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Tavakol S, Kebets V, Royer J, Li Q, Auer H, DeKraker J, Jefferies E, Bernasconi N, Bernasconi A, Helmstaedter C, Arafat T, Armony J, Nathan Spreng R, Caciagli L, Frauscher B, Smallwood J, Bernhardt B. Differential relational memory impairment in temporal lobe epilepsy. Epilepsy Behav 2024; 155:109722. [PMID: 38643660 DOI: 10.1016/j.yebeh.2024.109722] [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: 10/23/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 04/23/2024]
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) is typically associated with pathology of the hippocampus, a key structure involved in relational memory, including episodic, semantic, and spatial memory processes. While it is widely accepted that TLE-associated hippocampal alterations underlie memory deficits, it remains unclear whether impairments relate to a specific cognitive domain or multiple ones. METHODS We administered a recently validated task paradigm to evaluate episodic, semantic, and spatial memory in 24 pharmacoresistant TLE patients and 50 age- and sex-matched healthy controls. We carried out two-way analyses of variance to identify memory deficits in individuals with TLE relative to controls across different relational memory domains, and used partial least squares correlation to identify factors contributing to variations in relational memory performance across both cohorts. RESULTS Compared to controls, TLE patients showed marked impairments in episodic and spatial memory, with mixed findings in semantic memory. Even when additionally controlling for age, sex, and overall cognitive function, between-group differences persisted along episodic and spatial domains. Moreover, age, diagnostic group, and hippocampal volume were all associated with relational memory behavioral phenotypes. SIGNIFICANCE Our behavioral findings show graded deficits across relational memory domains in people with TLE, which provides further insights into the complex pattern of cognitive impairment in the condition.
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Affiliation(s)
- Shahin Tavakol
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Valeria Kebets
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Jessica Royer
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Qiongling Li
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Hans Auer
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Jordan DeKraker
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | | | - Neda Bernasconi
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Andrea Bernasconi
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | | | - Thaera Arafat
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Jorge Armony
- Department of Psychiatry, McGill University, Montreal, Canada.
| | - R Nathan Spreng
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Lorenzo Caciagli
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Birgit Frauscher
- ANPHY Lab, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | | | - Boris Bernhardt
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
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Helmstaedter C, Tailby C, Witt JA. Neuropsychology of late-onset epilepsies. Seizure 2024:S1059-1311(24)00078-5. [PMID: 38555201 DOI: 10.1016/j.seizure.2024.03.010] [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: 01/18/2024] [Revised: 03/22/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024] Open
Abstract
In an increasingly ageing society, patients ageing with epilepsy and those with late-onset epilepsies (LOE) represent a challenge for epilepsy care and treatment. Senescence itself bears risks of pathologies which in the form of acute focal damage (e.g. stroke) or slowly progressive degenerative damage can cause seizures and substantial cognitive impairment. There is converging evidence from studies in LOE that cognitive impairments are present from epilepsy onset before treatment is initiated and may even precede the emergence of seizures. This suggests that these impairments (like the seizures) are expressions of the underlying disease. Indeed, both seizures and cognitive impairments can be early indicators of disease conditions which lead to mental decline. Cognitive decline over time poses the challenge of disentangling the interrelation between seizures, treatment effects and underlying disease. This issue must be considered as some of the etiologies for causing neuropsychological decline can be addressed. Medication and active epilepsy can contribute to impairments and their impact may be reversible. Dementia is rare if seizures are what has brought the person to attention, and if this is not accompanied by other slowly developing features (such as cognitive of psychiatric changes). From a neuropsychological point of view choosing the right screening tools or assessments, obtaining the history and timeline of impairments in relation to epilepsy, and most importantly longitudinally following the patients regardless of whether epilepsy is ultimately controlled or not appear essential.
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Affiliation(s)
- C Helmstaedter
- Department of Epileptology, University Hospital Bonn (UKB), 53127 Bonn, Germany.
| | - C Tailby
- Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, 3084, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Clinical Neuropsychology, Austin Hospital, Heidelberg, Victoria, 3084, Australia
| | - J-A Witt
- Department of Epileptology, University Hospital Bonn (UKB), 53127 Bonn, Germany
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Aljishi A, Sherman BE, Huberdeau DM, Obaid S, Khan K, Lamsam L, Zibly Z, Sivaraju A, Turk-Browne NB, Damisah EC. Statistical learning in epilepsy: Behavioral and anatomical mechanisms in the human brain. Epilepsia 2024; 65:753-765. [PMID: 38116686 PMCID: PMC10948305 DOI: 10.1111/epi.17871] [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: 10/15/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 12/21/2023]
Abstract
OBJECTIVE Statistical learning, the fundamental cognitive ability of humans to extract regularities across experiences over time, engages the medial temporal lobe (MTL) in the healthy brain. This leads to the hypothesis that statistical learning (SL) may be impaired in patients with epilepsy (PWE) involving the temporal lobe, and that this impairment could contribute to their varied memory deficits. In turn, studies done in collaboration with PWE, that evaluate the necessity of MTL circuitry through disease and causal perturbations, provide an opportunity to advance basic understanding of SL. METHODS We implemented behavioral testing, volumetric analysis of the MTL substructures, and direct electrical brain stimulation to examine SL across a cohort of 61 PWE and 28 healthy controls. RESULTS We found that behavioral performance in an SL task was negatively associated with seizure frequency irrespective of seizure origin. The volume of hippocampal subfields CA1 and CA2/3 correlated with SL performance, suggesting a more specific role of the hippocampus. Transient direct electrical stimulation of the hippocampus disrupted SL. Furthermore, the relationship between SL and seizure frequency was selective, as behavioral performance in an episodic memory task was not impacted by seizure frequency. SIGNIFICANCE Overall, these results suggest that SL may be hippocampally dependent and that the SL task could serve as a clinically useful behavioral assay of seizure frequency that may complement existing approaches such as seizure diaries. Simple and short SL tasks may thus provide patient-centered endpoints for evaluating the efficacy of novel treatments in epilepsy.
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Affiliation(s)
- Ayman Aljishi
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Psychology, Vanderbilt University, Nashville, TN, 37240, USA
| | - Brynn E. Sherman
- Department of Psychology, Yale University, New Haven, CT 06520, USA
| | | | - Sami Obaid
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Kamren Khan
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Layton Lamsam
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Zion Zibly
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Adithya Sivaraju
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Nicholas B. Turk-Browne
- Department of Psychology, Yale University, New Haven, CT 06520, USA
- Wu Tsai Institute, Yale University, New Haven, CT, 06510, USA
| | - Eyiyemisi C. Damisah
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
- Wu Tsai Institute, Yale University, New Haven, CT, 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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Tian Z, Huang S, Wen S, Zhang Q, Huang K, Gui Y, Hu B, Feng L, Wang Q. Event-related potentials reveal visual episodic memory deficits in patients with temporal lobe epilepsy. Epilepsy Behav 2023; 148:109460. [PMID: 37839245 DOI: 10.1016/j.yebeh.2023.109460] [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: 03/26/2023] [Revised: 07/17/2023] [Accepted: 09/21/2023] [Indexed: 10/17/2023]
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) patients usually suffer from impaired episodic memory (EM), but its underlying electrophysiologic mechanism and impacted cognitive performance are unclear. We aim to investigate the association between episodic memory reserve and physiological measures of memory workload in TLE patients using Event-related potentials (ERP). METHODS A change detection task with image stimuli assesses visual episodic memory. During the memory encoding and decoding phases, the ERP signals were analyzed from twenty-nine TLE patients (twelve with left TLE patients, seventeen with TLE), and thirty healthy controls. Given that EM is a complex process involving many fundamental cognitive processes, the amplitudes and latencies of EM-related ERP (FN400, late positive potential (LPC), and late posterior negativity (LPN)), and the ERP reflecting the fundamental processes (P100, N100, P200, and P300) were calculated. Then we used a three-by-two factorial design on the ERP metrics for interaction and main effects. The correlation analysis among Wechsler Memory Scales-Chinese Revision (WMS-RC) results, behavioral data, and the ERPs was carried out. RESULTS The TLE patients performed worse in WMS-RC and the memory task. The increased P200 and decreased P300 amplitudes were observed in the TLE patients, and LPN was abnormal in only LTLE patients. For EM-related components, differences were observed in both the LTLE and RTLE patients: the lack of the FN400 effect, the lack of the reversed LPC effect, and the reduced FN400. No significant inter-group difference was detected for the latencies of all the ERPs. Additionally, there were significant correlations among WMS-RC scores, behaviors, and some ERP amplitudes. CONCLUSIONS The impaired EM is linked to the increased P200 and decreased P300 amplitudes. LPN seems to be sensitive to left temporal lobe dysfunction. More importantly, the abnormal old or new effects of the FN400 and LPC, and the reduced FN400 amplitude might be associated with the visual EM deficit in the TLE patients. These findings may assist in the deep understanding of the EM disorder and the evaluation of the side effects of antiepileptic drugs.
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Affiliation(s)
- Ziwei Tian
- Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China; University of Chinese Academy of Sciences, Beijing 101408, China; Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China
| | - Sha Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 330000, China
| | - Shirui Wen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 330000, China
| | - Qiong Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 330000, China
| | - Kailing Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 330000, China
| | - Yawei Gui
- Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China; University of Chinese Academy of Sciences, Beijing 101408, China; Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China
| | - Bingliang Hu
- Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China; Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China
| | - Li Feng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 330000, China; Department of Neurology, Xiangya Hospital, Central South University (Jiangxi Branch), Nanchang, Jiangxi 410008, China.
| | - Quan Wang
- Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China; Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China.
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Aljishi A, Sherman BE, Huberdeau DM, Obaid S, Sivaraju A, Turk-Browne NB, Damisah EC. Statistical learning in epilepsy: Behavioral, anatomical, and causal mechanisms in the human brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.538321. [PMID: 37162937 PMCID: PMC10168289 DOI: 10.1101/2023.04.25.538321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Statistical learning, the fundamental cognitive ability of humans to extract regularities across experiences over time, engages the medial temporal lobe in the healthy brain. This leads to the hypothesis that statistical learning may be impaired in epilepsy patients, and that this impairment could contribute to their varied memory deficits. In turn, epilepsy patients provide a platform to advance basic understanding of statistical learning by helping to evaluate the necessity of medial temporal lobe circuitry through disease and causal perturbations. We implemented behavioral testing, volumetric analysis of the medial temporal lobe substructures, and direct electrical brain stimulation to examine statistical learning across a cohort of 61 epilepsy patients and 28 healthy controls. Behavioral performance in a statistical learning task was negatively associated with seizure frequency, irrespective of where seizures originated in the brain. The volume of hippocampal subfields CA1 and CA2/3 correlated with statistical learning performance, suggesting a more specific role of the hippocampus. Indeed, transient direct electrical stimulation of the hippocampus disrupted statistical learning. Furthermore, the relationship between statistical learning and seizure frequency was selective: behavioral performance in an episodic memory task was impacted by structural lesions in the medial temporal lobe and by antiseizure medications, but not by seizure frequency. Overall, these results suggest that statistical learning may be hippocampally dependent and that this task could serve as a clinically useful behavioral assay of seizure frequency distinct from existing neuropsychological tests. Simple and short statistical learning tasks may thus provide patient-centered endpoints for evaluating the efficacy of novel treatments in epilepsy.
