal modulation impacts the integrity of limbic regions crucial for certain behavioral skills and could represent a precursor for epilepsy development.
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Affiliation(s)
- Hiram Luna-Munguia
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico.
| | - Deisy Gasca-Martinez
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
- Unidad de Analisis Conductual, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Alejandra Garay-Cortes
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Daniela Coutiño
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Mirelta Regalado
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Ericka de Los Rios
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
- Unidad de Microscopia, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Paulina Villaseñor
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Fernando Hidalgo-Flores
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Karen Flores-Guapo
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Brandon Yair Benito
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Luis Concha
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
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He G, Li Y, Deng H, Zuo H. Advances in the study of cholinergic circuits in the central nervous system. Ann Clin Transl Neurol 2023; 10:2179-2191. [PMID: 37846148 PMCID: PMC10723250 DOI: 10.1002/acn3.51920] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023] Open
Abstract
OBJECTIVE Further understanding of the function and regulatory mechanism of cholinergic neural circuits and related neurodegenerative diseases. METHODS This review summarized the research progress of the central cholinergic nervous system, especially for the cholinergic circuit of the medial septal nucleus-hippocampus, vertical branch of diagonal band-hippocampus, basal nucleus of Meynert-cerebral cortex cholinergic loop, amygdala, pedunculopontine nucleus, and striatum-related cholinergic loops. RESULTS The extensive and complex fiber projection of cholinergic neurons form the cholinergic neural circuits, which regulate several nuclei in the brain through neurotransmission and participate in learning and memory, attention, emotion, movement, etc. The loss of cholinergic neurotransmitters, the reduction, loss, and degeneration of cholinergic neurons or abnormal theta oscillations and cholinergic neural circuits can induce cognitive disorders such as AD, PD, PDD, and DLB. INTERPRETATION The projection and function of cholinergic fibers in some nuclei and the precise regulatory mechanisms of cholinergic neural circuits in the brain remain unclear. Further investigation of cholinergic fiber projections in various brain regions and the underlying mechanisms of the neural circuits are expected to open up new avenues for the prevention and treatment of senile neurodegenerative diseases.
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Affiliation(s)
- Ganghua He
- Beijing Institute of Radiation MedicineBeijingChina
- College of Life Science and Engineering, Foshan UniversityFoshanChina
| | - Yang Li
- Beijing Institute of Radiation MedicineBeijingChina
| | - Hua Deng
- College of Life Science and Engineering, Foshan UniversityFoshanChina
| | - Hongyan Zuo
- Beijing Institute of Radiation MedicineBeijingChina
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Dyomina AV, Smolensky IV, Zaitsev AV. Refinement of the Barnes and Morris water maze protocols improves characterization of spatial cognitive deficits in the lithium-pilocarpine rat model of epilepsy. Epilepsy Behav 2023; 147:109391. [PMID: 37619464 DOI: 10.1016/j.yebeh.2023.109391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/26/2023]
Abstract
Temporal lobe epilepsy (TLE) often causes cognitive impairment, especially a decline in spatial memory. Reductions in spatial memory and learning are also common in rodent models of TLE. The Morris water maze and the Barnes maze are the standard methods for evaluating spatial learning and memory in rodents. However, animals with TLE may exhibit agitation, distress, and fail to follow the paradigmatic context of these tests, making the interpretation of experimental data difficult. This study optimized the procedure of the Morris water maze and the Barnes maze to evaluate spatial learning and memory in rats with the lithium-pilocarpine TLE model (LPM rats). It was demonstrated that LPM rats required a mandatory and prolonged habituation stage for both tests. Therefore, the experimental rats performed relatively well on these tests. Nevertheless, LPM rats exhibited a slower learning process compared to the control rats. LPM rats also showed a reduction in spatial memory formation. This was more pronounced in the Barnes maze. Also, LPM rats utilized a sequential strategy for searching in the Barnes maze and were incapable of developing a more efficient spatial search strategy that is common in control animals. The Barnes maze may be a better choice for assessing search strategies, learning deficits, and spatial memory in rats with TLE when choosing between the two tests. This is because of the risk of unexpected seizure occurrence during the Morris water maze tests, and the potential risks for animal welfare.
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Affiliation(s)
- Alexandra V Dyomina
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS (IEPhB), 44, Toreza pr., Saint Petersburg 194223, Russia
| | - Ilya V Smolensky
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS (IEPhB), 44, Toreza pr., Saint Petersburg 194223, Russia; Department of Community Health, University of Fribourg, Chemin du Musée 4, 1700 Fribourg, Switzerland; Department of Biomedicine, University of Basel, Hebelstrasse 20, 4056 Basel, Switzerland
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS (IEPhB), 44, Toreza pr., Saint Petersburg 194223, Russia.
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Clawson W, Waked B, Madec T, Ghestem A, Quilichini PP, Battaglia D, Bernard C. Perturbed Information Processing Complexity in Experimental Epilepsy. J Neurosci 2023; 43:6573-6587. [PMID: 37550052 PMCID: PMC10513075 DOI: 10.1523/jneurosci.0383-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 07/07/2023] [Accepted: 07/20/2023] [Indexed: 08/09/2023] Open
Abstract
Comorbidities, such as cognitive deficits, which often accompany epilepsies, constitute a basal state, while seizures are rare and transient events. This suggests that neural dynamics, in particular those supporting cognitive function, are altered in a permanent manner in epilepsy. Here, we test the hypothesis that primitive processes of information processing at the core of cognitive function (i.e., storage and sharing of information) are altered in the hippocampus and the entorhinal cortex in experimental epilepsy in adult, male Wistar rats. We find that information storage and sharing are organized into substates across the stereotypic states of slow and theta oscillations in both epilepsy and control conditions. However, their internal composition and organization through time are disrupted in epilepsy, partially losing brain state selectivity compared with controls, and shifting toward a regimen of disorder. We propose that the alteration of information processing at this algorithmic level of computation, the theoretical intermediate level between structure and function, may be a mechanism behind the emergent and widespread comorbidities associated with epilepsy, and perhaps other disorders.SIGNIFICANCE STATEMENT Comorbidities, such as cognitive deficits, which often accompany epilepsies, constitute a basal state, while seizures are rare and transient events. This suggests that neural dynamics, in particular those supporting cognitive function, are altered in a permanent manner in epilepsy. Here, we show that basic processes of information processing at the core of cognitive function (i.e., storage and sharing of information) are altered in the hippocampus and the entorhinal cortex (two regions involved in memory processes) in experimental epilepsy. Such disruption of information processing at the algorithmic level itself could underlie the general performance impairments in epilepsy.
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Affiliation(s)
- Wesley Clawson
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
- Allen Discovery Center, Tufts University, Medford, Massachusetts
| | - Benjamin Waked
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Tanguy Madec
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Antoine Ghestem
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Pascale P Quilichini
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Demian Battaglia
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
- University of Strasbourg Institute for Advanced Studies, Strasbourg, France
| | - Christophe Bernard
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
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Di Sapia R, Rizzi M, Moro F, Lisi I, Caccamo A, Ravizza T, Vezzani A, Zanier ER. ECoG spiking activity and signal dimension are early predictive measures of epileptogenesis in a translational mouse model of traumatic brain injury. Neurobiol Dis 2023; 185:106251. [PMID: 37536383 DOI: 10.1016/j.nbd.2023.106251] [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: 04/18/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
The latency between traumatic brain injury (TBI) and the onset of epilepsy (PTE) represents an opportunity for counteracting epileptogenesis. Antiepileptogenesis trials are hampered by the lack of sensitive biomarkers that allow to enrich patient's population at-risk for PTE. We aimed to assess whether specific ECoG signals predict PTE in a clinically relevant mouse model with ∼60% epilepsy incidence. TBI was provoked in adult CD1 male mice by controlled cortical impact on the left parieto-temporal cortex, then mice were implanted with two perilesional cortical screw electrodes and two similar electrodes in the hemisphere contralateral to the lesion site. Acute seizures and spikes/sharp waves were ECoG-recorded during 1 week post-TBI. These early ECoG events were analyzed according to PTE incidence as assessed by measuring spontaneous recurrent seizures (SRS) at 5 months post-TBI. We found that incidence, number and duration of acute seizures during 3 days post-TBI were similar in PTE mice and mice not developing epilepsy (No SRS mice). Control mice with cortical electrodes (naïve, n = 5) or with electrodes and craniotomy (sham, n = 5) exhibited acute seizures but did not develop epilepsy. The daily number of spikes/sharp waves at the perilesional electrodes was increased similarly in PTE (n = 15) and No SRS (n = 8) mice vs controls (p < 0.05, n = 10) from day 2 post-injury. Differently, the daily number of spikes/sharp waves at both contralateral electrodes showed a progressive increase in PTE mice vs No SRS and control mice. In particular, spikes number was higher in PTE vs No SRS mice (p < 0.05) at 6 and 7 days post-TBI, and this measure predicted epilepsy development with high accuracy (AUC = 0.77, p = 0.03; CI 0.5830-0.9670). The cut-off value was validated in an independent cohort of TBI mice (n = 12). The daily spike number at the contralateral electrodes showed a circadian distribution in PTE mice which was not observed in No SRS mice. Analysis of non-linear dynamics at each electrode site showed changes in dimensionality during 4 days post-TBI. This measure yielded the best discrimination between PTE and No SRS mice (p < 0.01) at the cortical electrodes contralateral to injury. Data show that epileptiform activity contralateral to the lesion site has the the highest predictive value for PTE in this model reinforcing the hypothesis that the hemisphere contralateral to the lesion core may drive epileptogenic networks after TBI.
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Affiliation(s)
- Rossella Di Sapia
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Massimo Rizzi
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Federico Moro
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Ilaria Lisi
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Alessia Caccamo
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Teresa Ravizza
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Annamaria Vezzani
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy.
| | - Elisa R Zanier
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy.
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Kowalczyk T, Staszelis A, Bocian R, Siwiec M, Sowa JE, Tokarski K, Kaźmierska-Grębowska P, Caban B. Posterior hypothalamic theta rhythm: Electrophysiological basis and involvement of glutamatergic receptors. Hippocampus 2023; 33:844-861. [PMID: 36688619 DOI: 10.1002/hipo.23500] [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: 06/24/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/24/2023]
Abstract
The posterior hypothalamic area (PHa), including the supramammillary nucleus (SuM) and posterior hypothalamic nuclei, forms a crucial part of the ascending brainstem hippocampal synchronizing pathway, that is involved in the frequency programming and modulation of rhythmic theta activity generated in limbic structures. Recent investigations show that in addition to being a modulator of limbic theta activity, the PHa is capable of producing well-synchronized local theta field potentials by itself. The purpose of this study was to examine the ability of the PHa to generate theta field potentials and accompanying cell discharges in response to glutamatergic stimulation under both in vitro and in vivo conditions. The second objective was to examine the electrophysiological properties of neurons located in the SuM and posterior hypothalamic nuclei. Extracellular in vivo and in vitro as well as intracellular in vitro experiments revealed that glutamatergic stimulation of PHa with kainic acid induces well-synchronized local theta field oscillations in both the supramammillary and posterior hypothalamic nuclei. Furthermore, the glutamatergic PHa theta rhythm recorded extracellularly was accompanied by the activity of specific subtypes of theta-related neurons. We identify, for the first time, a subpopulation of supramammillary and posterior hypothalamic neurons that express clear subthreshold membrane potential oscillations in the theta frequency range.
