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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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Zhang Q, Wang Y, Wang F, Jiang D, Song Y, Yang L, Zhang M, Wang Y, Ruan Y, Fang J, Fei F. Septal stimulation attenuates hippocampal seizure with subregion specificity. Epilepsia Open 2024; 9:1445-1457. [PMID: 38831626 PMCID: PMC11296123 DOI: 10.1002/epi4.12983] [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: 02/22/2024] [Revised: 05/06/2024] [Accepted: 05/18/2024] [Indexed: 06/05/2024] Open
Abstract
OBJECTIVE Deep brain stimulation (DBS) is a promising approach for the treatment of epilepsy. However, the optimal target for DBS and underlying mechanisms are still not clear. Here, we compared the therapeutic effects of DBS on distinct septal subregions, aimed to find the precise targets of septal DBS and related mechanisms for the clinical treatment. METHODS Assisted by behavioral test, electroencephalography (EEG) recording and analyzing, selectively neuronal manipulation and immunohistochemistry, we assessed the effects of DBS on the three septal subregions in kainic acid (KA)-induced mouse seizure model. RESULTS DBS in the medial septum (MS) not only delayed generalized seizure (GS) development, but reduced the severity; DBS in the vertical diagonal band of Broca (VDB) only reduced the severity of GS, while DBS in the horizontal diagonal band of Broca (HDB) subregion showed no anti-seizure effect. Notably, DBS in the MS much more efficiently decreased abnormal activation of hippocampal neurons. EEG spectrum analysis indicated that DBS in the MS and VDB subregions mainly increased the basal hippocampal low-frequency (delta and theta) rhythm. Furthermore, ablation of cholinergic neurons in the MS and VDB subregions blocked the anti-seizure and EEG-modulating effects of septal DBS, suggesting the seizure-alleviating effect of DBS was dependent on local cholinergic neurons. SIGNIFICANCE DBS in the MS and VDB, rather than HDB, attenuates hippocampal seizure by activation of cholinergic neurons-augmented hippocampal delta/theta rhythm. This may be of great therapeutic significance for the clinical treatment of epilepsy with septal DBS. PLAIN LANGUAGE SUMMARY The optical target of deep brain stimulation in the septum is still not clear. This study demonstrated that stimulation in the medial septum and vertical diagonal band of Broca subregions, but not the horizontal diagonal band of Broca, could alleviate hippocampal seizure through cholinergic neurons-augmented hippocampal delta/theta rhythm. This study may shed light on the importance of precise regulation of deep brain stimulation therapy in treating epileptic seizures.
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Affiliation(s)
- Qingyang Zhang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
- Chinese Medicine Plant Essential Oil Zhejiang Engineering Research Center, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Yu Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Fei Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Dongxiao Jiang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Yingjie Song
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Lin Yang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Mengdi Zhang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
- Department of Neurology, The Fourth Affiliated Hospital, School of MedicineZhejiang UniversityYiwuChina
| | - Yeping Ruan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
- Chinese Medicine Plant Essential Oil Zhejiang Engineering Research Center, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Jiajia Fang
- Department of Neurology, The Fourth Affiliated Hospital, School of MedicineZhejiang UniversityYiwuChina
| | - Fan Fei
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
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McNerney MW, Gurkoff GG, Beard C, Berryhill ME. The Rehabilitation Potential of Neurostimulation for Mild Traumatic Brain Injury in Animal and Human Studies. Brain Sci 2023; 13:1402. [PMID: 37891771 PMCID: PMC10605899 DOI: 10.3390/brainsci13101402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/25/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Neurostimulation carries high therapeutic potential, accompanied by an excellent safety profile. In this review, we argue that an arena in which these tools could provide breakthrough benefits is traumatic brain injury (TBI). TBI is a major health problem worldwide, with the majority of cases identified as mild TBI (mTBI). MTBI is of concern because it is a modifiable risk factor for dementia. A major challenge in studying mTBI is its inherent heterogeneity across a large feature space (e.g., etiology, age of injury, sex, treatment, initial health status, etc.). Parallel lines of research in human and rodent mTBI can be collated to take advantage of the full suite of neuroscience tools, from neuroimaging (electroencephalography: EEG; functional magnetic resonance imaging: fMRI; diffusion tensor imaging: DTI) to biochemical assays. Despite these attractive components and the need for effective treatments, there are at least two major challenges to implementation. First, there is insufficient understanding of how neurostimulation alters neural mechanisms. Second, there is insufficient understanding of how mTBI alters neural function. The goal of this review is to assemble interrelated but disparate areas of research to identify important gaps in knowledge impeding the implementation of neurostimulation.
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Affiliation(s)
- M. Windy McNerney
- Mental Illness Research Education and Clinical Center (MIRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA; (M.W.M.); (C.B.)
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gene G. Gurkoff
- Department of Neurological Surgery, and Center for Neuroscience, University of California, Davis, Sacramento, CA 95817, USA;
- Department of Veterans Affairs, VA Northern California Health Care System, Martinez, CA 94553, USA
| | - Charlotte Beard
- Mental Illness Research Education and Clinical Center (MIRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA; (M.W.M.); (C.B.)
- Program in Neuroscience and Behavioral Biology, Emory University, Atlanta, GA 30322, USA
| | - Marian E. Berryhill
- Programs in Cognitive and Brain Sciences, and Integrative Neuroscience, Department of Psychology, University of Nevada, Reno, NV 89557, USA
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Cole ER, Grogan DP, Laxpati NG, Fernandez AM, Skelton HM, Isbaine F, Gutekunst CA, Gross RE. Evidence supporting deep brain stimulation of the medial septum in the treatment of temporal lobe epilepsy. Epilepsia 2022; 63:2192-2213. [PMID: 35698897 DOI: 10.1111/epi.17326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 12/28/2022]
Abstract
Electrical brain stimulation has become an essential treatment option for more than one third of epilepsy patients who are resistant to pharmacological therapy and are not candidates for surgical resection. However, currently approved stimulation paradigms achieve only moderate success, on average providing approximately 75% reduction in seizure frequency and extended periods of seizure freedom in nearly 20% of patients. Outcomes from electrical stimulation may be improved through the identification of novel anatomical targets, particularly those with significant anatomical and functional connectivity to the epileptogenic zone. Multiple studies have investigated the medial septal nucleus (i.e., medial septum) as such a target for the treatment of mesial temporal lobe epilepsy. The medial septum is a small midline nucleus that provides a critical functional role in modulating the hippocampal theta rhythm, a 4-7-Hz electrophysiological oscillation mechanistically associated with memory and higher order cognition in both rodents and humans. Elevated theta oscillations are thought to represent a seizure-resistant network activity state, suggesting that electrical neuromodulation of the medial septum and restoration of theta-rhythmic physiology may not only reduce seizure frequency, but also restore cognitive comorbidities associated with mesial temporal lobe epilepsy. Here, we review the anatomical and physiological function of the septohippocampal network, evidence for seizure-resistant effects of the theta rhythm, and the results of stimulation experiments across both rodent and human studies, to argue that deep brain stimulation of the medial septum holds potential to provide an effective neuromodulation treatment for mesial temporal lobe epilepsy. We conclude by discussing the considerations necessary for further evaluating this treatment paradigm with a clinical trial.
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Affiliation(s)
- Eric R Cole
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | | | - Nealen G Laxpati
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Alejandra M Fernandez
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Henry M Skelton
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Faical Isbaine
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Robert E Gross
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA.,Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
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