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Affiliation(s)
- Ayman Aljishi
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Brynn E. Sherman
- Department of Psychology, Yale University, New Haven, CT 06520, USA
| | | | - Sami Obaid
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Adithya Sivaraju
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Nicholas B. Turk-Browne
- Department of Psychology, Yale University, New Haven, CT 06520, USA
- Wu Tsai Institute, Yale University, New Haven, CT, 06510, USA
| | - Eyiyemisi C. Damisah
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
- Wu Tsai Institute, Yale University, New Haven, CT, 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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Nazarinia D, Karimpour S, Hashemi P, Dolatshahi M. Neuroprotective effects of Royal Jelly (RJ) against pentylenetetrazole (PTZ)-induced seizures in rats by targeting inflammation and oxidative stress. J Chem Neuroanat 2023; 129:102255. [PMID: 36878412 DOI: 10.1016/j.jchemneu.2023.102255] [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: 01/06/2023] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 03/07/2023]
Abstract
Epilepsy is a chronic neurological condition in which inflammation and oxidative stress play a key role in the pathogenesis. Recently, several studies have suggested that Royal Jelly (RJ) has antioxidant effects. Nevertheless, there is no evidence of its effectiveness against epilepsy. Here, we evaluated its neuroprotective effects at different doses (100 and 200 mg/kg) against pentylenetetrazole (PTZ)-induced seizures. Fifty male Wistar rats were randomly divided into five groups: control, PTZ, RJ100 + PTZ, RJ200 + PTZ and RJ100. In order to establish epilepsy model, 45 mg/kg of PTZ was injected intraperitoneally for 10 consecutive days. Seizure parameters were graded based on Racine's 7-point classification. Elevated-plus maze, Y maze and shuttle box tests were carried out to assess anxiety-like behavior, short-term memory, and passive avoidance memory, respectively. We used ELISA technique to measure the expression of the pro-inflammatory cytokines and oxidative stress factors. Also, neuronal loss in the hippocampal CA3 region was determined using Nissl staining. Our findings showed that PTZ-treated rats had more seizure intensity, anxiety-like behavior, memory dysfunction, higher levels of TNF-α, IL-1β, and oxidative markers. RJ could allay seizure severity and duration. It also improved memory function as well as anxiety level. In terms of biochemical assessment, RJ gave rise to a significant decrease in the level of IL-1β, TNF-α and MDA and it restored the activities of GPX and SOD enzymes. Hence, our study shows that RJ contains anti-inflammatory and antioxidative effects which contribute to less neuronal damage in the PTZ-induced epilepsy model.
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Affiliation(s)
- Donya Nazarinia
- Department of Physiology, School of Paramedical Sciences, Dezful University of Medical Sciences, Dezful, Iran.
| | - Sepideh Karimpour
- Department of Physiology, School of Paramedical Sciences, Dezful University of Medical Sciences, Dezful, Iran
| | - Paria Hashemi
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Mojtaba Dolatshahi
- Department of Physiology, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran
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Peplow P, Martinez B. MicroRNAs as potential biomarkers in temporal lobe epilepsy and mesial temporal lobe epilepsy. Neural Regen Res 2023; 18:716-726. [DOI: 10.4103/1673-5374.354510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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8
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Brain single cell transcriptomic profiles in episodic memory phenotypes associated with temporal lobe epilepsy. NPJ Genom Med 2022; 7:69. [PMID: 36446800 PMCID: PMC9709106 DOI: 10.1038/s41525-022-00339-4] [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: 06/14/2022] [Accepted: 11/08/2022] [Indexed: 12/02/2022] Open
Abstract
Memory dysfunction is prevalent in temporal lobe epilepsy (TLE), but little is known about the underlying molecular etiologies. Single-nucleus RNA sequencing technology was used to examine differences in cellular heterogeneity among left (language-dominant) temporal neocortical tissues from patients with TLE with (n = 4) or without (n = 2) impairment in verbal episodic memory. We observed marked cell heterogeneity between memory phenotypes and identified numerous differentially expressed genes across all brain cell types. The most notable differences were observed in glutamatergic (excitatory) and GABAergic (inhibitory) neurons with an overrepresentation of genes associated with long-term potentiation, long-term depression, and MAPK signaling, processes known to be essential for episodic memory formation.
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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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Malkov A, Shevkova L, Latyshkova A, Kitchigina V. Theta and gamma hippocampal-neocortical oscillations during the episodic-like memory test: Impairment in epileptogenic rats. Exp Neurol 2022; 354:114110. [PMID: 35551900 DOI: 10.1016/j.expneurol.2022.114110] [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: 07/06/2021] [Revised: 04/16/2022] [Accepted: 05/05/2022] [Indexed: 11/04/2022]
Abstract
Cortical oscillations in different frequency bands have been shown to be intimately involved in exploration of environment and cognition. Here, the local field potentials in the hippocampus, the medial prefrontal cortex (mPFC), and the medial entorhinal cortex (mEC) were recorded simultaneously in rats during the execution of the episodic-like memory task. The power of theta (~4-10 Hz), slow gamma (~25-50 Hz), and fast gamma oscillations (~55-100 Hz) was analyzed in all structures examined. Particular attention was paid to the theta coherence between three mentioned structures. The modulation of the power of gamma rhythms by the phase of theta cycle during the execution of the episodic-like memory test by rats was also closely studied. Healthy rats and rats one month after kainate-induced status epilepticus (SE) were examined. Paroxysmal activity in the hippocampus (high amplitude interictal spikes), excessive excitability of animals, and the death of hippocampal and dentate granular cells in rats with kainate-evoked SE were observed, which indicated the development of seizure focus in the hippocampus (epileptogenesis). One month after SE, the rats exhibited a specific impairment of episodic memory for the what-where-when triad: unlike healthy rats, epileptogenic SE animals did not identify the objects during the test. This impairment was associated with the changes in the characteristics of theta and gamma rhythms and specific violation of theta coherence and theta/gamma coupling in these structures in comparison with the healthy animals. We believe that these disturbances in the cortical areas play a role in episodic memory dysfunction in kainate-treated animals. These findings can shed light on the mechanisms of cognitive deficit during epileptogenesis.
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Affiliation(s)
- Anton Malkov
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Russia.
| | | | - Alexandra Latyshkova
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Russia
| | - Valentina Kitchigina
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Russia
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Wießner I, Olivieri R, Falchi M, Palhano-Fontes F, Oliveira Maia L, Feilding A, B Araujo D, Ribeiro S, Tófoli LF. LSD, afterglow and hangover: Increased episodic memory and verbal fluency, decreased cognitive flexibility. Eur Neuropsychopharmacol 2022; 58:7-19. [PMID: 35158230 DOI: 10.1016/j.euroneuro.2022.01.114] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/26/2022] [Accepted: 01/29/2022] [Indexed: 12/20/2022]
Abstract
Psychedelics acutely impair cognitive functions, but these impairments decline with growing experiences with psychedelics and microdoses may even exert opposing effects. Given the recent evidence that psychedelics induce neuroplasticity, this explorative study aimed at investigating the potential of psychedelics to sub-acutely change cognition. For this, we applied a randomized, double-blind, placebo-controlled, crossover study with 24 healthy volunteers receiving 50 μg lysergic acid diethylamide (LSD) or an inactive placebo. Sub-acute changes in cognition were measured 24 h after dosing, including memory (Rey-Osterrieth Complex Figure, ROCF; 2D Object-Location Memory Task, OLMT; Rey Auditory-Verbal Learning Test, RAVLT), verbal fluency (phonological; semantic; switch), design fluency (basic; filter; switch), cognitive flexibility (Wisconsin Card Sorting Test, WCST), sustained and switching attention (Trail Making Test, TMT), inhibitory control (Stroop Task) and perceptual reasoning (Block Design Test, BDT). The results show that when compared to placebo and corrected for Body Mass Index (BMI) and abstinence period from psychedelics, LSD sub-acutely improved visuospatial memory (ROCF immediate recall points and percentage, OLMT consolidation percentage) and phonological verbal fluency and impaired cognitive flexibility (WCST: fewer categories achieved; more perseveration, errors and conceptual level responses). In conclusion, the low dose of LSD moderately induced both "afterglow" and "hangover". The improvements in visuospatial memory and phonological fluency suggest that LSD-assisted therapy should be explored as a novel treatment perspective in conditions involving memory and language declines such as brain injury, stroke or dementia.
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Affiliation(s)
- Isabel Wießner
- Department of Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil; Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.
| | - Rodolfo Olivieri
- Department of Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil; Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Marcelo Falchi
- Department of Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil; Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Fernanda Palhano-Fontes
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Lucas Oliveira Maia
- Department of Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil; Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Amanda Feilding
- The Beckley Foundation, Beckley Park, Oxford, United Kingdom
| | - Draulio B Araujo
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Luís Fernando Tófoli
- Department of Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil; Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
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12
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Abstract
GABA is the main inhibitory neurotransmitter in the mammalian central nervous system (CNS) and acts via metabotropic GABAB receptors. Neurodegenerative diseases are a major burden and affect an ever increasing number of humans. The actual therapeutic drugs available are partially effective to slow down the progression of the diseases, but there is a clear need to improve pharmacological treatment thus find alternative drug targets and develop newer pharmaco-treatments. This chapter is dedicated to reviewing the latest evidence about GABAB receptors and their inhibitory mechanisms and pathways involved in the neurodegenerative pathologies.
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Affiliation(s)
- Alessandra P Princivalle
- Department of Bioscience and Chemistry, Biomolecular Research Centre, College of Health, Wellbeing and Life Sciences at Sheffield Hallam University, Sheffield, UK.
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13
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Lee SJ, Beam DE, Schjetnan AGP, Paul LK, Chandravadia N, Reed CM, Chung JM, Ross IB, Valiante TA, Mamelak AN, Rutishauser U. Single-neuron correlate of epilepsy-related cognitive deficits in visual recognition memory in right mesial temporal lobe. Epilepsia 2021; 62:2082-2093. [PMID: 34289113 PMCID: PMC8403636 DOI: 10.1111/epi.17010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/06/2021] [Accepted: 07/06/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Impaired memory is a common comorbidity of refractory temporal lobe epilepsy (TLE) and often perceived by patients as more problematic than the seizures themselves. The objective of this study is to understand what the relationship of these behavioral impairments is to the underlying pathophysiology, as there are currently no treatments for these deficits, and it remains unknown what circuits are affected. METHODS We recorded single neurons in the medial temporal lobes (MTLs) of 62 patients (37 with refractory TLE) who performed a visual recognition memory task to characterize the relationship between behavior, tuning, and anatomical location of memory selective and visually selective neurons. RESULTS Subjects with a seizure onset zone (SOZ) in the right but not left MTL demonstrated impaired ability to recollect as indicated by the degree of asymmetry of the receiver operating characteristic curve. Of the 1973 recorded neurons, 159 were memory selective (MS) and 366 were visually selective (VS) category cells. The responses of MS neurons located within right but not left MTL SOZs were impaired during high-confidence retrieval trials, mirroring the behavioral deficit seen both in our task and in standardized neuropsychological tests. In contrast, responses of VS neurons were unimpaired in both left and right MTL SOZs. Our findings show that neuronal dysfunction within SOZs in the MTL was specific to a functional cell type and behavior, whereas other cell types respond normally even within the SOZ. We show behavioral metrics that detect right MTL SOZ-related deficits and identify a neuronal correlate of this impairment. SIGNIFICANCE Together, these findings show that single-cell responses can be used to assess the causal effects of local circuit disruption by an SOZ in the MTL, and establish a neural correlate of cognitive impairment due to epilepsy that can be used as a biomarker to assess the efficacy of novel treatments.