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Affiliation(s)
- Tomasz Kowalczyk
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Agata Staszelis
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Renata Bocian
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Marcin Siwiec
- Department of Physiology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Joanna E Sowa
- Department of Physiology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Krzysztof Tokarski
- Department of Physiology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | | | - Bartosz Caban
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
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Noguchi A, Yamashiro K, Matsumoto N, Ikegaya Y. Theta oscillations represent collective dynamics of multineuronal membrane potentials of murine hippocampal pyramidal cells. Commun Biol 2023; 6:398. [PMID: 37045975 PMCID: PMC10097823 DOI: 10.1038/s42003-023-04719-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/16/2023] [Indexed: 04/14/2023] Open
Abstract
Theta (θ) oscillations are one of the characteristic local field potentials (LFPs) in the hippocampus that emerge during spatial navigation, exploratory sniffing, and rapid eye movement sleep. LFPs are thought to summarize multineuronal events, including synaptic currents and action potentials. However, no in vivo study to date has directly interrelated θ oscillations with the membrane potentials (Vm) of multiple neurons, and it remains unclear whether LFPs can be predicted from multineuronal Vms. Here, we simultaneously patch-clamp up to three CA1 pyramidal neurons in awake or anesthetized mice and find that the temporal evolution of the power and frequency of θ oscillations in Vms (θVms) are weakly but significantly correlate with LFP θ oscillations (θLFP) such that a deep neural network could predict the θLFP waveforms based on the θVm traces of three neurons. Therefore, individual neurons are loosely interdependent to ensure freedom of activity, but they partially share information to collectively produce θLFP.
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Affiliation(s)
- Asako Noguchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Kotaro Yamashiro
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Nobuyoshi Matsumoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, 113-0033, Japan
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka, 565-0871, Japan
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12
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Milh M. Before the first seizure: The developmental imprint of infant epilepsy on neurodevelopment. Rev Neurol (Paris) 2023; 179:330-336. [PMID: 36907712 DOI: 10.1016/j.neurol.2023.01.725] [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: 12/02/2022] [Revised: 01/26/2023] [Accepted: 01/28/2023] [Indexed: 03/12/2023]
Abstract
In light of the heterogeneity of epilepsy, both from a clinical and from an etiological perspective, it is difficult to establish a link between epilepsy and development that can be generalized to all infantile epilepsies. In general however, early-onset epilepsy has a poor developmental prognosis that is significantly linked to several parameters: age at first seizure, drug resistance, treatment, and etiology. This paper discusses the relationship between visible epilepsy parameters (those that allow the diagnosis of epilepsy) and neurodevelopment in infants, with special focus on Dravet syndrome and KCNQ2-related epilepsy, two common developmental and epileptic encephalopathies; and focal epilepsy caused by focal cortical dysplasia, which often begins during infancy. There are a number of reasons why it is difficult to dissect the relationship between seizures and their causes, and we suggest a conceptual model in which epilepsy is a neurodevelopmental disorder whose severity is determined by how the disease imprints itself on the developmental process rather than by the symptoms or etiology. The precocity of this developmental imprint may explain why treating seizures once they occur can have a very slight beneficial effect on development.
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Affiliation(s)
- M Milh
- Service de neurologie pédiatrique, Timone children hospital, Aix-Marseille université, AP-HM, 264, rue Saint Pierre, 13005 Marseille, France.
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13
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Casillas-Espinosa PM, Anderson A, Harutyunyan A, Li C, Lee J, Braine EL, Brady RD, Sun M, Huang C, Barlow CK, Shah AD, Schittenhelm RB, Mychasiuk R, Jones NC, Shultz SR, O'Brien TJ. Disease-modifying effects of sodium selenate in a model of drug-resistant, temporal lobe epilepsy. eLife 2023; 12:e78877. [PMID: 36892461 PMCID: PMC10208637 DOI: 10.7554/elife.78877] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 03/08/2023] [Indexed: 03/10/2023] Open
Abstract
There are no pharmacological disease-modifying treatments with an enduring effect to mitigate the seizures and comorbidities of established chronic temporal lobe epilepsy (TLE). This study aimed to evaluate for disease modifying effects of sodium selenate treatment in the chronically epileptic rat post-status epilepticus (SE) model of drug-resistant TLE. Wistar rats underwent kainic acid-induced SE or sham. Ten-weeks post-SE, animals received sodium selenate, levetiracetam, or vehicle subcutaneousinfusion continuously for 4 weeks. To evaluate the effects of the treatments, one week of continuous video-EEG was acquired before, during, and 4, 8 weeks post-treatment, followed by behavioral tests. Targeted and untargeted proteomics and metabolomics were performed on post-mortem brain tissue to identify potential pathways associated with modified disease outcomes. Telomere length was investigated as a novel surrogate marker of epilepsy disease severity in our current study. The results showed that sodium selenate treatment was associated with mitigation of measures of disease severity at 8 weeks post-treatment cessation; reducing the number of spontaneous seizures (p< 0.05), cognitive dysfunction (p< 0.05), and sensorimotor deficits (p< 0.01). Moreover, selenate treatment was associated with increased protein phosphatase 2A (PP2A) expression, reduced hyperphosphorylated tau, and reversed telomere length shortening (p< 0.05). Network medicine integration of multi-omics/pre-clinical outcomes identified protein-metabolite modules positively correlated with TLE. Our results provide evidence that treatment with sodium selenate results in a sustained disease-modifying effect in chronically epileptic rats in the post-KA SE model of TLE, including improved comorbid learning and memory deficits.
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Affiliation(s)
- Pablo M Casillas-Espinosa
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
- Monash Proteomics & Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash UniversityClayton, VictoriaAustralia
| | - Alison Anderson
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Anna Harutyunyan
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Crystal Li
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Jiyoon Lee
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
| | - Emma L Braine
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Rhys D Brady
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Mujun Sun
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Cheng Huang
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Christopher K Barlow
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Anup D Shah
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Ralf B Schittenhelm
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Nigel C Jones
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Sandy R Shultz
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Terence J O'Brien
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
- Monash Proteomics & Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash UniversityClayton, VictoriaAustralia
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14
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Yang CCH, Kuo TBJ, Chen CH, Li WY, Hung CT, Li JY. Older rats show slow modulation of hippocampal theta rhythm during voluntary running. Exp Gerontol 2023; 173:112092. [PMID: 36669709 DOI: 10.1016/j.exger.2023.112092] [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: 08/07/2022] [Revised: 12/18/2022] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Aging causes brain function degeneration and slows many motor and behavioural responses. The hippocampal theta rhythm (4-12 Hz) is related to cognition and locomotion. However, the findings on aging-related changes in the frequency and amplitude of hippocampal theta oscillations have been inconsistent. We hypothesized that older rats have slower responses in terms of hippocampal theta rhythm during voluntary wheel running than do young adult rats. By simultaneously recording electroencephalography and physical activity (PA), we evaluated theta oscillations in 8-week-old (young adult) and 60-week-old (middle-aged) rats before and during wheel running, which was conducted only during the rats' 12-h dark period. To test the alterations of hippocampal theta rhythm in voluntary wheel running, we analyzed the signals without (8-s) or with (2-s) chronological order. No significant difference was observed in total frequency (TP, 4-12 Hz), low-frequency (LT, 4-6.5 Hz), or high-frequency (9.5-12 Hz) theta activity between active waking and overall running in either group. The theta oscillations were slower in the middle-aged rats than in the young adult rats during wheel running but increased during running for both age groups. During wheel running, the middle-aged rats exhibited an increased LT, which was related to PA. On the basis of the chronological order of running, the young adult rats exhibited increased TP, and the middle-aged rats exhibited significant increases in middle-frequency (MT, 6.5-9.5 Hz) theta activity. The dominant modulations of MT in the middle-aged rats may have caused nonsignificant changes in total activity. These between-group differences in theta rhythm characteristics during voluntary running provide insights into age-related brain function decline.
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Affiliation(s)
- Cheryl C H Yang
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Terry B J Kuo
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Clinical Research Center, Tsoutun Psychiatric Center, Ministry of Health and Welfare, Nantou, Taiwan
| | - Chun-Hsiu Chen
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Wei-Yi Li
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chang-Tsen Hung
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Jia-Yi Li
- Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan.
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15
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Kilias A, Tulke S, Barheier N, Ruther P, Häussler U. Integration of the CA2 region in the hippocampal network during epileptogenesis. Hippocampus 2023; 33:223-240. [PMID: 36421040 DOI: 10.1002/hipo.23479] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/14/2022] [Accepted: 11/02/2022] [Indexed: 11/26/2022]
Abstract
The CA2 pyramidal cells are mostly resistant to cell death in mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis, but they are aberrantly integrated into the epileptic hippocampal network via mossy fiber sprouting. Furthermore, they show increased excitability in vitro in hippocampal slices obtained from human MTLE specimens or animal epilepsy models. Although these changes promote CA2 to contribute to epileptic activity (EA) in vivo, the role of CA2 in the epileptic network within and beyond the sclerotic hippocampus is still unclear. We used the intrahippocampal kainate mouse model for MTLE, which recapitulates most features of the human disease including pharmacoresistant epileptic seizures and hippocampal sclerosis, with preservation of dentate gyrus (DG) granule cells and CA2 pyramidal cells. In vivo recordings with electrodes in CA2 and the DG showed that EA occurs at high coincidence between the ipsilateral DG and CA2 and current source density analysis of silicon probe recordings in dorsal ipsilateral CA2 revealed CA2 as a local source of EA. Cell-specific viral tracing in Amigo2-icreERT2 mice confirmed the preservation of the axonal projection from ipsilateral CA2 pyramidal cells to contralateral CA2 under epileptic conditions and indeed, EA propagated from ipsi- to contralateral CA2 with increasing likelihood with time after KA injection, but always at lower intensity than within the ipsilateral hippocampus. Furthermore, we show that CA2 presents with local theta oscillations and like the DG, shows a pathological reduction of theta frequency already from 2 days after KA onward. The early changes in activity might be facilitated by the loss of glutamic acid decarboxylase 67 (Gad67) mRNA-expressing interneurons directly after the initial status epilepticus in ipsi- but not contralateral CA2. Together, our data highlight CA2 as an active player in the epileptic network and with its contralateral connections as one possible router of aberrant activity.
