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Kandratavicius L, Balista PA, Lopes-Aguiar C, Ruggiero RN, Umeoka EH, Garcia-Cairasco N, Bueno-Junior LS, Leite JP. Animal models of epilepsy: use and limitations. Neuropsychiatr Dis Treat 2014; 10:1693-705. [PMID: 25228809 PMCID: PMC4164293 DOI: 10.2147/ndt.s50371] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Epilepsy is a chronic neurological condition characterized by recurrent seizures that affects millions of people worldwide. Comprehension of the complex mechanisms underlying epileptogenesis and seizure generation in temporal lobe epilepsy and other forms of epilepsy cannot be fully acquired in clinical studies with humans. As a result, the use of appropriate animal models is essential. Some of these models replicate the natural history of symptomatic focal epilepsy with an initial epileptogenic insult, which is followed by an apparent latent period and by a subsequent period of chronic spontaneous seizures. Seizures are a combination of electrical and behavioral events that are able to induce chemical, molecular, and anatomic alterations. In this review, we summarize the most frequently used models of chronic epilepsy and models of acute seizures induced by chemoconvulsants, traumatic brain injury, and electrical or sound stimuli. Genetic models of absence seizures and models of seizures and status epilepticus in the immature brain were also examined. Major uses and limitations were highlighted, and neuropathological, behavioral, and neurophysiological similarities and differences between the model and the human equivalent were considered. The quest for seizure mechanisms can provide insights into overall brain functions and consciousness, and animal models of epilepsy will continue to promote the progress of both epilepsy and neurophysiology research.
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Affiliation(s)
- Ludmyla Kandratavicius
- Department of Neurosciences and Behavior, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Priscila Alves Balista
- Department of Neurosciences and Behavior, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Cleiton Lopes-Aguiar
- Department of Neurosciences and Behavior, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Rafael Naime Ruggiero
- Department of Neurosciences and Behavior, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Eduardo Henrique Umeoka
- Department of Physiology, Ribeirao Preto School of Medicine, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Norberto Garcia-Cairasco
- Department of Physiology, Ribeirao Preto School of Medicine, University of Sao Paulo, Ribeirao Preto, Brazil
| | | | - Joao Pereira Leite
- Department of Neurosciences and Behavior, University of Sao Paulo, Ribeirao Preto, Brazil
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Witt JA, Coras R, Schramm J, Becker AJ, Elger CE, Blümcke I, Helmstaedter C. The overall pathological status of the left hippocampus determines preoperative verbal memory performance in left mesial temporal lobe epilepsy. Hippocampus 2013; 24:446-54. [DOI: 10.1002/hipo.22238] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/11/2013] [Accepted: 12/11/2013] [Indexed: 11/07/2022]
Affiliation(s)
| | - Roland Coras
- Department of Neuropathology; University Hospital of Erlangen; Erlangen Germany
| | - Johannes Schramm
- Department of Neurosurgery; University Clinic of Bonn; Bonn Germany
| | - Albert J. Becker
- Department of Neuropathology; University Clinic of Bonn; Bonn Germany
| | | | - Ingmar Blümcke
- Department of Neuropathology; University Hospital of Erlangen; Erlangen Germany
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Microtubule-associated proteins in mesial temporal lobe epilepsy with and without psychiatric comorbidities and their relation with granular cell layer dispersion. BIOMED RESEARCH INTERNATIONAL 2013; 2013:960126. [PMID: 24069608 PMCID: PMC3771259 DOI: 10.1155/2013/960126] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/19/2013] [Accepted: 07/24/2013] [Indexed: 11/20/2022]
Abstract
Background. Despite strong association between epilepsy and psychiatric comorbidities, biological substrates are unknown. We have previously reported decreased mossy fiber sprouting in mesial temporal lobe epilepsy (MTLE) patients with psychosis and increased in those with major depression. Microtubule associated proteins (MAPs) are essentially involved in dendritic and synaptic sprouting. Methods. MTLE hippocampi of subjects without psychiatric history, MTLE + major depression, and MTLE + interictal psychosis derived from epilepsy surgery and control necropsies were investigated for neuronal density, granular layer dispersion, and MAP2 and tau immunohistochemistry. Results. Altered MAP2 and tau expression in MTLE and decreased tau expression in MTLE with psychosis were found. Granular layer dispersion correlated inversely with verbal memory scores, and with MAP2 and tau expression in the entorhinal cortex. Patients taking fluoxetine showed increased neuronal density in the granular layer and those taking haloperidol decreased neuronal density in CA3 and subiculum. Conclusions. Our results indicate relations between MAPs, granular layer dispersion, and memory that have not been previously investigated. Differential MAPs expression in human MTLE hippocampi with and without psychiatric comorbidities suggests that psychopathological states in MTLE rely on differential morphological and possibly neurochemical backgrounds. This clinical study was approved by our institution's Research Ethics Board (HC-FMRP no. 1270/2008) and is registered under the Brazilian National System of Information on Ethics in Human Research (SISNEP) no. 0423.0.004.000-07.