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Affiliation(s)
- Seung J Lee
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Neurologic Surgery, Mayo Clinic, Jacksonville, FLA, USA
| | - Danielle E Beam
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | | | - Lynn K Paul
- Division of Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Nand Chandravadia
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Chrystal M Reed
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jeffrey M Chung
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ian B Ross
- Department of Neurosurgery, Huntington Memorial Hospital, Pasadena, CA, USA
| | - Taufik A Valiante
- Krembil Neuroscience Centre, University Health Network, Toronto, ON, Canada.,Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Adam N Mamelak
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.,Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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14
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Zhen ZH, Guo MR, Li HM, Guo OY, Zhen JL, Fu J, Tan GJ. Normal and Abnormal Sharp Wave Ripples in the Hippocampal-Entorhinal Cortex System: Implications for Memory Consolidation, Alzheimer's Disease, and Temporal Lobe Epilepsy. Front Aging Neurosci 2021; 13:683483. [PMID: 34262446 PMCID: PMC8273653 DOI: 10.3389/fnagi.2021.683483] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/01/2021] [Indexed: 12/14/2022] Open
Abstract
The appearance of hippocampal sharp wave ripples (SWRs) is an electrophysiological biomarker for episodic memory encoding and behavioral planning. Disturbed SWRs are considered a sign of neural network dysfunction that may provide insights into the structural connectivity changes associated with cognitive impairment in early-stage Alzheimer's disease (AD) and temporal lobe epilepsy (TLE). SWRs originating from hippocampus have been extensively studied during spatial navigation in rodents, and more recent studies have investigated SWRs in the hippocampal-entorhinal cortex (HPC-EC) system during a variety of other memory-guided behaviors. Understanding how SWR disruption impairs memory function, especially episodic memory, could aid in the development of more efficacious therapeutics for AD and TLE. In this review, we first provide an overview of the reciprocal association between AD and TLE, and then focus on the functions of HPC-EC system SWRs in episodic memory consolidation. It is posited that these waveforms reflect rapid network interactions among excitatory projection neurons and local interneurons and that these waves may contribute to synaptic plasticity underlying memory consolidation. Further, SWRs appear altered or ectopic in AD and TLE. These waveforms may thus provide clues to understanding disease pathogenesis and may even serve as biomarkers for early-stage disease progression and treatment response.
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Affiliation(s)
- Zhi-Hang Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Mo-Ran Guo
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - He-Ming Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ou-Yang Guo
- Department of Biology, Boston University, Boston, MA, United States
| | - Jun-Li Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Jian Fu
- Department of Emergency Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Guo-Jun Tan
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
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15
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Using a wearable camera to support everyday memory following brain injury: a single-case study. BRAIN IMPAIR 2021. [DOI: 10.1017/brimp.2021.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractBackground:Wearable cameras have been shown to improve memory in people with hippocampal amnesia and Alzheimer's disease. It is not known whether this benefit extends to people with amnesia of complex or uncertain origin.Method:This case study examined the effect of wearable camera use on memory and occupational performance in a patient with memory loss and complex mental health problems following a severe neurological incident. With the help of his occupational therapist (OT), Mr A used a wearable camera to record a series of eight personally significant events over a 6-week period. During visits from his OT, Mr A was asked to report what he could remember about the events, both before (baseline) and during the review of time-lapsed photographs captured automatically by the camera.Results:The results showed striking improvements in recall while reviewing the photographs, relative to baseline recall, but the additional details recalled during review did not appear to be maintained at later tests, after several days. Across the study period, there were moderate increases in occupational performance, measured using the Canadian Occupational Performance Measure. However, after the study period ended, Mr A ceased to use the wearable camera due to technological difficulty.Conclusion:There was a clear benefit of wearable camera use, but the real-world impact of the technology was limited by the complexity of the system. The results of the study are discussed alongside novel clinical insights and suggestions for developing wearable camera support systems that can be used independently by people with memory problems.
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16
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van Schalkwijk FJ, Gruber WR, Miller LA, Trinka E, Höller Y. Investigating the Effects of Seizures on Procedural Memory Performance in Patients with Epilepsy. Brain Sci 2021; 11:brainsci11020261. [PMID: 33669626 PMCID: PMC7922212 DOI: 10.3390/brainsci11020261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/08/2021] [Accepted: 02/16/2021] [Indexed: 11/16/2022] Open
Abstract
Memory complaints are frequently reported by patients with epilepsy and are associated with seizure occurrence. Yet, the direct effects of seizures on memory retention are difficult to assess given their unpredictability. Furthermore, previous investigations have predominantly assessed declarative memory. This study evaluated within-subject effects of seizure occurrence on retention and consolidation of a procedural motor sequence learning task in patients with epilepsy undergoing continuous monitoring for five consecutive days. Of the total sample of patients considered for analyses (N = 53, Mage = 32.92 ± 13.80 y, range = 18–66 y; 43% male), 15 patients experienced seizures and were used for within-patient analyses. Within-patient contrasts showed general improvements over seizure-free (day + night) and seizure-affected retention periods. Yet, exploratory within-subject contrasts for patients diagnosed with temporal lobe epilepsy (n = 10) showed that only seizure-free retention periods resulted in significant improvements, as no performance changes were observed following seizure-affected retention. These results indicate general performance improvements and offline consolidation of procedural memory during the day and night. Furthermore, these results suggest the relevance of healthy temporal lobe functioning for successful consolidation of procedural information, as well as the importance of seizure control for effective retention and consolidation of procedural memory.
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Affiliation(s)
- Frank J. van Schalkwijk
- Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Department of Neurology, Paracelsus Medical University, 5020 Salzburg, Austria; (F.J.v.S.); (E.T.)
| | - Walter R. Gruber
- Centre for Cognitive Neuroscience (CCNS), Department of Psychology, University of Salzburg, 5020 Salzburg, Austria;
| | - Laurie A. Miller
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital and Central Medical School, University of Sydney, Camperdown, Sydney, NSW 2050, Australia;
- ARC Centre of Excellence in Cognition and Its Disorders, University of Sydney, Camperdown, Sydney, NSW 2006, Australia
| | - Eugen Trinka
- Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Department of Neurology, Paracelsus Medical University, 5020 Salzburg, Austria; (F.J.v.S.); (E.T.)
| | - Yvonne Höller
- Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Department of Neurology, Paracelsus Medical University, 5020 Salzburg, Austria; (F.J.v.S.); (E.T.)
- Faculty of Psychology, University of Akureyri, 600 Akureyri, Iceland
- Correspondence: ; Tel.: +35-044-608-576
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17
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Barrett Jones S, A Miller L, Kleitman S, Nikpour A, Lah S. Semantic and episodic memory in adults with temporal lobe epilepsy. APPLIED NEUROPSYCHOLOGY-ADULT 2021; 29:1352-1361. [PMID: 33595395 DOI: 10.1080/23279095.2021.1876692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The primary aims were to (1) identify the factor structure of tests thought to measure semantic and episodic memory and (2) examine whether patterns of impairment would show a double dissociation between these two memory systems at an individual level in patients with temporal lobe epilepsy (TLE). The secondary aim was to explore the impact of epilepsy-related variables on performance. This retrospective study involved a cohort of 54 adults who had been diagnosed with TLE and had undergone a neuropsychological assessment that included four memory tests traditionally used to measure either semantic memory (picture naming, animal fluency) or episodic memory (story recall, word list recall) at a single epilepsy surgery center in Australia. Principal component analysis revealed two factors albeit with unexpected loadings. Picture naming and story recall loaded on one factor. Animal fluency and word list recall loaded on another factor. There was no evidence of a double dissociation between semantic and episodic memory at an individual level. Left hemisphere seizure focus and early age of seizure onset related to worse performance on word list recall, picture naming and animal fluency, respectively. Our study highlights the importance of caution when interpreting the results of neuropsychological assessments, as not all putative tests of semantic and episodic memory may necessarily be measuring the same construct. Future directions for research are also considered.
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Affiliation(s)
| | - Laurie A Miller
- Central Clinical School, University of Sydney, New South Wales, Australia
| | - Sabina Kleitman
- School of Psychology, University of Sydney, Sydney, Australia
| | - Armin Nikpour
- Central Clinical School, University of Sydney, New South Wales, Australia.,University of Sydney, Sydney, Australia
| | - Suncica Lah
- School of Psychology, University of Sydney, Sydney, Australia
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18
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Elbanhawy I, Fahmy EM, Sharaf S, Ismail RS, Elmehdawy K. Association between serum apolipoprotein E and cognitive functions in Egyptian patients with temporal lobe epilepsy. Acta Neurol Belg 2021; 121:161-166. [PMID: 31197659 DOI: 10.1007/s13760-019-01167-7] [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: 05/29/2018] [Accepted: 06/06/2019] [Indexed: 10/26/2022]
Abstract
Memory, cognition and visuospatial aspects of temporal lobe epilepsy (TLE) have not been fully analyzed yet. From among the huge growing population of circulating apoproteins analyzed in TLE, apolipoprotein E (APOE) was discovered; however, its role in TLE has not been fully elucidated yet. This study was designed to investigate the relation between the serum level of APOE and cognition in TLE patients. Sixty-five subjects (35 TLE patients and 30 healthy matched controls) were included. Evaluation of cognitive functions was done using Addenbrooke's Cognitive Examination Revised (ACE-R) scale. Serum APOE level was measured by ELISA. The mean total score, memory and visuospatial scores of ACE-R were significantly lower in TLE patients compared to healthy subjects. The mean total score and memory score of ACE-R were significantly lower in seizures originating from mesial temporal lobe (MTL) and left temporal lobe seizures. Serum APOE levels were significantly higher in TLE patients compared to healthy subjects. Serum APOE levels significantly negatively correlated with total score, memory, and visuospatial ability scores of ACE-R. Serum APOE was significantly higher in MTL seizures compared to lateral lobe seizures and in left temporal lobe seizures compared to right temporal seizures. Memory and visuospatial aspects were significantly affected in TLE patients. So, the serum APOE level can possibly contribute to cognitive dysfunction in such patients.