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Affiliation(s)
- Antje Kilias
- Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Susanne Tulke
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Nicole Barheier
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Patrick Ruther
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
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16
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Mohammadi E, Nikbakht F, Vazifekhah S, Babae JF, Jogataei MT. Evaluation the cognition-improvement effects of N-acetyl cysteine in experimental temporal lobe epilepsy in rat. Behav Brain Res 2023; 440:114263. [PMID: 36563904 DOI: 10.1016/j.bbr.2022.114263] [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: 09/01/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Memory impairment is a critical issue in patients with temporal lobe epilepsy (TLE). Neuronal loss within the hippocampus and recurrent seizures may cause cognitive impairment in TLE. N -acetyl cysteine (NAC) is a sulfur-containing amino acid cysteine that is currently being investigated due to its protective effects on neurodegenerative disorders. NAC was orally administrated at a dose of 100 mg/kg for 8 days (7-day pretreatment and 1-day post-surgery). Neuronal viability, mTOR protein level, and spatial memory were detected in the kainite temporal epilepsy model via Nissl staining, western blot method, and Morris water maze task, respectively. Results showed that NAC delayed seizure activity and ameliorated memory deficit induced by Kainic acid. Histological analysis showed that NAC significantly increased the number of intact neurons in CA3 and hilar areas of the hippocampus following the induction of epilepsy. NAC also modulated the mTOR protein level 5 days after epilepsy compared to the KA-induced group. CONCLUSION: These results suggest that NAC improved memory impairment via anticonvulsant and neuroprotective activity and, in all probability, by lowering the level of mTOR.
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Affiliation(s)
- Ekram Mohammadi
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, University of Medical Sciences, Tehran Iran
| | - Farnaz Nikbakht
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, University of Medical Sciences, Tehran Iran.
| | - Somayeh Vazifekhah
- Department of Basic Sciences, Sari Branch. Islamic Azad University, Sari, Iran
| | - Javad Fahanik Babae
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohamad Taghi Jogataei
- Cellular and Molecular Research Center and Department of Anatomy, School of Medicine, University of Medical Sciences, Tehran Iran
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17
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Yin L, Zhang J, Ma H, Zhang X, Fan Z, Yang Y, Li M, Han J, Zhang X. Selective activation of cholinergic neurotransmission from the medial septal nucleus to hippocampal pyramidal neurones improves sepsis-induced cognitive deficits in mice. Br J Anaesth 2023; 130:573-584. [PMID: 36813621 DOI: 10.1016/j.bja.2023.01.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 12/15/2022] [Accepted: 01/07/2023] [Indexed: 02/22/2023] Open
Abstract
BACKGROUND Sepsis-associated encephalopathy is characterised by cognitive dysfunction, and might be mediated by deficits in neurotransmission. Reduced cholinergic neurotransmission in the hippocampus impairs memory function. We assessed real-time alterations of acetylcholine neurotransmission from the medial septal nucleus to the hippocampus, and explored whether sepsis-induced cognitive deficits can be relieved by activating upstream cholinergic projections. METHOD Lipopolysaccharide (LPS) injection or caecal ligation and puncture (CLP) was used to induce sepsis and associated neuroinflammation in wild-type and mutant mice. Adeno-associated viruses for calcium and acetylcholine imaging, and for optogenetic and chemogenetic modulation of cholinergic neurones were injected into the hippocampus or medial septum, and a 200-μm-diameter optical fibre was implanted to collect acetylcholine and calcium signals. Cholinergic activity of the medial septum was manipulated and combined with cognitive assessment after LPS injection or CLP. RESULTS Intracerebroventricular LPS injection reduced postsynaptic acetylcholine (from 0.146 [0.001] to 0.0047 [0.0005]; p=0.004) and calcium (from 0.0236 [0.0075] to 0.0054 [0.0026]; p=0.0388) signals in hippocampal Vglut2-positive glutamatergic neurones, whereas optogenetic activation of cholinergic neurones in the medial septum reversed LPS-induced reductions in these two signals. Intraperitoneal LPS injection decreased acetylcholine concentration in the hippocampus (476 [20] pg ml-1 to 382 [14] pg ml-1; p=0.0001). Reduction in long-term potentiation (238 [23] % to 150 [12] %; p=0.0082) and enhancement of hippocampal pyramidal neurone action potential frequency (5.8 [1.5] Hz to 8.2 [1.8] Hz; p=0.0343) were relieved, and neurocognitive performance was improved by chemogenetic activation of cholinergic innervation of the hippocampus 3 days after LPS injection in septic mice. CONCLUSIONS Systemic or local LPS reduced cholinergic neurotransmission from the medial septum to hippocampal pyramidal neurones, and their selective activation alleviated defects in hippocampal neuronal function and synaptic plasticity and ameliorated memory deficits in sepsis model mice through enhanced cholinergic neurotransmission. This provides a basis for targeting cholinergic signalling to the hippocampus in sepsis-induced encephalopathy.
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Affiliation(s)
- Lu Yin
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jinming Zhang
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, China
| | - Hongwei Ma
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xinxin Zhang
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zhongmin Fan
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yongheng Yang
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Mengyun Li
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jing Han
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, China.
| | - Xijing Zhang
- Department of Critical Care Medicine and Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
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Soula M, Maslarova A, Harvey RE, Valero M, Brandner S, Hamer H, Fernández-Ruiz A, Buzsáki G. Interictal epileptiform discharges affect memory in an Alzheimer's Disease mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528683. [PMID: 36824810 PMCID: PMC9949089 DOI: 10.1101/2023.02.15.528683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Interictal epileptiform discharges (IEDs) are transient abnormal electrophysiological events commonly observed in epilepsy patients but are also present in other neurological disease, such as Alzheimer's Disease (AD). Understanding the role IEDs have on the hippocampal circuit is important for our understanding of the cognitive deficits seen in epilepsy and AD. We characterize and compare the IEDs of human epilepsy patients from microwire hippocampal recording with those of AD transgenic mice with implanted multi-layer hippocampal silicon probes. Both the local field potential features and firing patterns of pyramidal cells and interneurons were similar in mouse and human. We found that as IEDs emerged from the CA3-1 circuits, they recruited pyramidal cells and silenced interneurons, followed by post-IED suppression. IEDs suppressed the incidence and altered the properties of physiological sharp-wave ripples (SPW-Rs), altered their physiological properties, and interfered with the replay of place field sequences in a maze. In addition, IEDs in AD mice inversely correlated with daily memory performance. Together, our work implicates that IEDs may present a common and epilepsy-independent phenomenon in neurodegenerative diseases that perturbs hippocampal-cortical communication and interferes with memory. Significant Statement Prevalence of neurodegenerative diseases and the number of people with dementia is increasing steadily. Therefore, novel treatment strategies for learning and memory disorders are urgently necessary. IEDs, apart from being a surrogate for epileptic brain regions, have also been linked to cognitive decline. Here we report that IEDs in human epilepsy patients and AD mouse models have similar local field potential characteristics and associated firing patterns of pyramidal cells and interneurons. Mice with more IEDs displayed fewer hippocampal SPW-Rs, poorer replay of spatial trajectories, and decreased memory performance. IED suppression is an unexplored target to treat cognitive dysfunction in neurodegenerative diseases.
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19
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Chauvière L. Early cognitive comorbidities before disease onset: A common symptom towards prevention of related brain diseases? Heliyon 2022; 8:e12259. [PMID: 36590531 PMCID: PMC9800323 DOI: 10.1016/j.heliyon.2022.e12259] [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: 08/08/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/15/2022] Open
Abstract
Brain diseases are very heterogeneous; however they also display multiple common risk factors and comorbidities. With a paucity of disease-modifying therapies, prevention became a health priority. Towards prevention, one strategy is to focus on similar symptoms of brain diseases occurring before disease onset. Cognitive deficits are a promising candidate as they occur across brain diseases before disease onset. Based on recent research, this review highlights the similarity of brain diseases and discusses how early cognitive deficits can be exploited to tackle disease prevention. After briefly introducing common risk factors, I review common comorbidities across brain diseases, with a focus on cognitive deficits before disease onset, reporting both experimental and clinical findings. Next, I describe network abnormalities associated with early cognitive deficits and discuss how these abnormalities can be targeted to prevent disease onset. A scenario on brain disease etiology with the idea that early cognitive deficits may constitute a common symptom of brain diseases is proposed.
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20
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Wang Z, Mengoni P. Seizure classification with selected frequency bands and EEG montages: a Natural Language Processing approach. Brain Inform 2022; 9:11. [PMID: 35622175 PMCID: PMC9142724 DOI: 10.1186/s40708-022-00159-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/17/2022] [Indexed: 11/10/2022] Open
Abstract
Individualized treatment is crucial for epileptic patients with different types of seizures. The differences among patients impact the drug choice as well as the surgery procedure. With the advance in machine learning, automatic seizure detection can ease the manual time-consuming and labor-intensive procedure for diagnose seizure in the clinical setting. In this paper, we present an electroencephalography (EEG) frequency bands (sub-bands) and montages selection (sub-zones) method for classifier training that exploits Natural Language Processing from individual patients' clinical report. The proposed approach is targeting for individualized treatment. We integrated the prior knowledge from patient's reports into the classifier-building process, mimicking the authentic thinking process of experienced neurologist's when diagnosing seizure using EEG. The keywords from clinical documents are mapped to the EEG data in terms of frequency bands and scalp EEG electrodes. The data of experiments are from the Temple University Hospital EEG seizure corpus, and the dataset is divided based on each group of patients with same seizure type and same recording electrode references. The classifier includes Random Forest, Support Vector Machine and Multi-Layer Perceptron. The classification performance indicates that competitive results can be achieve with a small portion of EEG the data. Using the sub-zones selection for Generalized Seizures (GNSZ) on all three electrodes, data are reduced by nearly 50% while the performance metrics remain at the same level with the whole frequency and zones. Moreover, when selecting by sub-zones and sub-bands together for GNSZ with Linked Ears reference, the data range reduced to 0.3% of whole range, and the performance deviates less than 3% from the results with whole range of data. Results show that using proposed approach may lead to more efficient implementations of the seizure classifier to be executed on power-efficient devices for long lasting real-time seizures detection.
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Affiliation(s)
- Ziwei Wang
- Institute of Interdisciplinary Studies, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR China
| | - Paolo Mengoni
- Department of Journalism, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR China
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21
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Khalife MR, Scott RC, Hernan AE. Mechanisms for Cognitive Impairment in Epilepsy: Moving Beyond Seizures. Front Neurol 2022; 13:878991. [PMID: 35645970 PMCID: PMC9135108 DOI: 10.3389/fneur.2022.878991] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
There has been a major emphasis on defining the role of seizures in the causation of cognitive impairments like memory deficits in epilepsy. Here we focus on an alternative hypothesis behind these deficits, emphasizing the mechanisms of information processing underlying healthy cognition characterized as rate, temporal and population coding. We discuss the role of the underlying etiology of epilepsy in altering neural networks thereby leading to both the propensity for seizures and the associated cognitive impairments. In addition, we address potential treatments that can recover the network function in the context of a diseased brain, thereby improving both seizure and cognitive outcomes simultaneously. This review shows the importance of moving beyond seizures and approaching the deficits from a system-level perspective with the guidance of network neuroscience.