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19
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Helmstaedter C, Hansen N, Leelaarporn P, Schwing K, Oender D, Widman G, Racz A, Surges R, Becker A, Witt JA. Specific B- and T-cell populations are associated with cognition in patients with epilepsy and antibody positive and negative suspected limbic encephalitis. J Neurol 2021; 268:455-466. [PMID: 32816110 PMCID: PMC7880943 DOI: 10.1007/s00415-020-10158-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/30/2020] [Accepted: 08/10/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Neuropsychological impairments are major symptoms of autoimmune limbic encephalitis (LE) epilepsy patients. In LE epilepsy patients with an autoimmune response against intracellular antigens as well as in antibody-negative patients, the antibody findings and magnetic resonance imaging pathology correspond poorly to the clinical features. Here, we evaluated whether T- and B-cells are linked to cognitive impairment in these groups. METHODS In this cross-sectional, observational, case-controlled study, we evaluated 106 patients with adult-onset epilepsies with a suspected autoimmune etiology. We assessed verbal and visual memory, executive function, and mood in relation to the presence or absence of known auto-antibodies, and regarding T- and B-cell activity as indicated by flow cytometry (fluorescence-activated cell sorting = FACS, peripheral blood = PB and cerebrospinal fluid = CSF). RESULTS 56% of the patients were antibody-negative. In the other patients, auto-antibodies were directed against intracellular antigens (GAD65, paraneoplastic: 38%), or cellular surface antigens (LGI1/CASPR2/NMDA-R: 6%). Excluding LGI1/CASPR2/NMDA-R, the groups with and without antibodies did not differ in disease features, cognition, or mood. CD4+ T-cells and CD8+ T-cells in blood and CD4+ T-cells in CSF were prominent in the auto-antibody positive group. Regression analyses indicated the role education, drug load, amygdala and/or hippocampal pathology, and CD4+ T-cells play in verbal memory and executive function. Depressed mood revealed no relation to flow cytometry results. CONCLUSION Our results indicate a link between T- and B-cell activity and cognition in epilepsy patients with suspected limbic encephalitis, thus suggesting that flow cytometry results can provide an understanding of cognitive impairment in LE patients with autoantibodies against intracellular antigens.
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Affiliation(s)
- Christoph Helmstaedter
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany.
| | - Niels Hansen
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Von-Siebold-Str. 5, 37075, Göttingen, Germany
| | - Pitshaporn Leelaarporn
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
| | - Kerstin Schwing
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
| | - Demet Oender
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
| | - Guido Widman
- SEIN Epilepsy Center, Hemsteede, The Netherlands
| | - Attila Racz
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
| | - Rainer Surges
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
| | - Albert Becker
- Department of Neuropathology, University Hospital, Bonn, Germany
| | - Juri-Alexander Witt
- Department of Epileptology, University Hospital Bonn, Building 83 Venusberg-Campus 1, 53127, Bonn, Germany
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20
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Ramm M, Sundermann B, Gomes CA, Möddel G, Langenbruch L, Nayyeri MD, Young P, Pfleiderer B, Krebs RM, Axmacher N. Probing the relevance of the hippocampus for conflict-induced memory improvement. Neuroimage 2020; 226:117563. [PMID: 33189928 PMCID: PMC7836234 DOI: 10.1016/j.neuroimage.2020.117563] [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: 06/08/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 12/05/2022] Open
Abstract
The hippocampus plays a key role for episodic memory. In addition, a small but growing number of studies has shown that it also contributes to the resolution of response conflicts. It is less clear how these two functions are related, and how they are affected by hippocampal lesions in patients with mesial temporal lobe epilepsy (MTLE). Previous studies suggested that conflict stimuli might be better remembered, but whether the hippocampus is critical for supporting this interaction between conflict processing and memory formation is unknown. Here, we tested 19 patients with MTLE due to hippocampal sclerosis and 19 matched healthy controls. Participants performed a face-word Stroop task during functional magnetic resonance imaging (fMRI) followed by a recognition task for the faces. We tested whether memory performance and activity in brain regions implicated in long-term memory were modulated by conflict during encoding, and whether this differed between MTLE patients and controls. In controls, we largely replicated previous findings of improved memory for conflict stimuli. While MTLE patients showed response time slowing during conflict trials as well, they did not exhibit a memory benefit. In controls, neural activity of conflict resolution and memory encoding interacted within a hippocampal region of interest. Here, left hippocampal recruitment was less efficient for memory performance in incongruent trials than in congruent trials, suggesting an intrahippocampal competition for limited resources. They also showed an involvement of precuneus and posterior cingulate cortex during conflict resolution. Both effects were not observed in MTLE patients, where activation of the precuneus and posterior cingulate cortex instead predicted later memory. Further research is needed to find out whether our findings reflect widespread functional reorganization of the episodic memory network due to hippocampal dysfunction.
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Affiliation(s)
- Markus Ramm
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; Neurobiology and Genetics of Behavior, Department of Psychology and Psychotherapy, Centre for Biomedical Education and Research (ZBAF), Witten/Herdecke University, Witten, Germany
| | - Benedikt Sundermann
- Institute of Clinical Radiology, Medical Faculty - University of Muenster - and University Hospital Muenster, Muenster, Germany; Institute of Radiology and Neuroradiology, University of Oldenburg, Evangelisches Krankenhaus, Medical Campus, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Carlos Alexandre Gomes
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Gabriel Möddel
- Department of Neurology with Institute of Translational Neurology, University Hospital Muenster, Muenster, Germany
| | - Lisa Langenbruch
- Department of Neurology with Institute of Translational Neurology, University Hospital Muenster, Muenster, Germany
| | - Mahboobeh Dehghan Nayyeri
- Institute of Clinical Radiology, Medical Faculty - University of Muenster - and University Hospital Muenster, Muenster, Germany; Department of Psychosomatic Medicine and Psychotherapy, LVR Clinic, Medical Faculty of the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Peter Young
- Department of Neurology, Medical Park Bad Feilnbach Reithofpark, Bad Feilnbach, Germany
| | - Bettina Pfleiderer
- Institute of Clinical Radiology, Medical Faculty - University of Muenster - and University Hospital Muenster, Muenster, Germany
| | - Ruth M Krebs
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Nikolai Axmacher
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
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21
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Helmstaedter C, Sadat-Hossieny Z, Kanner AM, Meador KJ. Cognitive disorders in epilepsy II: Clinical targets, indications and selection of test instruments. Seizure 2020; 83:223-231. [PMID: 33172763 DOI: 10.1016/j.seizure.2020.09.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/26/2022] Open
Abstract
This is the second of two narrative reviews on cognitive disorders in epilepsy (companion manuscript: Cognitive disorders in epilepsy I: Clinical experience, real-world evidence and recommendations). Its focus is on the clinical targets, indications, and the selection of neuropsychological test instruments. Cognitive assessment has become an essential tool for the diagnosis and outcome control in the clinical management of epilepsy. The diagnostics of basic and higher brain functions can provide valuable information on lateralized and localized brain dysfunctions associated with epilepsy, its underlying pathologies and treatment. In addition to the detection or verification of deficits, neuropsychology reveals the patient's cognitive strengths and, thus, information about the patient reserve capacities for functional restitution and compensation. Neuropsychology is an integral part of diagnostic evaluations mainly in the context of epilepsy surgery to avoid new or additional damage to preexisting neurocognitive impairments. In addition and increasingly, neuropsychology is being used as a tool for monitoring of the disease and its underlying pathologies, and it is suited for the quality and outcome control of pharmacological or other non-invasive medical intervention. This narrative review summarizes the present state of neuropsychological assessments in epilepsy, reveals diagnostic gaps, and shows the great need for education, homogenization, translation and standardization of instruments.
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Affiliation(s)
- C Helmstaedter
- University Clinic Bonn, Department of Epileptology, Germany.
| | - Z Sadat-Hossieny
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, 213 Quarry Road, MC 5979, CA, 94304, USA
| | - A M Kanner
- University of Miami Health System, Uhealth Neurology, 1150 NW 14th St #609, Miami, FL 33136, USA
| | - K J Meador
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, 213 Quarry Road, MC 5979, CA, 94304, USA
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22
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Effects of highly purified cannabidiol (CBD) on fMRI of working memory in treatment-resistant epilepsy. Epilepsy Behav 2020; 112:107358. [PMID: 32871501 DOI: 10.1016/j.yebeh.2020.107358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 01/08/2023]
Abstract
OBJECTIVE We aimed to determine changes in working memory and functional connectivity via functional magnetic resonance imaging (fMRI)-modified Sternberg task after treatment with highly purified cannabidiol (CBD, Epidiolex®; 100 mg/mL) in patients with treatment-resistant epilepsy (TRE). METHODS Twenty patients with TRE (mean age: 35.8 years; 7 male) performed fMRI Sternberg task before receiving CBD ("PRE") and after reaching stable dosage of CBD (15-25 mg/kg/day; "ON"). Each patient performed 2 runs of the modified Sternberg task during PRE and ON fMRI. Twenty-three healthy controls (HCs; mean age: 25 years; 11 M) also completed the task. All were presented with a sequence of 2 or 6 letters and instructed to remember them (encoding). After a delay, a single letter was shown, and participants recalled if letter was shown in sequence (retrieval). Paired t-tests were used to analyze accuracy/response times. For each subject, event-related modeling of encoding (2 and 6 letters) and retrieval was performed. Paired t-tests controlling for seizure frequency change and scanner type were performed to assess changes in neural recruitment during encoding and retrieval in key regions of interest. RESULTS There was nonsignificant increase in mean modified Sternberg task accuracy from PRE to ON-CBD (28.6 vs. 32.1%). PRE and ON accuracy was worse than HCs (75.5%, p < 0.001). ON-PRE comparison revealed increased activation in the right inferior frontal gyrus (IFG) during 6-letter encoding. ON-HC comparison revealed increased activation in bilateral IFG and insula during 2-letter encoding. PRE-HC comparison revealed decreased activation in the left middle frontal gyrus during 6-letter encoding. None of these activations were associated with working memory performance. SIGNIFICANCE Treatment-resistant epilepsy results in poorer working memory performance and lower neural recruitment compared with HCs. Treatment with CBD results in no significant changes in working memory performance and in significant increases in neural activity in regions important for verbal memory and attention compared with HCs during memory encoding.
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P2Y1 receptor inhibition rescues impaired synaptic plasticity and astroglial Ca 2+-dependent activity in the epileptic hippocampus. Neurobiol Dis 2020; 146:105132. [PMID: 33049315 DOI: 10.1016/j.nbd.2020.105132] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/15/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is characterized by a progressive predisposition to suffer seizures due to neuronal hyperexcitability, and one of its most common co-morbidities is cognitive decline. In animal models of chronic epilepsy, such as kindling, electrically induced seizures impair long-term potentiation (LTP), deteriorating learning and memory performance. Astrocytes are known to actively modulate synaptic plasticity and neuronal excitability through Ca2+-dependent gliotransmitter release. It is unclear, however, if astroglial Ca2+ signaling could contribute to the development of synaptic plasticity alterations in the epileptic hippocampus. By employing electrophysiological tools and Ca2+ imaging, we found that glutamatergic CA3-CA1 synapses from kindled rats exhibit an impairment in theta burst (TBS) and high frequency stimulation (HFS)-induced LTP, which is accompanied by an increased probability of neurotransmitter release (Pr) and an abnormal pattern of astroglial Ca2+-dependent transients. Both the impairment in LTP and the Pr were reversed by inhibiting purinergic P2Y1 receptors (P2Y1R) with the specific antagonist MRS2179, which also restored the spontaneous and TBS-induced pattern of astroglial Ca2+-dependent signals. Two consecutive, spaced TBS protocols also failed to induce LTP in the kindled group, however, this impairment was reversed and a strong LTP was induced when the second TBS was applied in the presence of MRS2179, suggesting that the mechanisms underlying the alterations in TBS-induced LTP are likely associated with an aberrant modulation of the induction threshold for LTP. Altogether, these results indicate that P2Y1R inhibition rescues both the pattern of astroglial Ca2+-activity and the plastic properties of CA3-CA1 synapses in the epileptic hippocampus, suggesting that astrocytes might take part in the mechanisms that deteriorate synaptic plasticity and thus cause cognitive decline in epileptic patients.
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Lourenço DM, Ribeiro-Rodrigues L, Sebastião AM, Diógenes MJ, Xapelli S. Neural Stem Cells and Cannabinoids in the Spotlight as Potential Therapy for Epilepsy. Int J Mol Sci 2020; 21:E7309. [PMID: 33022963 PMCID: PMC7582633 DOI: 10.3390/ijms21197309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/28/2020] [Accepted: 09/30/2020] [Indexed: 01/18/2023] Open
Abstract
Epilepsy is one of the most common brain diseases worldwide, having a huge burden in society. The main hallmark of epilepsy is the occurrence of spontaneous recurrent seizures, having a tremendous impact on the lives of the patients and of their relatives. Currently, the therapeutic strategies are mostly based on the use of antiepileptic drugs, and because several types of epilepsies are of unknown origin, a high percentage of patients are resistant to the available pharmacotherapy, continuing to experience seizures overtime. Therefore, the search for new drugs and therapeutic targets is highly important. One key aspect to be targeted is the aberrant adult hippocampal neurogenesis (AHN) derived from Neural Stem Cells (NSCs). Indeed, targeting seizure-induced AHN may reduce recurrent seizures and shed some light on the mechanisms of disease. The endocannabinoid system is a known modulator of AHN, and due to the known endogenous antiepileptic properties, it is an interesting candidate for the generation of new antiepileptic drugs. However, further studies and clinical trials are required to investigate the putative mechanisms by which cannabinoids can be used to treat epilepsy. In this manuscript, we will review how cannabinoid-induced modulation of NSCs may promote neural plasticity and whether these drugs can be used as putative antiepileptic treatment.
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Affiliation(s)
- Diogo M. Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Leonor Ribeiro-Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ana M. Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Maria J. Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; (D.M.L.); (L.R.-R.); (A.M.S.); (M.J.D.)
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
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Busch RM, Yehia L, Bazeley P, Seyfi M, Blümcke I, Hermann BP, Najm IM, Eng C. Verbal memory dysfunction is associated with alterations in brain transcriptome in dominant temporal lobe epilepsy. Epilepsia 2020; 61:2203-2213. [PMID: 32945555 DOI: 10.1111/epi.16673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/08/2020] [Accepted: 08/09/2020] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Memory dysfunction is prevalent in many neurological disorders and can have a significant negative impact on quality of life. The genetic contributions to memory impairment in epilepsy, particularly temporal lobe epilepsy (TLE), remain poorly understood. Here, we compare the brain transcriptome between TLE patients with and without verbal memory impairments to identify genes and signaling networks important for episodic memory. METHODS Brain tissues were resected from 23 adults who underwent dominant temporal lobectomy for treatment of pharmacoresistant epilepsy. To control for potential effects of APOE on memory, only those homozygous for the APOE ε3 allele were included. A battery of memory tests was performed, and patients were stratified into two groups based on preoperative memory performance. The groups were well matched on demographic and disease-related variables. Total RNA-Seq and small RNA-Seq were performed on RNA extracted from the brain tissues. Pathway and integrative analyses were subsequently performed. RESULTS We identified 1092 differentially expressed transcripts (DETs), with the majority (71%) being underexpressed in brain tissues from patients with impaired memory compared to those from patients with intact memory. Enrichment analysis revealed overrepresentation of genes in pathways pertaining to brain-related neurological dysfunction, including a subset associated with neurodegenerative diseases, memory, and cognition (APP, MAPT, PINK1). Despite including patients with identical APOE genotypes, we identify APOE as a differentially expressed gene associated with memory status. Small RNA-Seq identified four differentially expressed microRNAs (miRNAs) that were predicted to target a subset (22%) of all DETs. Integrative analysis showed that these miRNA-predicted DET targets impact brain-related pathways and biological processes also pertinent to memory and cognition. SIGNIFICANCE TLE-associated memory status may be influenced by differences in gene expression profiles within the temporal lobe. Upstream processes influencing differential expression signatures, such as miRNAs, could serve as biomarkers and potential treatment targets for memory impairment in TLE.
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Affiliation(s)
- Robyn M Busch
- Epilepsy Center and Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, Ohio.,Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Lamis Yehia
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Peter Bazeley
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Marilyn Seyfi
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Ingmar Blümcke
- Epilepsy Center and Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, Ohio.,Institute of Neuropathology, University Hospitals Erlangen, Erlangen, Germany
| | - Bruce P Hermann
- Department of Neurology, University of Wisconsin, Madison, Wisconsin
| | - Imad M Najm
- Epilepsy Center and Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, Ohio
| | - Charis Eng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.,Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio
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Samson S, Moncomble C, Méré M, Vasseur R, Dupont S. Getting older with chronic temporal lobe epilepsy: What memory profile? Rev Neurol (Paris) 2020; 176:439-443. [DOI: 10.1016/j.neurol.2020.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 10/24/2022]
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Neal EG, Di L, Reale-Caldwell A, Maciver S, Schoenberg MR, Vale FL. Network connectivity separate from the hypothesized irritative zone correlates with impaired cognition and higher rates of seizure recurrence. Epilepsy Behav 2019; 101:106585. [PMID: 31698262 DOI: 10.1016/j.yebeh.2019.106585] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/20/2019] [Accepted: 09/20/2019] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Surgery remains an essential option for the treatment of medically intractable temporal lobe epilepsy (TLE). However, only 66% of patients achieve postoperative seizure freedom, perhaps attributable to an incomplete understanding of brain network alterations in surgical candidates. Here, we applied a novel network modeling algorithm and measured key characteristics of epileptic networks correlated with surgical outcomes and objective measures of cognition. METHODS Twenty-two patients were prospectively included, and relevant demographic information was attained. Resting state functional magnetic resonance imaging (rsfMRI) and electroencephalography (EEG) data were recorded and preprocessed. Using our novel algorithm, patient-specific epileptic networks were mapped preoperatively, and geographic spread was quantified. Global functional connectivity was also determined using a volumetric functional atlas. Neuropsychological pre- and postsurgical raw and standardized scores obtained blinded to epileptic network status. Key demographic data and features of epileptic networks were then correlated with surgical outcome using Pearson's product-moment correlation. RESULTS At an average follow-up of 18.4 months, 15/22 (68%) patients were seizure-free. Connectivity was measured globally using a functional 3D atlas. Higher mean global connectivity correlated with worse scores in preoperative neuropsychological testing of executive functioning (Ruff Figural Fluency Test [RFFT]-ER; R = 0.943, p = 0.005). A higher ratio of highly correlated connections between regions of interest (ROIs) in the hemisphere contralateral to the seizure onset correlated with impairment in executive functioning (RFFT-ER; R = 0.943, p = 0.005). Higher numbers of highly correlated connections between ROIs in the contralateral hemisphere correlated with impairment in both short- and long-term measures of verbal memory (Rey Auditory Verbal Learning Test Trials 6, 7 [RAVLT6, RAVLT7]; R = -0.650, p = 0.020, R = -0.676, p = 0.030). Epilepsy networks were modeled in each patient, and localization of the epilepsy network in the bitemporal lobes correlated with lower scores in neuropsychological tests measuring verbal learning and short-term memory (RAVLT6; R = -0.671, p = 0.024). Higher rates of seizure recurrence correlated with localization of the epilepsy network bitemporally (R = -0.542, p = 0.014), with the stronger correlation found with localization to the contralateral temporal lobe from side of surgery (R = - 0.530, p = 0.016). CONCLUSION Increased connectivity contralateral to seizure onset and epilepsy network spread in the bitemporal lobes correlated with lower measures of executive functioning and verbal memory. Epilepsy network localization to the bitemporal lobes, in particular, the contralateral temporal lobe, is associated with higher rates of seizure recurrence. These findings may reflect network-level disruption that has infiltrated the contralateral hemisphere and the bitemporal lobes contributing to impaired cognition and relatively worse surgical outcomes. Further identification of network parameters that predict patient outcomes may aid in patient selection, resection planning, and ultimately the efficacy of epilepsy surgery.
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Affiliation(s)
- Elliot G Neal
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, USA
| | - Long Di
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, USA
| | - AmberRose Reale-Caldwell
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, USA; Department of Neurology, University of South Florida, Tampa, FL, USA
| | - Stephanie Maciver
- Department of Neurology, University of South Florida, Tampa, FL, USA
| | - Mike R Schoenberg
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, USA; Department of Neurology, University of South Florida, Tampa, FL, USA
| | - Fernando L Vale
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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Marchionni I, Oberoi M, Soltesz I, Alexander A. Ripple-related firing of identified deep CA1 pyramidal cells in chronic temporal lobe epilepsy in mice. Epilepsia Open 2019; 4:254-263. [PMID: 31168492 PMCID: PMC6546014 DOI: 10.1002/epi4.12310] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/02/2019] [Accepted: 01/19/2019] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) is often associated with memory deficits. Reactivation of memory traces in the hippocampus occurs during sharp-wave ripples (SWRs; 140-250 Hz). To better understand the mechanisms underlying high-frequency oscillations and cognitive comorbidities in epilepsy, we evaluated how rigorously identified deep CA1 pyramidal cells (dPCs) discharge during SWRs in control and TLE mice. METHODS We used the unilateral intraamygdala kainate model of TLE in video-electroencephalography (EEG) verified chronically epileptic adult mice. Local field potential and single-cell recordings were performed using juxtacellular recordings from awake control and TLE mice resting on a spherical treadmill, followed by post hoc identification of the recorded cells. RESULTS Hippocampal SWRs in TLE mice occurred with increased intraripple frequency compared to control mice. The frequency of SWR events was decreased, whereas the overall frequency of SWRs, interictal epileptiform discharges, and high-frequency ripples (250-500 Hz) together was not altered. CA1 dPCs in TLE mice showed significantly increased firing during ripples as well as between the ripple events. The strength of ripple modulation of dPC discharges increased in TLE without alteration of the preferred phase of firing during the ripple waves. SIGNIFICANCE These juxtacellular electrophysiology data obtained from identified CA1 dPCs from chronically epileptic mice are in general agreement with recent findings indicating distortion of normal firing patterns during offline SWRs as a mechanism underlying deficits in memory consolidation in epilepsy. Because the primary seizure focus in our experiments was in the amygdala and we recorded from the CA1 region, these results are also in agreement with the presence of altered high-frequency oscillations in areas of secondary seizure spread.