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Affiliation(s)
- Mohamed R. Khalife
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
| | - Rod C. Scott
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
- Institute of Child Health, Neurosciences Unit University College London, London, United Kingdom
| | - Amanda E. Hernan
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
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22
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Nair KP, Salaka RJ, Srikumar BN, Kutty BM, Rao BSS. Enriched environment rescues impaired sleep-wake architecture and abnormal neural dynamics in chronic epileptic rats. Neuroscience 2022; 495:97-114. [DOI: 10.1016/j.neuroscience.2022.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 11/16/2022]
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Fu X, Wang Y, Belkacem AN, Cao Y, Cheng H, Zhao X, Chen S, Chen C. Interictal Spike and Loss of Hippocampal Theta Rhythm Recorded by Deep Brain Electrodes during Epileptogenesis. SENSORS 2022; 22:s22031114. [PMID: 35161860 PMCID: PMC8838088 DOI: 10.3390/s22031114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 02/01/2023]
Abstract
Epileptogenesis is the gradual dynamic process that progressively led to epilepsy, going through the latent stage to the chronic stage. During epileptogenesis, how the abnormal discharges make theta rhythm loss in the deep brain remains not clear. In this paper, a loss of theta rhythm was estimated based on time–frequency power using the longitudinal electroencephalography (EEG), recorded by deep brain electrodes (e.g., the intracortical microelectrodes such as stereo-EEG electrodes) with monitored epileptic spikes in a rat from the first region in the hippocampal circuit. Deep-brain EEG was collected from the period between adjacent sporadic interictal spikes (lasting 3.56 s—35.38 s) to the recovery period without spikes by videos while the rats were performing exploration. We found that loss of theta rhythm became more serious during the period between adjacent interictal spikes than during the recovery period without spike, and during epileptogenesis, more loss was observed at the acute stage than the chronic stage. We concluded that the emergence of the interictal spike was the direct cause of loss of theta rhythm, and the inhibitory effect of the interictal spike on ongoing theta rhythm was persistent as well as time dependent during epileptogenesis. With the help of the intracortical microelectrodes, this study provides a temporary proof of interictal spikes to produce ongoing theta rhythm loss, suggesting that the interictal spikes could correlate with the epileptogenesis process, display a time-dependent feature, and might be a potential biomarker to evaluate the deficits in theta-related memory in the brain.
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Affiliation(s)
- Xiaoxuan Fu
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (X.F.); (Y.W.); (Y.C.); (H.C.); (X.Z.)
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29464, USA
| | - Youhua Wang
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (X.F.); (Y.W.); (Y.C.); (H.C.); (X.Z.)
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Abdelkader Nasreddine Belkacem
- Department of Computer and Network Engineering, College of Information Technology, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates;
| | - Yingxin Cao
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (X.F.); (Y.W.); (Y.C.); (H.C.); (X.Z.)
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Hao Cheng
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (X.F.); (Y.W.); (Y.C.); (H.C.); (X.Z.)
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Xiaohu Zhao
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (X.F.); (Y.W.); (Y.C.); (H.C.); (X.Z.)
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Shenghua Chen
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (X.F.); (Y.W.); (Y.C.); (H.C.); (X.Z.)
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China
- Correspondence: (S.C.); (C.C.)
| | - Chao Chen
- Key Laboratory of Complex System Control Theory and Application, Tianjin University of Technology, Tianjin 300384, China
- Correspondence: (S.C.); (C.C.)
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24
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Sayahi Z, Komaki A, Saidi Jam M, Karimi SA, Raoufi S, Mardani P, Naderishahab M, Sarihi A, Mirnajafi-Zadeh J. Effect of ramosetron, a 5-HT 3 receptor antagonist on the severity of seizures and memory impairment in electrical amygdala kindled rats. J Physiol Sci 2022; 72:1. [PMID: 35034601 PMCID: PMC10717980 DOI: 10.1186/s12576-022-00825-5] [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: 03/16/2021] [Accepted: 01/04/2022] [Indexed: 11/10/2022]
Abstract
The entorhinal cortex (EC) plays a pivotal role in epileptogenesis and seizures. EC expresses high density of serotonergic receptors, especially 5-HT3 receptors. Cognitive impairment is common among people with epilepsy. The present study investigated the role of 5-HT3 receptor on the severity of seizures and learning and memory impairment by electrical kindling of amygdala in rats. The amygdala kindling was conducted in a chronic kindling manner in male Wistar rats. In fully kindled animals, ramosetron (as a potent and selective 5-HT3 receptor antagonist) was microinjected unilaterally (ad doses of 1, 10 or 100 µg/0.5 µl) into the EC 5 min before the novel object recognition (NOR) and Y-maze tests or kindling stimulations. Applying ramosetron at the concentration of 100 μg/0.5 µl (but not at 1 and 10 µg/0.5 µl) reduced afterdischarge (AD) duration and increased stage 4 latency in the kindled rats. Moreover, the obtained data from the NOR test showed that treatment by ramosetron (10 and 100 µg/0.5 µl) increased the discrimination index in the fully kindled animals. Microinjection of ramosetron (10 and 100 µg/0.5 µl) in fully kindled animals reversed the kindling induced changes in the percentage of spontaneous alternation in Y-maze task. The findings demonstrated an anticonvulsant role for a selective 5-HT3 receptor antagonist microinjected into the EC, therefore, suggesting an excitatory role for the EC 5-HT3 receptors in the amygdala kindling model of epilepsy. This anticonvulsive effect was accompanied with a restoring effect on cognitive behavior in NOR and Y-maze tests.
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Affiliation(s)
- Zeynab Sayahi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Shahid Fahmideh Street, 6517838736, Hamadan, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Shahid Fahmideh Street, 6517838736, Hamadan, Iran
- Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Masoud Saidi Jam
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Seyed Asaad Karimi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Shahid Fahmideh Street, 6517838736, Hamadan, Iran
- Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Safoura Raoufi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Shahid Fahmideh Street, 6517838736, Hamadan, Iran
| | - Parastoo Mardani
- Department of Biology, Faculty of Sciences, Payame Noor University, Sanandaj, Iran
| | - Marzieh Naderishahab
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Shahid Fahmideh Street, 6517838736, Hamadan, Iran
| | - Abdolrahman Sarihi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Shahid Fahmideh Street, 6517838736, Hamadan, Iran.
- Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, 1411713116, Tehran, Iran.
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25
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Righes Marafiga J, Vendramin Pasquetti M, Calcagnotto ME. In vitro Oscillation Patterns Throughout the Hippocampal Formation in a Rodent Model of Epilepsy. Neuroscience 2021; 479:1-21. [PMID: 34710537 DOI: 10.1016/j.neuroscience.2021.10.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022]
Abstract
Specific oscillatory patterns are considered biomarkers of pathological neuronal network in brain diseases, such as epilepsy. However, the dynamics of underlying oscillations during the epileptogenesis throughout the hippocampal formation in the temporal lobe epilepsy is not clear. Here, we characterized in vitro oscillatory patterns within the hippocampal formation of epileptic rats, under 4-aminopyridine (4-AP)-induced hyperexcitability and during the spontaneous network activity, at two periods of epileptogenesis. First, at the beginning of epileptic chronic phase, 30 days post-pilocarpine-induced Status Epilepticus (SE). Second, at the established epilepsy, 60 days post-SE. The 4-AP-bathed slices from epileptic rats had increased susceptibility to ictogenesis in CA1 at 30 days post-SE, and in entorhinal cortex and dentate gyrus at 60 days post-SE. Higher power and phase coherence were detected mainly for gamma and/or high frequency oscillations (HFOs), in a region- and stage-specific manner. Interestingly, under spontaneous network activity, even without 4-AP-induced hyperexcitability, slices from epileptic animals already exhibited higher power of gamma and HFOs in different areas of hippocampal formation at both periods of epileptogenesis, and higher phase coherence in fast ripples at 60 days post-SE. These findings reinforce the critical role of gamma and HFOs in each one of the hippocampal formation areas during ongoing neuropathological processes, tuning the neuronal network to epilepsy.
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Affiliation(s)
- Joseane Righes Marafiga
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory (NNNESP Lab.), 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 (NNNESP Lab.), 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 (NNNESP Lab.), 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.
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26
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Deficits in Behavioral and Neuronal Pattern Separation in Temporal Lobe Epilepsy. J Neurosci 2021; 41:9669-9686. [PMID: 34620720 PMCID: PMC8612476 DOI: 10.1523/jneurosci.2439-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 09/09/2021] [Accepted: 09/21/2021] [Indexed: 11/21/2022] Open
Abstract
In temporal lobe epilepsy, the ability of the dentate gyrus to limit excitatory cortical input to the hippocampus breaks down, leading to seizures. The dentate gyrus is also thought to help discriminate between similar memories by performing pattern separation, but whether epilepsy leads to a breakdown in this neural computation, and thus to mnemonic discrimination impairments, remains unknown. Here we show that temporal lobe epilepsy is characterized by behavioral deficits in mnemonic discrimination tasks, in both humans (females and males) and mice (C57Bl6 males, systemic low-dose kainate model). Using a recently developed assay in brain slices of the same epileptic mice, we reveal a decreased ability of the dentate gyrus to perform certain forms of pattern separation. This is because of a subset of granule cells with abnormal bursting that can develop independently of early EEG abnormalities. Overall, our results linking physiology, computation, and cognition in the same mice advance our understanding of episodic memory mechanisms and their dysfunction in epilepsy.SIGNIFICANCE STATEMENT People with temporal lobe epilepsy (TLE) often have learning and memory impairments, sometimes occurring earlier than the first seizure, but those symptoms and their biological underpinnings are poorly understood. We focused on the dentate gyrus, a brain region that is critical to avoid confusion between similar memories and is anatomically disorganized in TLE. We show that both humans and mice with TLE experience confusion between similar situations. This impairment coincides with a failure of the dentate gyrus to disambiguate similar input signals because of pathologic bursting in a subset of neurons. Our work bridges seizure-oriented and memory-oriented views of the dentate gyrus function, suggests a mechanism for cognitive symptoms in TLE, and supports a long-standing hypothesis of episodic memory theories.
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27
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Arski ON, Wong SM, Warsi NM, Martire DJ, Ochi A, Otsubo H, Donner E, Jain P, Kerr EN, Smith ML, Ibrahim GM. Spectral changes following resective epilepsy surgery and neurocognitive function in children with epilepsy. J Neurophysiol 2021; 126:1614-1621. [PMID: 34550020 DOI: 10.1152/jn.00434.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Decelerated resting cortical oscillations, high-frequency activity, and enhanced cross-frequency interactions are features of focal epilepsy. The association between electrophysiological signal properties and neurocognitive function, particularly following resective surgery, is, however, unclear. In the current report, we studied intraoperative recordings from intracranial electrodes implanted in seven children with focal epilepsy and analyzed the spectral dynamics both before and after surgical resection of the hypothesized seizure focus. The associations between electrophysiological spectral signatures and each child's neurocognitive profiles were characterized using a partial least squares analysis. We find that extent of spectral alteration at the periphery of surgical resection, as indexed by slowed resting frequency and its acceleration following surgery, is associated with baseline cognitive deficits in children. The current report provides evidence supporting the relationship between altered spectral properties in focal epilepsy and neuropsychological deficits in children. In particular, these findings suggest a critical role of disrupted thalamocortical rhythms, which are believed to underlie the spectral alterations we describe, in both epileptogenicity and neurocognitive function.NEW & NOTEWORTHY Spectral alterations marked by decelerated resting oscillations and ectopic high-frequency activity have been noted in focal epilepsy. We leveraged intraoperative recordings from chronically implanted electrodes pre- and postresection to understand the association between these electrophysiological phenomena and neuropsychological function. We find that the extent of spectral alteration, indexed by slowed resting frequency and its acceleration following resection, is associated with baseline cognitive deficits. These findings provide novel insights into neurocognitive impairments in focal epilepsy.