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Affiliation(s)
- Ivan Marchionni
- Department of Anatomy & NeurobiologyUniversity of CaliforniaIrvineCalifornia
- Department of Biomedical Sciences and Padova Neuroscience CenterUniversity of PadovaPadovaItaly
| | - Michelle Oberoi
- Department of Anatomy & NeurobiologyUniversity of CaliforniaIrvineCalifornia
- University of CaliforniaRiverside School of MedicineRiversideCalifornia
| | - Ivan Soltesz
- Department of Anatomy & NeurobiologyUniversity of CaliforniaIrvineCalifornia
- Department of NeurosurgeryStanford UniversityStanfordCalifornia
| | - Allyson Alexander
- Department of NeurosurgeryAnschutz School of MedicineUniversity of Colorado DenverAuroraColorado
- Department of NeurosurgeryChildren's Hospital ColoradoAuroraColorado
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Baraban SC. Viral tracing of presynaptic inputs to newly born dentate granule cells in a rodent model of mesial temporal lobe epilepsy. Ann Neurol 2019; 81:769-771. [PMID: 28470692 DOI: 10.1002/ana.24945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 04/17/2017] [Accepted: 04/26/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Scott C Baraban
- Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco San Francisco, CA
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Kundap UP, Paudel YN, Kumari Y, Othman I, Shaikh MF. Embelin Prevents Seizure and Associated Cognitive Impairments in a Pentylenetetrazole-Induced Kindling Zebrafish Model. Front Pharmacol 2019; 10:315. [PMID: 31057394 PMCID: PMC6478791 DOI: 10.3389/fphar.2019.00315] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/14/2019] [Indexed: 01/10/2023] Open
Abstract
Epilepsy is a neuronal disorder associated with several neurological and behavioral alterations characterized by recurrent spontaneous epileptic seizures. Despite having more than 20 anti-epileptic drugs (AEDs), they only provide a symptomatic treatment. As well as, currently available AEDs also displayed cognitive alterations in addition to retarding seizure. This leads to the need for exploring new molecules that not only retard seizure but also improve cognitive impairment. Embelin (EMB) is a benzoquinone derivative which has already demonstrated its pharmacological potentials against arrays of neurological conditions. The current study developed a chronic kindling model in adult zebrafish by using repeated administration of small doses of pentylenetetrazole (PTZ) and a single dose of Kainic acid (KA) to investigate the associated memory impairment. This has been done by using the three-axis maze which is a conventional method to test the learning ability and egocentric memory in zebrafish. As well as, the ameliorative potential of EMB has been evaluated against chronic epilepsy-related memory alterations. Moreover the expression level of pro-inflammatory genes such as C-C motif ligand 2 (CCL2), toll-like receptor-4 (TLR4), tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1) and interferon-γ (IFN-γ) were evaluated. The level of several neurotransmitters such as γ-aminobutyric acid (GABA), acetylcholine (Ach) and glutamate (Glu) was evaluated by liquid chromatography-mass spectrometry (LC-MS). The results showed that daily dose of PTZ 80 mg/kg for 10 days successfully induces a kindling effect in zebrafish, whereas the single dose of KA did not. As compared to control, the PTZ and KA group demonstrates impairment in memory as demonstrated by the three-axis maze. The PTZ group treated with a series of EMB doses (ranging from 0.156 to 0.625 mg/kg) was found to have retarded seizure as well as significantly reduces epilepsy-induced memory alteration. In addition, EMB treatment reduces the expression of inflammatory markers implicating its anti-inflammatory potential. Moreover, levels of GABA, Ach, and glutamate are increased in EMB administered group as compared to the PTZ administered group. Overall, findings demonstrate that EMB might be a potential candidate against chronic epilepsy-related cognitive dysfunction as EMB prevents the seizures, so we expect it to prevent the associated neuroinflammation and learning deficit.
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Affiliation(s)
- Uday Praful Kundap
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia.,University of Montreal Hospital Centre (CRCHUM), Montreal, QC, Canada
| | - Yam Nath Paudel
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Yatinesh Kumari
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Iekshan Othman
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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Very long-term outcome in resected and non-resected patients with temporal lobe epilepsy with medial temporal lobe sclerosis: A multiple case-study. Seizure 2019; 67:30-37. [DOI: 10.1016/j.seizure.2019.02.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 11/20/2022] Open
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Vrinda M, Arun S, Srikumar B, Kutty BM, Shankaranarayana Rao B. Temporal lobe epilepsy-induced neurodegeneration and cognitive deficits: Implications for aging. J Chem Neuroanat 2019; 95:146-153. [DOI: 10.1016/j.jchemneu.2018.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 02/16/2018] [Accepted: 02/16/2018] [Indexed: 12/12/2022]
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Helmstaedter C, Winter B, Melzer N, Lohmann H, Witt JA. Accelerated long-term forgetting in focal epilepsies with special consideration given to patients with diagnosed and suspected limbic encephalitis. Cortex 2019; 110:58-68. [DOI: 10.1016/j.cortex.2018.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 07/13/2017] [Accepted: 01/05/2018] [Indexed: 02/04/2023]
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Celiker Uslu S, Yuksel B, Tekin B, Sariahmetoglu H, Atakli D. Cognitive impairment and drug responsiveness in mesial temporal lobe epilepsy. Epilepsy Behav 2019; 90:162-167. [PMID: 30576963 DOI: 10.1016/j.yebeh.2018.10.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/17/2018] [Accepted: 10/24/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Mesial temporal lobe epilepsy (MTLE) is the most common form of partial epilepsies. Seizures of MTLE with hippocampal sclerosis (MTLE-HS) are typically resistant to antiepileptic drug (AED) therapy. Although memory disturbances in patients with MTLE-HS are expected, verbal attention and frontal lobe functions may also be impaired. We aimed to examine the relationship between the clinical features and cognitive functions of patients by comparing cognitive test scores of patients with MTLE with few seizures (drug-responsive group) and those with frequent seizures (pharmacoresistant group). METHODS Seventy-nine patients with MTLE-HS and 30 healthy controls were enrolled. Thirty-four patients were accepted as the drug-responsive group (DrG), and 45 patients were included in the pharmacoresistant group (PRG). Tests evaluating attention, memory, and executive functions were performed on all participants. RESULTS Forty-nine (62%) female and 30 (38%) male patients with MTLE-HS, and 14 (46.7%) female and 16 (53.3%) male controls participated in the study. The mean age of the patients and controls was 33.53 ± 9.60 (range, 18-57) years and 35.90 ± 7.98 (range, 18-56) years, respectively. Both the DrG and PRG showed poorer performances in tests evaluating memory and frontal lobe functions when compared with the control group (CG). Additionally, attention test results were significantly worse in the PRG than in the DrG. CONCLUSION It is reasonable to say that increased seizure frequency is the main causative factor of verbal attention deficit due to the poorer attention test results in the PRG. Poor performances in memory and frontal lobe function tests of all patients with MTLE-HS emphasized the importance of the mutual connection between the temporal lobe and prefrontal cortices.
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Affiliation(s)
- Sibel Celiker Uslu
- Samsun Training and Research Hospital Neurology Department, İlkadım, 55090 Samsun, Turkey
| | - Burcu Yuksel
- Antalya Training and Research Hospital, Neurology Department, Muratpasa, 07050 Antalya, Turkey.
| | - Betul Tekin
- Rumeli Hospital Neurology Department, Kucukcekmece, 34295 Istanbul, Turkey
| | - Hande Sariahmetoglu
- Bakirkoy Training and Research Hospital for Psychiatry, Neurology and Neurosurgery, Neurology Department, Bakirkoy, 34147 Istanbul, Turkey
| | - Dilek Atakli
- Bakirkoy Training and Research Hospital for Psychiatry, Neurology and Neurosurgery, Neurology Department, Bakirkoy, 34147 Istanbul, Turkey
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Izadi A, Ondek K, Schedlbauer A, Keselman I, Shahlaie K, Gurkoff G. Clinically indicated electrical stimulation strategies to treat patients with medically refractory epilepsy. Epilepsia Open 2018; 3:198-209. [PMID: 30564779 PMCID: PMC6293066 DOI: 10.1002/epi4.12276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2018] [Indexed: 12/25/2022] Open
Abstract
Focal epilepsies represent approximately half of all diagnoses, and more than one-third of these patients are refractory to pharmacologic treatment. Although resection can result in seizure freedom, many patients do not meet surgical criteria, as seizures may be multifocal in origin or have a focus in an eloquent region of the brain. For these individuals, several U.S. Food and Drug Administration (FDA)-approved electrical stimulation paradigms serve as alternative options, including vagus nerve stimulation, responsive neurostimulation, and stimulation of the anterior nucleus of the thalamus. All of these are safe, flexible, and lead to progressive seizure control over time when used as an adjunctive therapy to antiepileptic drugs. Focal epilepsies frequently involve significant comorbidities such as cognitive decline. Similar to antiepilepsy medications and surgical resection, current stimulation targets and parameters have yet to address cognitive impairments directly, with patients reporting persistent comorbidities associated with focal epilepsy despite a significant reduction in the number of their seizures. Although low-frequency theta oscillations of the septohippocampal network are critical for modulating cellular activity and, in turn, cognitive processing, the coordination of neural excitability is also imperative for preventing seizures. In this review, we summarize current FDA-approved electrical stimulation paradigms and propose that theta oscillations of the medial septal nucleus represent a novel neuromodulation target for concurrent seizure reduction and cognitive improvement in epilepsy. Ultimately, further advancements in clinical neurostimulation strategies will allow for the efficient treatment of both seizures and comorbidities, thereby improving overall quality of life for patients with epilepsy.
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Affiliation(s)
- Ali Izadi
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Katelynn Ondek
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Center for NeuroscienceUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Amber Schedlbauer
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Inna Keselman
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Department of NeurologyUniversity of CaliforniaDavisCaliforniaU.S.A.
| | - Kiarash Shahlaie
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Center for NeuroscienceUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Gene Gurkoff
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Center for NeuroscienceUniversity of CaliforniaDavisCalifornia,U.S.A.
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Lee JM, Ji ES, Kim TW, Kim CJ, Shin MS, Lim BV, Chung YR, Cho YS. Treadmill exercise improves memory function by inhibiting hippocampal apoptosis in pilocarpine-induced epileptic rats. J Exerc Rehabil 2018; 14:713-723. [PMID: 30443515 PMCID: PMC6222143 DOI: 10.12965/jer.36394.197] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 09/05/2018] [Indexed: 12/05/2022] Open
Abstract
Epilepsy is characterized by recurrent seizures and loss of neurons with abnormal rhythmic firing in the brains. In the present study, we investigated the effect of treadmill exercise on memory function in relation with cell proliferation and apoptosis in the hippocampus using pilocarpine-induced seizure rats. Epilepsy was initiated by intraperitoneal injection of pilocarpine hydrochloride. The rats in the exercise group were forced to run on a motorized treadmill for 30 min once a day for 2 weeks. In the present results, treadmill exercise alleviated short-term and spatial learning memory impairments in the epileptic rats. Treadmill exercise suppressed neuronal degeneration and enhanced neuronal maturation in the epileptic rats. Treadmill exercise suppressed cell proliferation and apoptosis in the epileptic rats. Treadmill exercise alleviated pilocarpine-induced memory impairments and suppressed neuronal loss in the hippocampus through down-regulation of apoptosis. These findings offer a possibility that treadmill exercise may provide a preventive or therapeutic value to the epilepsy-induced learning and memory impairments.
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Affiliation(s)
- Jae-Min Lee
- Department of Pharmacology, School of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Eun-Sang Ji
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Tae-Woon Kim
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Chang-Ju Kim
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Mal-Soon Shin
- School of Global Sport Studies, Korea University, Sejong, Korea
| | - Baek-Vin Lim
- Division of Leisure & Sports Science, Department of Exercise Prescription, Dongseo University, Busan, Korea
| | - Yong-Rak Chung
- Department of Golf Mapping, College of Arts Physical Education, Joongbu University, Geumsan, Korea
| | - Young Sam Cho
- Department of Urology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
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Kitchigina VF. Alterations of Coherent Theta and Gamma Network Oscillations as an Early Biomarker of Temporal Lobe Epilepsy and Alzheimer's Disease. Front Integr Neurosci 2018; 12:36. [PMID: 30210311 PMCID: PMC6119809 DOI: 10.3389/fnint.2018.00036] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 07/30/2018] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) and temporal lobe epilepsy (TLE) are the most common forms of neurodegenerative disorders characterized by the loss of cells and progressive irreversible alteration of cognitive functions, such as attention and memory. AD may be an important cause of epilepsy in the elderly. Early diagnosis of diseases is very important for their successful treatment. Many efforts have been done for defining new biomarkers of these diseases. Significant advances have been made in the searching of some AD and TLE reliable biomarkers, including cerebrospinal fluid and plasma measurements and glucose positron emission tomography. However, there is a great need for the biomarkers that would reflect changes of brain activity within few milliseconds to obtain information about cognitive disturbances. Successful early detection of AD and TLE requires specific biomarkers capable of distinguishing individuals with the progressing disease from ones with other pathologies that affect cognition. In this article, we review recent evidence suggesting that magnetoencephalographic recordings and coherent analysis coupled with behavioral evaluation can be a promising approach to an early detection of AD and TLE. Highlights -Data reviewed include the results of clinical and experimental studies.-Theta and gamma rhythms are disturbed in epilepsy and AD.-Common and different behavioral and oscillatory features of pathologies are compared.-Coherent analysis can be useful for an early diagnostics of diseases.
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Affiliation(s)
- Valentina F Kitchigina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences (RAS), Pushchino, Russia
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Gao Y, Zheng J, Li Y, Guo D, Wang M, Cui X, Ye W. Decreased functional connectivity and structural deficit in alertness network with right-sided temporal lobe epilepsy. Medicine (Baltimore) 2018; 97:e0134. [PMID: 29620625 PMCID: PMC5902293 DOI: 10.1097/md.0000000000010134] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Patients with temporal lobe epilepsy (TLE) often suffer from alertness alterations. However, specific regions connected with alertness remain controversial, and whether these regions have structural impairment is also elusive. This study aimed to investigate the characteristics and neural mechanisms underlying the functions and structures of alertness network in patients with right-sided temporal lobe epilepsy (rTLE) by performing the attentional network test (ANT), resting-state functional magnetic resonance imaging (R-SfMRI), and diffusion tensor imaging (DTI).A total of 47 patients with rTLE and 34 healthy controls underwent ANT, R-SfMRI, and DTI scan. The seed-based functional connectivity (FC) method and deterministic tractography were used to analyze the data.Patients with rTLE had longer reaction times in the no-cue and double-cue conditions. However, no differences were noted in the alertness effect between the 2 groups. The patient group had lower FC compared with the control group in the right inferior parietal lobe (IPL), amygdala, and insula. Structural deficits were found in the right parahippocampal gyrus, superior temporal pole, insula, and amygdala in the patient group compared with the control group. Also significantly negative correlations were observed between abnormal fractional anisotropy (between the right insula and the superior temporal pole) and illness duration in the patients with rTLE.The findings of this study suggested abnormal intrinsic and phasic alertness, decreased FC, and structural deficits within the alerting network in the rTLE. This study provided new insights into the mechanisms of alertness alterations in rTLE.
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Affiliation(s)
| | | | | | | | | | | | - Wei Ye
- Department of Radiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
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Verbal and Figural Fluency in Temporal Lobe Epilepsy: Does Hippocampal Sclerosis Affect Performance? Cogn Behav Neurol 2017. [PMID: 28632521 DOI: 10.1097/wnn.0000000000000123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES Clinicians commonly use verbal and nonverbal measures to test fluency in patients with epilepsy, either during routine cognitive assessment or as part of pre- and postsurgical evaluation. We hypothesized that patients with mesial temporal lobe epilepsy (TLE) with hippocampal sclerosis would perform worse than patients with lateral TLE in both verbal and design fluency. METHODS We assessed semantic, phonemic, and nonverbal fluency in 49 patients with TLE: 31 with lateral TLE and 18 with mesial TLE plus hippocampal sclerosis. We also gave non-fluency cognitive measures: psychomotor speed, attentional set shifting, selective attention, abstract reasoning, verbal and visual episodic memory, and incidental memory. RESULTS Patients with mesial TLE performed significantly worse on figural fluency than patients with lateral TLE. Even though group differences on verbal fluency measures were not significant, the patients with mesial TLE had a pattern of poorer performance. The patients with mesial TLE scored significantly worse on measures of selective attention, verbal episodic memory, and incidental memory. CONCLUSIONS Our study underlines differences in cognitive function between patients with mesial and lateral TLE, particularly in figural fluency. Although we cannot directly assess the role of the hippocampus in cognitive aspects of creative and divergent thinking related to figural fluency, the cognitive discrepancies between these two TLE groups could be ascribed to the mesial TLE hippocampal pathology shown in our study and addressed in the literature on hippocampal involvement in divergent thinking. Our findings could benefit cognitive rehabilitation programs tailored to the needs of patients with TLE.
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Kamenskiy IS, Kaymovskiy IL, Gersamiya AG, Vavilina IS. [Cognitive impairment. The effects of seizures?]. Zh Nevrol Psikhiatr Im S S Korsakova 2017; 117:50-54. [PMID: 29213039 DOI: 10.17116/jnevro20171179250-54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This review discusses articles on cognitive impairments developing after one or more convulsive seizures. Cognitive disorders seem to be frequent complications of epilepsy. According to recent clinical studies, the intensity of cognitive declines depends on a frequency and severity of seizures. However, presence of an epileptic focus does not always indicate an increase in cognitive impairments. An effect of a single convulsive seizure on cognitive functions at this stage is uncertain. According to some data, cognitive impairments after a single generalized seizures develop only in specific clinical syndromes, on the other hand, they are influenced by the emotional state of the subject. This problem remains relevant today. Further work is needed in this direction.
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Affiliation(s)
| | | | - A G Gersamiya
- Moscow Research and Clinical Center for Neuropsychiatry, Moscow, Russia
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Unraveling the Role of the Hippocampus in Reversal Learning. J Neurosci 2017; 37:6686-6697. [PMID: 28592695 DOI: 10.1523/jneurosci.3212-16.2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 04/25/2017] [Accepted: 05/14/2017] [Indexed: 11/21/2022] Open
Abstract
Research in reversal learning has mainly focused on the functional role of dopamine and striatal structures in driving behavior on the basis of classic reinforcement learning mechanisms. However, recent evidence indicates that, beyond classic reinforcement learning adaptations, individuals may also learn the inherent task structure and anticipate the occurrence of reversals. A candidate structure to support such task representation is the hippocampus, which might create a flexible representation of the environment that can be adaptively applied to goal-directed behavior. To investigate the functional role of the hippocampus in the implementation of anticipatory strategies in reversal learning, we first studied, in 20 healthy individuals (11 women), whether the gray matter anatomy and volume of the hippocampus were related to anticipatory strategies in a reversal learning task. Second, we tested 20 refractory temporal lobe epileptic patients (11 women) with unilateral hippocampal sclerosis, who served as a hippocampal lesion model. Our results indicate that healthy participants were able to learn the task structure and use it to guide their behavior and optimize their performance. Participants' ability to adopt anticipatory strategies correlated with the gray matter volume of the hippocampus. In contrast, hippocampal patients were unable to grasp the higher-order structure of the task with the same success than controls. Present results indicate that the hippocampus is necessary to respond in an appropriately flexible manner to high-order environments, and disruptions in this structure can render behavior habitual and inflexible.SIGNIFICANCE STATEMENT Understanding the neural substrates involved in reversal learning has provoked a great deal of interest in the last years. Studies with nonhuman primates have shown that, through repetition, individuals are able to anticipate the occurrence of reversals and, thus, adjust their behavior accordingly. The present investigation is devoted to know the role of the hippocampus in such strategies. Importantly, our findings evidence that the hippocampus is necessary to anticipate the occurrence of reversals, and disruptions in this structure can render behavior habitual and inflexible.
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Abstract
Memory difficulties are commonly associated with temporal lobe epilepsy (TLE) and cause significant disability. This article reviews the role of altered hippocampal theta oscillations and theta-gamma coupling as potential causes of memory disturbance in temporal lobe epilepsy, dissecting the potential mechanisms underlying these changes in large-scale neuronal synchronization. We discuss development of treatments for cognitive dysfunction directed at restoring theta rhythmicity and future directions for research.