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Affiliation(s)
- Olivia N Arski
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Simeon M Wong
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Nebras M Warsi
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.,Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Daniel J Martire
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Ayako Ochi
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Hiroshi Otsubo
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth Donner
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Puneet Jain
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Division of Psychology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Mary Lou Smith
- Division of Psychology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - George M Ibrahim
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.,Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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28
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Cruz Del Angel Y, Orfila JE, Herson PS, Brooks-Kayal A, González MI. Down-regulation of AMPA receptors and long-term potentiation during early epileptogenesis. Epilepsy Behav 2021; 124:108320. [PMID: 34592633 DOI: 10.1016/j.yebeh.2021.108320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
Epilepsy is a brain disorder characterized by the occurrence of recurrent spontaneous seizures. Behavioral disorders and altered cognition are frequent comorbidities affecting the quality of life of people with epilepsy. These impairments are undoubtedly multifactorial and the specific mechanisms underlying these comorbidities are largely unknown. Long-lasting alterations in synaptic strength due to changes in expression, phosphorylation, or function of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) have been associated with alterations in neuronal synaptic plasticity. In particular, alterations in hippocampal long-term potentiation (LTP), a well-accepted model of learning and memory, have been associated with altered cognition in epilepsy. Here, we analyzed the effects of pilocarpine-induced status epilepticus (SE) on AMPARs to determine if alterations in AMPAR signaling might be one of the mechanisms contributing to altered cognition during epilepsy. We found alterations in the phosphorylation and plasma membrane expression of AMPARs. In addition, we detected altered expression of GRIP, a key scaffolding protein involved in the proper distribution of AMPARs at the neuronal cell surface. Interestingly, a functional analysis revealed that these molecular changes are linked to impaired LTP. Together, these observations suggest that seizure-induced alterations in the molecular machinery regulating AMPARs likely impact the neuron's ability to support synaptic plasticity that is required for learning and memory.
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Affiliation(s)
- Yasmin Cruz Del Angel
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - James E Orfila
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paco S Herson
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Amy Brooks-Kayal
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Marco I González
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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29
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Izadi A, Schedlbauer A, Ondek K, Disse G, Ekstrom AD, Cowen SL, Shahlaie K, Gurkoff GG. Early Intervention via Stimulation of the Medial Septal Nucleus Improves Cognition and Alters Markers of Epileptogenesis in Pilocarpine-Induced Epilepsy. Front Neurol 2021; 12:708957. [PMID: 34557145 PMCID: PMC8452867 DOI: 10.3389/fneur.2021.708957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
Over one-third of patients with temporal lobe epilepsy are refractory to medication. In addition, anti-epileptic drugs often exacerbate cognitive comorbidities. Neuromodulation is an FDA treatment for refractory epilepsy, but patients often wait >20 years for a surgical referral for resection or neuromodulation. Using a rodent model, we test the hypothesis that 2 weeks of theta stimulation of the medial septum acutely following exposure to pilocarpine will alter the course of epileptogenesis resulting in persistent behavioral improvements. Electrodes were implanted in the medial septum, dorsal and ventral hippocampus, and the pre-frontal cortex of pilocarpine-treated rats. Rats received 30 min/day of 7.7 Hz or theta burst frequency on days 4-16 post-pilocarpine, prior to the development of spontaneous seizures. Seizure threshold, spikes, and oscillatory activity, as well as spatial and object-based learning, were assessed in the weeks following stimulation. Non-stimulated pilocarpine animals exhibited significantly decreased seizure threshold, increased spikes, and cognitive impairments as compared to vehicle controls. Furthermore, decreased ventral hippocampal power (6-10 Hz) correlated with both the development of spikes and impaired cognition. Measures of spikes, seizure threshold, and cognitive performance in both acute 7.7 Hz and theta burst stimulated animals were statistically similar to vehicle controls when tested during the chronic phase of epilepsy, weeks after stimulation was terminated. These data indicate that modulation of the septohippocampal circuit early after pilocarpine treatment alters the progression of epileptic activity, resulting in elevated seizure thresholds, fewer spikes, and improved cognitive outcome. Results from this study support that septal theta stimulation has the potential to serve in combination or as an alternative to high frequency thalamic stimulation in refractory cases and that further research into early intervention is critical.
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Affiliation(s)
- Ali Izadi
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, United States.,Center for Neuroscience, University of California, Davis, Davis, CA, United States
| | - Amber Schedlbauer
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, United States
| | - Katelynn Ondek
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, United States.,Center for Neuroscience, University of California, Davis, Davis, CA, United States
| | - Gregory Disse
- Center for Neuroscience, University of California, Davis, Davis, CA, United States
| | - Arne D Ekstrom
- Department of Psychology, University of Arizona, Tucson, AZ, United States.,McKnight Brain Institute, University of Arizona, Tucson, AZ, United States
| | - Stephen L Cowen
- Department of Psychology, University of Arizona, Tucson, AZ, United States.,McKnight Brain Institute, University of Arizona, Tucson, AZ, United States
| | - Kiarash Shahlaie
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, United States.,Center for Neuroscience, University of California, Davis, Davis, CA, United States
| | - Gene G Gurkoff
- Department of Neurological Surgery, University of California, Davis, Sacramento, CA, United States.,Center for Neuroscience, University of California, Davis, Davis, CA, United States
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30
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Faiman I, Smith S, Hodsoll J, Young AH, Shotbolt P. Resting-state EEG for the diagnosis of idiopathic epilepsy and psychogenic nonepileptic seizures: A systematic review. Epilepsy Behav 2021; 121:108047. [PMID: 34091130 DOI: 10.1016/j.yebeh.2021.108047] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 04/28/2021] [Indexed: 12/17/2022]
Abstract
Quantitative markers extracted from resting-state electroencephalogram (EEG) reveal subtle neurophysiological dynamics which may provide useful information to support the diagnosis of seizure disorders. We performed a systematic review to summarize evidence on markers extracted from interictal, visually normal resting-state EEG in adults with idiopathic epilepsy or psychogenic nonepileptic seizures (PNES). Studies were selected from 5 databases and evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2. 26 studies were identified, 19 focusing on people with epilepsy, 6 on people with PNES, and one comparing epilepsy and PNES directly. Results suggest that oscillations along the theta frequency (4-8 Hz) may have a relevant role in idiopathic epilepsy, whereas in PNES there was no evident trend. However, studies were subject to a number of methodological limitations potentially introducing bias. There was often a lack of appropriate reporting and high heterogeneity. Results were not appropriate for quantitative synthesis. We identify and discuss the challenges that must be addressed for valid resting-state EEG markers of epilepsy and PNES to be developed.
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Affiliation(s)
- Irene Faiman
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Camberwell, London SE5 8AB, United Kingdom.
| | - Stuart Smith
- Department of Neurophysiology, Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, United Kingdom.
| | - John Hodsoll
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Camberwell, London SE5 8AB, United Kingdom.
| | - Allan H Young
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Camberwell, London SE5 8AB, United Kingdom; South London and Maudsley NHS Foundation Trust, Bethlem Royal Hospital, Monks Orchard Road, Beckenham, Kent BR3 3BX, United Kingdom.
| | - Paul Shotbolt
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Camberwell, London SE5 8AB, United Kingdom.
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31
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The Role of the Posterior Hypothalamus in the Modulation and Production of Rhythmic Theta Oscillations. Neuroscience 2021; 470:100-115. [PMID: 34271089 DOI: 10.1016/j.neuroscience.2021.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/18/2021] [Accepted: 07/05/2021] [Indexed: 11/24/2022]
Abstract
Theta rhythm recorded as an extracellular synchronous field potential is generated in a number of brain sites including the hippocampus. The physiological occurrence of hippocampal theta rhythm is associated with the activation of a number of structures forming the ascending brainstem-hippocampal synchronizing pathway. Experimental evidence indicates that the supramammillary nucleus and posterior hypothalamic nuclei, considered as the posterior hypothalamic area, comprise a critical node of this ascending pathway. The posterior hypothalamic area plays an important role in movement control, place-learning, memory processing, emotion and arousal. In the light of multiplicity of functions of the posterior hypothalamic area and the influence of theta field oscillations on a number of neural processes, it is the authors' intent to summarize the data concerning the involvement of the supramammillary nucleus and posterior hypothalamic nuclei in the modulation of limbic theta rhythmicity as well as the ability of these brain structures to independently generate theta rhythmicity.
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32
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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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33
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Vera J, Lippmann K. Post-stroke epileptogenesis is associated with altered intrinsic properties of hippocampal pyramidal neurons leading to increased theta resonance. Neurobiol Dis 2021; 156:105425. [PMID: 34119635 DOI: 10.1016/j.nbd.2021.105425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 01/23/2023] Open
Abstract
Brain insults like stroke, trauma or infections often lead to blood-brain barrier-dysfunction (BBBd) frequently resulting into epileptogenesis. Affected patients suffer from seizures and cognitive comorbidities that are potentially linked to altered network oscillations. It has been shown that a hippocampal BBBd in rats leads to in vivo seizures and increased power at theta (3-8 Hz), an important type of network oscillations. However, the underlying cellular mechanisms remain poorly understood. At membrane potentials close to the threshold for action potentials (APs) a subpopulation of CA1 pyramidal cells (PCs) displays intrinsic resonant properties due to an interplay of the muscarine-sensitive K+-current (IM) and the persistent Na+-current (INaP). Such resonant neurons are more excitable and generate more APs when stimulated at theta frequencies, being strong candidates for contributing to hippocampal theta oscillations during epileptogenesis. We tested this hypothesis by characterizing changes in intrinsic properties of hippocampal PCs one week after post-stroke epileptogenesis, a model associated with BBBd, using slice electrophysiology and computer modeling. We find a higher proportion of resonant neurons in BBBd compared to sham animals (47 vs. 29%), accompanied by an increase in their excitability. In contrast, BBBd non-resonant neurons showed a reduced excitability, presented with lower impedance and more positive AP threshold. We identify an increase in IM combined with either a reduction in INaP or an increase in ILeak as possible mechanisms underlying the observed changes. Our results support the hypothesis that a higher proportion of more excitable resonant neurons in the hippocampus contributes to increased theta oscillations and an increased likelihood of seizures in a model of post-stroke epileptogenesis.