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Klamer S, Milian M, Erb M, Rona S, Lerche H, Ethofer T. Face-name association task reveals memory networks in patients with left and right hippocampal sclerosis. NEUROIMAGE-CLINICAL 2017; 14:174-182. [PMID: 28180076 PMCID: PMC5279692 DOI: 10.1016/j.nicl.2017.01.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 01/17/2017] [Accepted: 01/20/2017] [Indexed: 11/23/2022]
Abstract
We aimed to identify reorganization processes of episodic memory networks in patients with left and right temporal lobe epilepsy (TLE) due to hippocampal sclerosis as well as their relations to neuropsychological memory performance. We investigated 28 healthy subjects, 12 patients with left TLE (LTLE) and 9 patients with right TLE (RTLE) with hippocampal sclerosis by means of functional magnetic resonance imaging (fMRI) using a face-name association task, which combines verbal and non-verbal memory functions. Regions-of-interest (ROIs) were defined based on the group results of the healthy subjects. In each ROI, fMRI activations were compared across groups and correlated with verbal and non-verbal memory scores. The face-name association task yielded activations in bilateral hippocampus (HC), left inferior frontal gyrus (IFG), left superior frontal gyrus (SFG), left superior temporal gyrus, bilateral angular gyrus (AG), bilateral medial prefrontal cortex and right anterior temporal lobe (ATL). LTLE patients demonstrated significantly less activation in the left HC and left SFG, whereas RTLE patients showed significantly less activation in the HC bilaterally, the left SFG and right AG. Verbal memory scores correlated with activations in the left and right HC, left SFG and right ATL and non-verbal memory scores with fMRI activations in the left and right HC and left SFG. The face-name association task can be employed to examine functional alterations of hippocampal activation during encoding of both verbal and non-verbal material in one fMRI paradigm. Further, the left SFG seems to be a convergence region for encoding of verbal and non-verbal material. Memory networks in patients with hippocampal sclerosis were compared to controls. Verbal and nonverbal memory correlated with activations in both HC and left SFG Patients with left hippocampal sclerosis activated less in the left HC and left SFG. Patients with right-sided lesion activated less in both HC, left SFG and right AG. Left SFG seems to be convergence region for encoding of verbal + nonverbal material.
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Affiliation(s)
- Silke Klamer
- Department of Neurology and Epileptology, University Hospital Tübingen and Hertie Institute of Clinical Brain Research, Tübingen, Germany
| | - Monika Milian
- Department of Neurosurgery, University Hospital Tübingen, Tübingen, Germany
| | - Michael Erb
- Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
| | - Sabine Rona
- Department of Neurosurgery, University Hospital Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, University Hospital Tübingen and Hertie Institute of Clinical Brain Research, Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas Ethofer
- Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany; Department of Psychiatry and Psychotherapy, University Hospital Tübingen, Tübingen, Germany
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Abstract
SummaryIntroduction.Medial temporal lobe epilepsy (MTLE) is the most frequent form of epilepsy in adulthood. It is classified as local/regional epilepsy. However, there is increasing evidence of the involvement of both temporal lobes and this provides abundant arguments to question this view, and consider MTLE as one of the typical bilateral system epilepsies.Aim.To provide a contemporary review of medial temporal lobe epilepsy, discussing the bilateral aspects, with reference to epilepsy surgery.Methods.A literature review and a resume of the author’s own experiences with MTLE patients.Results.Recent electrophysiological and neuroimaging data provide convincing data supporting that MTLE is a bilateral disease. The uni-and bilateral features form a continuum and the participation rate of the two temporal lobes determine course and surgical perspective of the individual patient.Conclusions.The contradictory data of invasive presurgical evaluations of MTLE patients suggest that there need to identify further indicatory markers of bilaterality and thus change the presurgical evaluation from the non-invasive towards the invasive ways. The mechanisms of the interrelationship between the two temporal lobes in MTLE warrants further research.
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45
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Altered Oscillatory Dynamics of CA1 Parvalbumin Basket Cells during Theta-Gamma Rhythmopathies of Temporal Lobe Epilepsy. eNeuro 2016; 3:eN-NWR-0284-16. [PMID: 27896315 PMCID: PMC5114702 DOI: 10.1523/eneuro.0284-16.2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/25/2016] [Accepted: 10/25/2016] [Indexed: 12/23/2022] Open
Abstract
Recent reports in human demonstrate a role of theta–gamma coupling in memory for spatial episodes and a lack of coupling in people experiencing temporal lobe epilepsy, but the mechanisms are unknown. Using multisite silicon probe recordings of epileptic rats engaged in episodic-like object recognition tasks, we sought to evaluate the role of theta–gamma coupling in the absence of epileptiform activities. Our data reveal a specific association between theta–gamma (30–60 Hz) coupling at the proximal stratum radiatum of CA1 and spatial memory deficits. We targeted the microcircuit mechanisms with a novel approach to identify putative interneuronal types in tetrode recordings (parvalbumin basket cells in particular) and validated classification criteria in the epileptic context with neurochemical identification of intracellularly recorded cells. In epileptic rats, putative parvalbumin basket cells fired poorly modulated at the falling theta phase, consistent with weaker inputs from Schaffer collaterals and attenuated gamma oscillations, as evaluated by theta-phase decomposition of current–source density signals. We propose that theta–gamma interneuronal rhythmopathies of the temporal lobe are intimately related to episodic memory dysfunction in this condition.
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Bungenberg J, Surano N, Grote A, Surges R, Pernhorst K, Hofmann A, Schoch S, Helmstaedter C, Becker AJ. Gene expression variance in hippocampal tissue of temporal lobe epilepsy patients corresponds to differential memory performance. Neurobiol Dis 2015; 86:121-30. [PMID: 26631617 DOI: 10.1016/j.nbd.2015.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/27/2015] [Accepted: 11/13/2015] [Indexed: 01/05/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is a severe brain disorder affecting particularly young adults. TLE is frequently associated with memory deterioration and neuronal damage of the hippocampal formation. It thereby reveals striking parallels to neurodegenerative disorders including Alzheimer's disease (AD). TLE patients differ with respect to their cognitive performance, but currently little is known about relevant molecular-genetic factors. Here, we correlated differential memory performance of pharmacoresistant TLE patients undergoing neurosurgery for seizure control with in-vitro findings of their hippocampal tissues. We analyzed mRNA transcripts and subsequently promoter variants specifically altered in brain tissue of individuals with 'very severe' memory impairment. TLE patients (n=79) were stratified according to preoperative memory impairment using an established four-tiered grading system ranging from 'average' to 'very severely'. Multimodal cluster analyses revealed molecules specifically associated with synaptic function and abundantly expressed in TLE patients with very impaired memory performance. In a subsequent promoter analysis, we found the single nucleotide polymorphism rs744373 C-allele to be associated with high mRNA levels of bridging integrator 1 (BIN1)/Amphiphysin 2, i.e. a major component of the endocytotic machinery and located in a crucial genetic AD risk locus. Using in vitro luciferase transfection assays, we found that BIN1 promoter activation is genotype dependent and strongly increased by reduced binding of the transcriptional repressor TGIF. Our data indicate that poor memory performance in patients with TLE strongly corresponds to distinctly altered neuronal transcript signatures, which - as demonstrated for BIN1 - can correlate with a particular allelic promoter variant. Our data suggest aberrant transcriptional signaling to significantly impact synaptic dynamics in TLE resulting in impaired memory performance and may serve as basis for future therapy development of this severe comorbidity.
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Affiliation(s)
- Julia Bungenberg
- Dept. of Neuropathology, University of Bonn Medical Center, Germany
| | - Natascha Surano
- Dept. of Neuropathology, University of Bonn Medical Center, Germany
| | - Alexander Grote
- Dept. of Neurosurgery, University of Bonn Medical Center, Germany
| | - Rainer Surges
- Dept. of Epileptology, University of Bonn Medical Center, Germany
| | | | - Andrea Hofmann
- Institute of Human Genetics, Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany
| | - Susanne Schoch
- Dept. of Neuropathology, University of Bonn Medical Center, Germany
| | | | - Albert J Becker
- Dept. of Neuropathology, University of Bonn Medical Center, Germany.
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Abstract
Seizure activity in the hippocampal region strongly affects stem cell-associated plasticity in the adult dentate gyrus. Here, we describe how seizures in rodent models of mesial temporal lobe epilepsy (mTLE) affect multiple steps in the developmental course from the dividing neural stem cell to the migrating and integrating newborn neuron. Furthermore, we discuss recent evidence indicating either that seizure-induced aberrant neurogenesis may contribute to the epileptic disease process or that altered neurogenesis after seizures may represent an attempt of the injured brain to repair itself. Last, we describe how dysfunction of adult neurogenesis caused by chronic seizures may play an important role in the cognitive comorbidities associated with mTLE.
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Affiliation(s)
| | - Jack M Parent
- Department of Neurology, University of Michigan Medical Center and VA Ann Arbor Healthcare System, Ann Arbor, Michigan 48109
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48
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Kaur H, Patro I, Tikoo K, Sandhir R. Curcumin attenuates inflammatory response and cognitive deficits in experimental model of chronic epilepsy. Neurochem Int 2015; 89:40-50. [DOI: 10.1016/j.neuint.2015.07.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 07/12/2015] [Accepted: 07/14/2015] [Indexed: 12/20/2022]
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Semantic Processing Impairment in Patients with Temporal Lobe Epilepsy. EPILEPSY RESEARCH AND TREATMENT 2015; 2015:746745. [PMID: 26257956 PMCID: PMC4519536 DOI: 10.1155/2015/746745] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/02/2015] [Indexed: 11/17/2022]
Abstract
The impairment in episodic memory system is the best-known cognitive deficit in patients with temporal lobe epilepsy (TLE). Recent studies have shown evidence of semantic disorders, but they have been less studied than episodic memory. The semantic dysfunction in TLE has various cognitive manifestations, such as the presence of language disorders characterized by defects in naming, verbal fluency, or remote semantic information retrieval, which affects the ability of patients to interact with their surroundings. This paper is a review of recent research about the consequences of TLE on semantic processing, considering neuropsychological, electrophysiological, and neuroimaging findings, as well as the functional role of the hippocampus in semantic processing. The evidence from these studies shows disturbance of semantic memory in patients with TLE and supports the theory of declarative memory of the hippocampus. Functional neuroimaging studies show an inefficient compensatory functional reorganization of semantic networks and electrophysiological studies show a lack of N400 effect that could indicate that the deficit in semantic processing in patients with TLE could be due to a failure in the mechanisms of automatic access to lexicon.
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50
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Abstract
Coherent neuronal activity in the hippocampal-entorhinal circuit is a critical mechanism for episodic memory function, which is typically impaired in temporal lobe epilepsy. To better understand how this mechanism is implemented and degraded in this condition, we used normal and epileptic rats to examine theta activity accompanying active exploration. Assisted by multisite recordings of local field potentials (LFPs) and layer-specific profiling of input pathways, we provide detailed quantification of the proximodistal coherence of theta activity in the dorsal hippocampus of these animals. Normal rats showed stronger coordination between the temporoammonic and perforant entorhinal inputs (measured from lamina-specific current source density signals) at proximal locations, i.e., closer to CA3; while epileptic rats exhibited stronger interactions at distal locations, i.e., closer to subiculum. This opposing trend in epileptic rats was associated with the reorganization of the temporoammonic and perforant pathways that accompany hippocampal sclerosis, the pathological hallmark of this disease. In addition to this connectivity constraint, we discovered that the appropriate timing between entorhinal inputs arriving over several theta cycles at the proximal and distal ends of the dorsal hippocampus was impaired in epileptic rats. Computational reconstruction of LFP signals predicted that restoring timing variability has a major impact on repairing theta coherence. This manipulation, when tested pharmacologically via systemic administration of group III mGluR antagonists, successfully re-established theta coordination of LFPs in epileptic rats. Thus, proximodistal organization of entorhinal inputs is instrumental in temporal lobe physiology and a candidate mechanism to study cognitive comorbidities of temporal lobe epilepsy.
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