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Affiliation(s)
- Jorge Vera
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kristina Lippmann
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, D-04103 Leipzig, Germany.
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Proietti Onori M, Koene LMC, Schäfer CB, Nellist M, de Brito van Velze M, Gao Z, Elgersma Y, van Woerden GM. RHEB/mTOR hyperactivity causes cortical malformations and epileptic seizures through increased axonal connectivity. PLoS Biol 2021; 19:e3001279. [PMID: 34038402 PMCID: PMC8186814 DOI: 10.1371/journal.pbio.3001279] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 06/08/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
Hyperactivation of the mammalian target of rapamycin (mTOR) pathway can cause malformation of cortical development (MCD) with associated epilepsy and intellectual disability (ID) through a yet unknown mechanism. Here, we made use of the recently identified dominant-active mutation in Ras Homolog Enriched in Brain 1 (RHEB), RHEBp.P37L, to gain insight in the mechanism underlying the epilepsy caused by hyperactivation of the mTOR pathway. Focal expression of RHEBp.P37L in mouse somatosensory cortex (SScx) results in an MCD-like phenotype, with increased mTOR signaling, ectopic localization of neurons, and reliable generalized seizures. We show that in this model, the mTOR-dependent seizures are caused by enhanced axonal connectivity, causing hyperexcitability of distally connected neurons. Indeed, blocking axonal vesicle release from the RHEBp.P37L neurons alone completely stopped the seizures and normalized the hyperexcitability of the distally connected neurons. These results provide new evidence of the extent of anatomical and physiological abnormalities caused by mTOR hyperactivity, beyond local malformations, which can lead to generalized epilepsy. Hyperactivation of the mTOR pathway can cause cortical malformations and epilepsy. This study reveals that these effects can be uncoupled and that mTOR hyperactivity in a limited set of neurons induces hyperexcitability in non-targeted, healthy neurons, suggesting that it is actually these changes that may underlie mTOR-driven epileptogenesis.
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Affiliation(s)
- Martina Proietti Onori
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Linda M. C. Koene
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Carmen B. Schäfer
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
| | | | - Zhenyu Gao
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ype Elgersma
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
- * E-mail: (YE); (GMvW)
| | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
- * E-mail: (YE); (GMvW)
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A Simulation on Relation between Power Distribution of Low-Frequency Field Potentials and Conducting Direction of Rhythm Generator Flowing through 3D Asymmetrical Brain Tissue. Symmetry (Basel) 2021. [DOI: 10.3390/sym13050900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although the power of low-frequency oscillatory field potentials (FP) has been extensively applied previously, few studies have investigated the influence of conducting direction of deep-brain rhythm generator on the power distribution of low-frequency oscillatory FPs on the head surface. To address this issue, a simulation was designed based on the principle of electroencephalogram (EEG) generation of equivalent dipole current in deep brain, where a single oscillatory dipole current represented the rhythm generator, the dipole moment for the rhythm generator’s conducting direction (which was orthogonal and rotating every 30 degrees and at pointing to or parallel to the frontal lobe surface) and the (an)isotropic conduction medium for the 3D (a)symmetrical brain tissue. Both the power above average (significant power value, SP value) and its space (SP area) of low-frequency oscillatory FPs were employed to respectively evaluate the strength and the space of the influence. The computation was conducted using the finite element method (FEM) and Hilbert transform. The finding was that either the SP value or the SP area could be reduced or extended, depending on the conducting direction of deep-brain rhythm generator flowing in the (an)isotropic medium, suggesting that the 3D (a)symmetrical brain tissue could decay or strengthen the spatial spread of a rhythm generator conducting in a different direction.
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Kang YJ, Clement EM, Park IH, Greenfield LJ, Smith BN, Lee SH. Vulnerability of cholecystokinin-expressing GABAergic interneurons in the unilateral intrahippocampal kainate mouse model of temporal lobe epilepsy. Exp Neurol 2021; 342:113724. [PMID: 33915166 DOI: 10.1016/j.expneurol.2021.113724] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/26/2021] [Accepted: 04/22/2021] [Indexed: 10/21/2022]
Abstract
Temporal lobe epilepsy (TLE) is characterized by recurrent spontaneous seizures and behavioral comorbidities. Reduced hippocampal theta oscillations and hyperexcitability that contribute to cognitive deficits and spontaneous seizures are present beyond the sclerotic hippocampus in TLE. However, the mechanisms underlying compromised network oscillations and hyperexcitability observed in circuits remote from the sclerotic hippocampus are largely unknown. Cholecystokinin (CCK)-expressing basket cells (CCKBCs) critically participate in hippocampal theta rhythmogenesis, and regulate neuronal excitability. Thus, we examined whether CCKBCs were vulnerable in nonsclerotic regions of the ventral hippocampus remote from dorsal sclerotic hippocampus using the intrahippocampal kainate (IHK) mouse model of TLE, targeting unilateral dorsal hippocampus. We found a decrease in the number of CCK+ interneurons in ipsilateral ventral CA1 regions from epileptic mice compared to those from sham controls. We also found that the number of boutons from CCK+ interneurons was reduced in the stratum pyramidale, but not in other CA1 layers, of ipsilateral hippocampus in epileptic mice, suggesting that CCKBCs are vulnerable. Electrical recordings showed that synaptic connectivity and strength from surviving CCKBCs to CA1 pyramidal cells (PCs) were similar between epileptic mice and sham controls. In agreement with reduced CCKBC number in TLE, electrical recordings revealed a significant reduction in amplitude and frequency of IPSCs in CA1 PCs evoked by carbachol (commonly used to excite CCK+ interneurons) in ventral CA1 regions from epileptic mice versus sham controls. These findings suggest that loss of CCKBCs beyond the hippocampal lesion may contribute to hyperexcitability and compromised network oscillations in TLE.
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Affiliation(s)
- Young-Jin Kang
- Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA; Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Ethan M Clement
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - In-Hyun Park
- Department of Genetics, Yale Stem Cell Center, Yale Child Study Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - Lazar John Greenfield
- Department of Neurology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Bret N Smith
- Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA
| | - Sang-Hun Lee
- Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA; Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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Lenck-Santini PP. Bad Timing for Epileptic Networks: Role of Temporal Dynamics in Seizures and Cognitive Deficits. Epilepsy Curr 2021; 21:15357597211001877. [PMID: 33724060 PMCID: PMC8609592 DOI: 10.1177/15357597211001877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The precise coordination of neuronal activity is critical for optimal brain function. When such coordination fails, this can lead to dire consequences. In this review, I will present evidence that in epilepsy, failed coordination leads not only to seizures but also to alterations of the rhythmical patterns observed in the electroencephalogram and cognitive deficits. Restoring the dynamic coordination of epileptic networks could therefore both improve seizures and cognitive outcomes.
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Wang Y, Shen Y, Cai X, Yu J, Chen C, Tan B, Tan N, Cheng H, Fan X, Wu X, Liu J, Wang S, Wang Y, Chen Z. Deep brain stimulation in the medial septum attenuates temporal lobe epilepsy via entrainment of hippocampal theta rhythm. CNS Neurosci Ther 2021; 27:577-586. [PMID: 33502829 PMCID: PMC8025637 DOI: 10.1111/cns.13617] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
Aims Temporal lobe epilepsy (TLE), often associated with cognitive impairment, is one of the most common types of medically refractory epilepsy. Deep brain stimulation (DBS) shows considerable promise for the treatment of TLE. However, the optimal stimulation targets and parameters of DBS to control seizures and related cognitive impairment are still not fully illustrated. Methods In the present study, we evaluated the therapeutic potential of DBS in the medial septum (MS) on seizures and cognitive function in mouse acute and chronic epilepsy models. Results We found that DBS in the MS alleviated the severity of seizure activities in both kainic acid‐induced acute seizure model and hippocampal‐kindled epilepsy model. DBS showed antiseizure effects with a wide window of effective stimulation frequencies. The antiseizure effects of DBS were mediated by the hippocampal theta rhythm, as atropine, which reversed the DBS‐induced augmentation of the hippocampal theta oscillation, abolished the antiseizure effects of DBS. Further, in the kainic acid‐induced chronic TLE model, DBS in the MS not only reduced spontaneous seizures, but also improved behavioral performance in novel object recognition. Conclusion DBS in the MS is a promising approach to attenuate TLE probably through entrainment of the hippocampal theta rhythm, which may be therapeutically significant for refractory TLE treatment.
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Affiliation(s)
- Ying Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Yating Shen
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xianhui Cai
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Jie Yu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Cong Chen
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Bei Tan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Na Tan
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Heming Cheng
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xiang Fan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaohua Wu
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Jinggen Liu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shuang Wang
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
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39
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Lenck-Santini PP, Sakkaki S. Alterations of Neuronal Dynamics as a Mechanism for Cognitive Impairment in Epilepsy. Curr Top Behav Neurosci 2021; 55:65-106. [PMID: 33454922 DOI: 10.1007/7854_2020_193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Epilepsy is commonly associated with cognitive and behavioral deficits that dramatically affect the quality of life of patients. In order to identify novel therapeutic strategies aimed at reducing these deficits, it is critical first to understand the mechanisms leading to cognitive impairments in epilepsy. Traditionally, seizures and epileptiform activity in addition to neuronal injury have been considered to be the most significant contributors to cognitive dysfunction. In this review we however highlight the role of a new mechanism: alterations of neuronal dynamics, i.e. the timing at which neurons and networks receive and process neural information. These alterations, caused by the underlying etiologies of epilepsy syndromes, are observed in both animal models and patients in the form of abnormal oscillation patterns in unit firing, local field potentials, and electroencephalogram (EEG). Evidence suggests that such mechanisms significantly contribute to cognitive impairment in epilepsy, independently of seizures and interictal epileptiform activity. Therefore, therapeutic strategies directly targeting neuronal dynamics rather than seizure reduction may significantly benefit the quality of life of patients.
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Affiliation(s)
- Pierre-Pascal Lenck-Santini
- Aix-Marseille Université, INSERM, INMED, Marseille, France. .,Department of Neurological sciences, University of Vermont, Burlington, VT, USA.
| | - Sophie Sakkaki
- Department of Neurological sciences, University of Vermont, Burlington, VT, USA.,Université de. Montpellier, CNRS, INSERM, IGF, Montpellier, France
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40
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Joshi S, Goodkin HP. The Need to Intervene Before Time Point 2: Evidence From Clinical and Animal Data That Status Epilepticus Damages the Brain. J Clin Neurophysiol 2020; 37:375-380. [PMID: 32890057 DOI: 10.1097/wnp.0000000000000711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Status epilepticus, a condition characterized by abnormally prolonged seizures, has the potential to cause irreversible, structural or functional, injury to the brain. Unfavorable consequences of these seizures include mortality, the risk of developing epilepsy, and cognitive impairment. We highlight key findings of clinical and laboratory studies that have provided insights into aspects of cell death, and anatomical and functional alterations triggered by status epilepticus that support the need to intervene before time point 2, the time after which the risk of these long-term consequences increases.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, UVA Health, Charlottesville, Virginia, U.S.A
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Mihály I, Orbán-Kis K, Gáll Z, Berki ÁJ, Bod RB, Szilágyi T. Amygdala Low-Frequency Stimulation Reduces Pathological Phase-Amplitude Coupling in the Pilocarpine Model of Epilepsy. Brain Sci 2020; 10:brainsci10110856. [PMID: 33202818 PMCID: PMC7696538 DOI: 10.3390/brainsci10110856] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/31/2020] [Accepted: 11/11/2020] [Indexed: 02/07/2023] Open
Abstract
Temporal-lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy and warrants the development of new therapies, such as deep-brain stimulation (DBS). DBS was applied to different brain regions for patients with epilepsy; however, the mechanisms of action are not fully understood. Therefore, we tried to characterize the effect of amygdala DBS on hippocampal electrical activity in the lithium-pilocarpine model in male Wistar rats. After status epilepticus (SE) induction, seizure patterns were determined based on continuous video recordings. Recording electrodes were inserted in the left and right hippocampus and a stimulating electrode in the left basolateral amygdala of both Pilo and age-matched control rats 10 weeks after SE. Daily stimulation protocol consisted of 4 × 50 s stimulation trains (4-Hz, regular interpulse interval) for 10 days. The hippocampal electroencephalogram was analyzed offline: interictal epileptiform discharge (IED) frequency, spectral analysis, and phase-amplitude coupling (PAC) between delta band and higher frequencies were measured. We found that the seizure rate and duration decreased (by 23% and 26.5%) and the decrease in seizure rate correlated negatively with the IED frequency. PAC was elevated in epileptic animals and DBS reduced the pathologically increased PAC and increased the average theta power (25.9% ± 1.1 vs. 30.3% ± 1.1; p < 0.01). Increasing theta power and reducing the PAC could be two possible mechanisms by which DBS may exhibit its antiepileptic effect in TLE; moreover, they could be used to monitor effectiveness of stimulation.
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Affiliation(s)
- István Mihály
- Department of Physiology, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, 540142 Târgu Mureș, Romania; (K.O.-K.); (Á.-J.B.); (R.-B.B.), (T.S.)
- Correspondence: ; Tel.: +40-749-768-257
| | - Károly Orbán-Kis
- Department of Physiology, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, 540142 Târgu Mureș, Romania; (K.O.-K.); (Á.-J.B.); (R.-B.B.), (T.S.)
| | - Zsolt Gáll
- Department of Pharmacology and Clinical Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, 540142 Târgu Mureș, Romania;
| | - Ádám-József Berki
- Department of Physiology, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, 540142 Târgu Mureș, Romania; (K.O.-K.); (Á.-J.B.); (R.-B.B.), (T.S.)
| | - Réka-Barbara Bod
- Department of Physiology, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, 540142 Târgu Mureș, Romania; (K.O.-K.); (Á.-J.B.); (R.-B.B.), (T.S.)
| | - Tibor Szilágyi
- Department of Physiology, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Târgu Mureș, 540142 Târgu Mureș, Romania; (K.O.-K.); (Á.-J.B.); (R.-B.B.), (T.S.)
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Hao W, Liu S, Liu H, Mu X, Chen K, Xin Q, Zhang XD. In Vivo Neuroelectrophysiological Monitoring of Atomically Precise Au 25 Clusters at an Ultrahigh Injected Dose. ACS OMEGA 2020; 5:24537-24545. [PMID: 33015471 PMCID: PMC7528291 DOI: 10.1021/acsomega.0c03005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/04/2020] [Indexed: 05/14/2023]
Abstract
Atomically precise Au25(SG)18 clusters have shown great promise in near-infrared II cerebrovascular imaging, X-ray imaging, and cancer radiotherapy due to their high atomic number, unique molecular-like electronic structure, and renal clearable properties. Therefore, it is important to study the in vivo toxicity of Au25 clusters. Unfortunately, previous toxicological investigations focused on low injected doses (<100 mg kg-1) and routine research methods, such as blood chemistry and biochemistry, which cannot reflect neurotoxicity or tiny changes in neural activity. In this work, in vivo neuroelectrophysiology of Au25 clusters at ultrahigh injected doses (200, 300, and 500 mg kg-1) was investigated. Local field potential showed that the Au25-treated mice showed a spike in delta rhythm and moved to lower frequency over time. The power spectrum showed a 38.3% reduction in the peak value at 10 h post-injection of Au25 clusters compared with 3 h post-injection, which gradually became close to the normal level, indicating no permanent damage to the nervous system. Moreover, no significant structural changes were found in both neurons and glial cells at the histological level. These results of in vivo neuroelectrophysiology will encourage scientists to make more exciting discoveries on nervous system diseases by employing Au25 clusters even at ultrahigh injected doses.
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Affiliation(s)
- Wenting Hao
- Tianjin
International Joint Research Center for Neural Engineering, Academy
of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Shuangjie Liu
- Tianjin
International Joint Research Center for Neural Engineering, Academy
of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Haile Liu
- Tianjin
Key Laboratory of Low Dimensional Materials Physics and Preparing
Technology, Institute of Advanced Materials Physics, School of Sciences, Tianjin University, Tianjin 300350, China
| | - Xiaoyu Mu
- Tianjin
Key Laboratory of Low Dimensional Materials Physics and Preparing
Technology, Institute of Advanced Materials Physics, School of Sciences, Tianjin University, Tianjin 300350, China
| | - Ke Chen
- Tianjin
Key Laboratory of Low Dimensional Materials Physics and Preparing
Technology, Institute of Advanced Materials Physics, School of Sciences, Tianjin University, Tianjin 300350, China
| | - Qi Xin
- Tianjin
International Joint Research Center for Neural Engineering, Academy
of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
- Department
of Pathology, Tianjin Third Central Hospital, Tianjin Key Laboratory
of Extracorporeal Life Support for Critical Diseases, Tianjin Third Central Hospital affiliated to Nankai University, Tianjin 300170, China
| | - Xiao-Dong Zhang
- Tianjin
International Joint Research Center for Neural Engineering, Academy
of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
- Tianjin
Key Laboratory of Low Dimensional Materials Physics and Preparing
Technology, Institute of Advanced Materials Physics, School of Sciences, Tianjin University, Tianjin 300350, China
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43
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Li JY, Kuo TBJ, Hung CT, Yang CCH. Voluntary exercise enhances hippocampal theta rhythm and cognition in the rat. Behav Brain Res 2020; 399:112916. [PMID: 32949643 DOI: 10.1016/j.bbr.2020.112916] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 12/14/2022]
Abstract
Regular exercise promotes learning and memory functions. Theta activity is known to relate to various cognitive functions. An increase in theta power may be related to higher cognitive functioning and learning functions. However, evidence is lacking to directly confirm that exercise training can increase the theta activity and promote various cognitive functions simultaneously. We hypothesize that long-term voluntary exercise increases the activity of hippocampal theta rhythm and enhances memory behavior. We used the voluntary wheel running model and a training period of 8 weeks. We started the training when the rats were 12 weeks old. Before and after intervention, we performed a 24 -h electrophysiological recording and 8-arm radial maze test to analyze the hippocampal theta rhythm in awake stage, and spatial memory functions. We discovered that middle to high range frequency (6.5-12 Hz) of theta power was increased after exercise intervention. In addition, the working memory error of 8-arm radial maze test in the exercise group decreased significantly after the 8 weeks of treatment, and these reductions were negatively correlated with hippocampal theta activity. Our results demonstrate that 8-weeks voluntary exercise increases both hippocampal theta amplitude and spatial memory in the rats.
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Affiliation(s)
- Jia-Yi Li
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan; Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Terry B J Kuo
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Brain Research Center, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
| | - Chang-Tsen Hung
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Cheryl C H Yang
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Brain Research Center, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.
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44
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Soltani Zangbar H, Ghadiri T, Vafaee MS, Ebrahimi Kalan A, Karimipour M, Fallahi S, Ghorbani M, Shahabi P. A potential entanglement between the spinal cord and hippocampus: Theta rhythm correlates with neurogenesis deficiency following spinal cord injury in male rats. J Neurosci Res 2020; 98:2451-2467. [DOI: 10.1002/jnr.24719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/02/2020] [Accepted: 08/08/2020] [Indexed: 01/12/2023]
Affiliation(s)
- Hamid Soltani Zangbar
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
- Aging Research Institute Tabriz University of Medical Sciences Tabriz Iran
- Neurosciences Research Center (NSRC) Tabriz University of Medical Sciences Tabriz Iran
| | - Tahereh Ghadiri
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | | | - Abbas Ebrahimi Kalan
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | - Mohammad Karimipour
- Department of Applied Cell Sciences Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | - Solmaz Fallahi
- Department of Physiology Faculty of Medicine Tabriz University of Medical Sciences Tabriz Iran
| | - Meysam Ghorbani
- Department of Physiology Faculty of Medicine Tabriz University of Medical Sciences Tabriz Iran
| | - Parviz Shahabi
- Aging Research Institute Tabriz University of Medical Sciences Tabriz Iran
- Neurosciences Research Center (NSRC) Tabriz University of Medical Sciences Tabriz Iran
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45
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Grosser S, Buck N, Braunewell KH, Gilling KE, Wozny C, Fidzinski P, Behr J. Loss of Long-Term Potentiation at Hippocampal Output Synapses in Experimental Temporal Lobe Epilepsy. Front Mol Neurosci 2020; 13:143. [PMID: 32982687 PMCID: PMC7484482 DOI: 10.3389/fnmol.2020.00143] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/13/2020] [Indexed: 11/24/2022] Open
Abstract
Patients suffering from temporal lobe epilepsy (TLE) show severe problems in hippocampus dependent memory consolidation. Memory consolidation strongly depends on an intact dialog between the hippocampus and neocortical structures. Deficits in hippocampal signal transmission are known to provoke disturbances in memory formation. In the present study, we investigate changes of synaptic plasticity at hippocampal output structures in an experimental animal model of TLE. In pilocarpine-treated rats, we found suppressed long-term potentiation (LTP) in hippocampal and parahippocampal regions such as the subiculum and the entorhinal cortex (EC). Subsequently we focused on the subiculum, serving as the major relay station between the hippocampus proper and downstream structures. In control animals, subicular pyramidal cells express different forms of LTP depending on their intrinsic firing pattern. In line with our extracellular recordings, we could show that LTP could only be induced in a minority of subicular pyramidal neurons. We demonstrate that a well-characterized cAMP-dependent signaling pathway involved in presynaptic forms of LTP is perturbed in pilocarpine-treated animals. Our findings suggest that in TLE, disturbances of synaptic plasticity may influence the information flow between the hippocampus and the neocortex.
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Affiliation(s)
- Sabine Grosser
- Institute of Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Nadine Buck
- Department of Anesthesiology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Karl-Heinz Braunewell
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Kate E Gilling
- Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Christian Wozny
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Faculty of Science, University of Strathclyde, Glasgow, United Kingdom
| | - Pawel Fidzinski
- Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Joachim Behr
- Department of Psychiatry and Psychotherapy, Brandenburg Medical School, Neuruppin, Germany.,Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Aging Alters Olfactory Bulb Network Oscillations and Connectivity: Relevance for Aging-Related Neurodegeneration Studies. Neural Plast 2020; 2020:1703969. [PMID: 32774353 PMCID: PMC7396091 DOI: 10.1155/2020/1703969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/27/2020] [Accepted: 02/12/2020] [Indexed: 11/18/2022] Open
Abstract
The aging process eventually cause a breakdown in critical synaptic plasticity and connectivity leading to deficits in memory function. The olfactory bulb (OB) and the hippocampus, both regions of the brain considered critical for the processing of odors and spatial memory, are commonly affected by aging. Using an aged wild-type C57B/6 mouse model, we sought to define the effects of aging on hippocampal plasticity and the integrity of cortical circuits. Specifically, we measured the long-term potentiation of high-frequency stimulation (HFS-LTP) at the Shaffer-Collateral CA1 pyramidal synapses. Next, local field potential (LFP) spectra, phase-amplitude theta-gamma coupling (PAC), and connectivity through coherence were assessed in the olfactory bulb, frontal and entorhinal cortices, CA1, and amygdala circuits. The OB of aged mice showed a significant increase in the number of histone H2AX-positive neurons, a marker of DNA damage. While the input-output relationship measure of basal synaptic activity was found not to differ between young and aged mice, a pronounced decline in the slope of field excitatory postsynaptic potential (fEPSP) and the population spike amplitude (PSA) were found in aged mice. Furthermore, aging was accompanied by deficits in gamma network oscillations, a shift to slow oscillations, reduced coherence and theta-gamma PAC in the OB circuit. Thus, while the basal synaptic activity was unaltered in older mice, impairment in hippocampal synaptic transmission was observed only in response to HFS. However, age-dependent alterations in neural network appeared spontaneously in the OB circuit, suggesting the neurophysiological basis of synaptic deficits underlying olfactory processing. Taken together, the results highlight the sensitivity and therefore potential use of LFP quantitative network oscillations and connectivity at the OB level as objective electrophysiological markers that will help reveal specific dysfunctional circuits in aging-related neurodegeneration studies.
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47
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Li JY, Kuo TBJ, Yang CCH. Behaviour consistency is a sensitive tool for distinguishing the effects of aging on physical activity. Behav Brain Res 2020; 389:112619. [PMID: 32348871 DOI: 10.1016/j.bbr.2020.112619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/24/2020] [Accepted: 03/15/2020] [Indexed: 11/16/2022]
Abstract
We attempted to establish a novel parameter of behaviour consistency to help determine the effect of age on physical activity. Using the speed of movement to quantify behaviour might not be sufficient to determine this effect. The slowing of motor activities that occurs with aging is related to the decline of the aging brain. Previous studies have found different running-related hippocampal theta rhythm responses in the aging and exercise model. Therefore, we hypothesized that a familiarity with the environment and physical strength affect behavioural consistency in rats during running exercises. For this study, we used a treadmill and 30-minute running test at constant speeds and compared changes in the triaxial accelerometer and hippocampal theta rhythm between adult and middle-aged rats. No significant differences in RR intervals, mean cross-correlations (MCCs), or the proportion of good correlation coefficient (PGCC) were observed between adult and middle-aged rats in awake states before running on the treadmill. The root mean square (RMS) of the triaxial acceleration vectors in middle-aged rats was higher than that in adult rats. In the treadmill running tests, the RMS observed in middle-aged rats was significantly lower than that observed in adult rats. MCC and PGCC, which indicate movement consistencies, were significantly higher in middle-aged rats than they were in adult rats during the entire running test. However, only the RMS of the adult rats showed a negative correlation with exercise duration. Both MCC and PGCC were positively correlated with exercise duration. By contrast, a similar phenomenon was not found in the changes or differences in hippocampal theta rhythms between these two groups. Therefore, we consider that the MCC and PGCC could distinguish age-related movement differences and indicate coordination/adaptation during exercise. Changes in physical activity and alterations in the hippocampal theta rhythm were not different between the groups.
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Affiliation(s)
- Jia-Yi Li
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan; Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Terry B J Kuo
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Brain Research Center, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Digital Medicine Center, National Yang-Ming University, Taipei, Taiwan.
| | - Cheryl C H Yang
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Brain Research Center, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.
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48
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Xing H, Xu S, Xie X, Wang Y, Lu C, Han X. Levetiracetam induction of theta frequency oscillations in rodent hippocampus in vitro. Can J Physiol Pharmacol 2020; 98:725-732. [PMID: 32516556 DOI: 10.1139/cjpp-2019-0727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Levetiracetam (LEV) has been demonstrated to improve cognitive function. Hippocampal theta rhythm (4-12 Hz) is associated with a variety of cognitively related behaviors, such as exploration in both humans and animal models. We investigated the effects of LEV on the theta rhythm in the rat hippocampal CA3 in hippocampal slices in vitro. We found that LEV increased the theta power in a dose-dependent manner. The increase in theta power can be blocked by GABAA receptor (GABAAR) or NMDA receptor (NMDAR) antagonists but not by AMPA receptor antagonist, indicating the involvement of GABAAR and NMDAR in the induction of theta activity. Interestingly, LEV enhancement of theta power can be also blocked by taurine or GABA-A agonist THIP, indicating that LEV induction of theta may be related to the indirect boosting of GABA action via reduction of extrasynaptic GABAAR activation. Furthermore, the increased theta power can be partially reduced by the mACh receptor (mAChR) antagonist atropine but not by nACh receptor antagonists, suggesting that mAChR activation provides excitatory input into local network responsible for LEV-induced theta. Our study demonstrated that LEV induced a novel theta oscillation in vitro, which may have implications in the treatment of the neuronal disorders with impaired theta oscillation and cognitive function.
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Affiliation(s)
- Hang Xing
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China.,Department of Neurology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, 450000, P.R. China
| | - Sihan Xu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Xin'e Xie
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Yuan Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Chengbiao Lu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Xiong Han
- Department of Neurology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, 450000, P.R. China
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Mohammed HS, Aboul Ezz HS, Zedan A, Ali MA. Electrophysiological and Neurochemical Assessment of Selenium Alone or Combined with Carbamazepine in an Animal Model of Epilepsy. Biol Trace Elem Res 2020; 195:579-590. [PMID: 31444771 DOI: 10.1007/s12011-019-01872-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/18/2019] [Indexed: 11/08/2022]
Abstract
The present study aims to evaluate the efficacy of selenium (Se) alone or combined with carbamazepine (CBZ) against the adverse effects induced by the chemoconvulsant pentylenetetrazole (PTZ) in the cortex of adult male rats. Electrocorticogram (ECoG) and oxidative stress markers were implemented to evaluate the differences between treated and untreated animals. Animals were divided into five groups: control group that received i.p. saline injection, PTZ-treated group that received a single i.p. injection of PTZ (60 mg/kg) for induction of seizures followed by a daily i.p. injection of saline, Se-treated group that received an i.p. injection of sodium selenite (0.3 mg/kg/day) after PTZ administration, CBZ-treated group that received orally CBZ (80 mg/kg/day) after PTZ administration, and combination (Se plus CBZ)-treated group that received an oral administration of CBZ (80 mg/kg/day) followed by an i.p. injection of sodium selenite (0.3 mg/kg/day) after PTZ administration. Quantitative analyses of the ECoG indices and the neurochemical parameters revealed that Se and CBZ have mitigated the adverse effects induced by PTZ. The main results were decrease in the number of epileptic spikes, restoring the normal distribution of slow and fast ECoG frequencies and attenuation of most of the oxidative stress markers. However, there was an increase in lipid perioxidation marker in combined treatment of CBZ and Se. The electrophysiological and neurochemical data proved the potential of these techniques in evaluating the treatment's efficiency and suggest that supplementation of Se with antiepileptic drugs (AEDs) may be beneficial in ameliorating most of the alterations induced in the brain as a result of seizure insults and could be recommended as an adjunct therapy with AEDs.
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Affiliation(s)
- Haitham S Mohammed
- Biophysics Department, Faculty of Science, Cairo University, Giza, Egypt.
| | - Heba S Aboul Ezz
- Zoology Department, Faculty of Science, Cairo University, Giza, Egypt
| | - Asmaa Zedan
- Biophysics Department, Faculty of Science, Cairo University, Giza, Egypt
| | - Maha A Ali
- Biophysics Department, Faculty of Science, Cairo University, Giza, Egypt
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50
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Lambert I, Tramoni-Negre E, Lagarde S, Roehri N, Giusiano B, Trebuchon-Da Fonseca A, Carron R, Benar CG, Felician O, Bartolomei F. Hippocampal Interictal Spikes during Sleep Impact Long-Term Memory Consolidation. Ann Neurol 2020; 87:976-987. [PMID: 32279329 DOI: 10.1002/ana.25744] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 03/11/2020] [Accepted: 04/04/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Non-rapid eye movement (NREM) sleep is supposed to play a key role in long-term memory consolidation transferring information from hippocampus to neocortex. However, sleep also activates epileptic activities in medial temporal regions. This study investigated whether interictal hippocampal spikes during sleep would impair long-term memory consolidation. METHOD We prospectively measured visual and verbal memory performance in 20 patients with epilepsy investigated with stereoelectroencephalography (SEEG) at immediate, 30-minute, and 1-week delays, and studied the correlations between interictal hippocampal spike frequency during waking and the first cycle of NREM sleep and memory performance, taking into account the number of seizures occurring during the consolidation period and other possible confounding factors, such as age and epilepsy duration. RESULTS Retention of verbal memory over 1 week was negatively correlated with hippocampal spike frequency during sleep, whereas no significant correlation was found with hippocampal interictal spikes during waking. No significant result was found for visual memory. Regression tree analysis showed that the number of seizures was the first factor that impaired the verbal memory retention between 30 minutes and 1 week. When the number of seizures was below 5, spike frequency during sleep higher than 13 minutes was associated with impaired memory retention over 1 week. INTERPRETATION Our results show that activation of interictal spikes in the hippocampus during sleep and seizures specifically impair long-term memory consolidation. We hypothesize that hippocampal interictal spikes during sleep interrupt hippocampal-neocortical transfer of information. ANN NEUROL 2020;87:976-987.
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Affiliation(s)
- Isabelle Lambert
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Clinical Neurophysiology, Marseille, France
| | - Eve Tramoni-Negre
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Neurology Neuropsychology, Marseille, France
| | - Stanislas Lagarde
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Clinical Neurophysiology, Marseille, France
| | - Nicolas Roehri
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Bernard Giusiano
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Public Health Department, Marseille, France
| | - Agnès Trebuchon-Da Fonseca
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Clinical Neurophysiology, Marseille, France
| | - Romain Carron
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Functional and Stereotactic Neurosurgery, Marseille, France
| | | | - Olivier Felician
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Neurology Neuropsychology, Marseille, France
| | - Fabrice Bartolomei
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.,APHM, Timone Hospital, Clinical Neurophysiology, Marseille, France
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