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54
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Blümcke I, Thom M, Aronica E, Armstrong DD, Bartolomei F, Bernasconi A, Bernasconi N, Bien CG, Cendes F, Coras R, Cross JH, Jacques TS, Kahane P, Mathern GW, Miyata H, Moshé SL, Oz B, Özkara Ç, Perucca E, Sisodiya S, Wiebe S, Spreafico R. International consensus classification of hippocampal sclerosis in temporal lobe epilepsy: a Task Force report from the ILAE Commission on Diagnostic Methods. Epilepsia 2013; 54:1315-29. [PMID: 23692496 DOI: 10.1111/epi.12220] [Citation(s) in RCA: 670] [Impact Index Per Article: 60.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2013] [Indexed: 12/23/2022]
Abstract
Hippocampal sclerosis (HS) is the most frequent histopathology encountered in patients with drug-resistant temporal lobe epilepsy (TLE). Over the past decades, various attempts have been made to classify specific patterns of hippocampal neuronal cell loss and correlate subtypes with postsurgical outcome. However, no international consensus about definitions and terminology has been achieved. A task force reviewed previous classification schemes and proposes a system based on semiquantitative hippocampal cell loss patterns that can be applied in any histopathology laboratory. Interobserver and intraobserver agreement studies reached consensus to classify three types in anatomically well-preserved hippocampal specimens: HS International League Against Epilepsy (ILAE) type 1 refers always to severe neuronal cell loss and gliosis predominantly in CA1 and CA4 regions, compared to CA1 predominant neuronal cell loss and gliosis (HS ILAE type 2), or CA4 predominant neuronal cell loss and gliosis (HS ILAE type 3). Surgical hippocampus specimens obtained from patients with TLE may also show normal content of neurons with reactive gliosis only (no-HS). HS ILAE type 1 is more often associated with a history of initial precipitating injuries before age 5 years, with early seizure onset, and favorable postsurgical seizure control. CA1 predominant HS ILAE type 2 and CA4 predominant HS ILAE type 3 have been studied less systematically so far, but some reports point to less favorable outcome, and to differences regarding epilepsy history, including age of seizure onset. The proposed international consensus classification will aid in the characterization of specific clinicopathologic syndromes, and explore variability in imaging and electrophysiology findings, and in postsurgical seizure control.
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Affiliation(s)
- Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
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Jafari M, Soerensen J, Bogdanović RM, Dimou L, Götz M, Potschka H. Long-term genetic fate mapping of adult generated neurons in a mouse temporal lobe epilepsy model. Neurobiol Dis 2012; 48:454-63. [DOI: 10.1016/j.nbd.2012.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 06/15/2012] [Accepted: 06/22/2012] [Indexed: 11/25/2022] Open
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56
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Neves RSDC, de Souza Silva Tudesco I, Jardim AP, Caboclo LOSF, Lancellotti C, Ferrari-Marinho T, Hamad AP, Marinho M, Centeno RS, Cavalheiro EA, Scorza CA, Yacubian EMT. Granule cell dispersion is associated with memory impairment in right mesial temporal lobe epilepsy. Seizure 2012; 21:685-90. [DOI: 10.1016/j.seizure.2012.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/13/2012] [Accepted: 07/14/2012] [Indexed: 11/16/2022] Open
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57
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Karádi K, Janszky J, Gyimesi C, Horváth Z, Lucza T, Dóczi T, Kállai J, Abrahám H. Correlation between calbindin expression in granule cells of the resected hippocampal dentate gyrus and verbal memory in temporal lobe epilepsy. Epilepsy Behav 2012; 25:110-9. [PMID: 22796338 DOI: 10.1016/j.yebeh.2012.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 06/05/2012] [Accepted: 06/07/2012] [Indexed: 01/06/2023]
Abstract
Calbindin expression of granule cells of the dentate gyrus is decreased in temporal lobe epilepsy (TLE) regardless of its etiology. In this study, we examined the relation between reduction of calbindin immunoreactivity and the verbal and visuo-spatial memory function of patients with TLE of different etiologies. Significant linear correlation was shown between calbindin expression and short-term and long-term percent retention and retroactive interference in auditory verbal learning test (AVLT) of patients including those with hippocampal sclerosis. In addition, we found significant linear regression between calbindin expression and short-term and long-term percent retention of AVLT in patients whose epilepsy was caused by malformation of cortical development or tumor and when no hippocampal sclerosis and substantial neuronal loss were detected. Together with the role of calbindin in memory established in previous studies on calbindin knock-out mice, our results suggest that reduction of calbindin expression may contribute to memory impairments of patients with TLE, particularly, when neuronal loss is not significant.
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Affiliation(s)
- Kázmér Karádi
- Department of Behavioral Sciences, Faculty of Medicine, University of Pécs, Szigeti u. 12., Pécs 7624, Hungary
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58
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Li LY, Li JL, Zhang HM, Yang WM, Wang K, Fang Y, Wang Y. TGFβ1 treatment reduces hippocampal damage, spontaneous recurrent seizures, and learning memory deficits in pilocarpine-treated rats. J Mol Neurosci 2012; 50:109-23. [PMID: 22936246 DOI: 10.1007/s12031-012-9879-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 08/15/2012] [Indexed: 11/28/2022]
Abstract
Studies have demonstrated the neuroprotective activity of transforming growth factor beta-1 (TGFβ1), protecting neurons against different kinds of insults. However, the role of exogenous TGFβ1 in the neuronal damage following status epilepticus (SE) and the related spontaneous recurrent seizures (SRS) is unknown. The present study aimed to determine the effect of intranasal TGFβ1 administration on SRS and cognitive function following lithium-pilocarpine-induced SE and associated hippocampal damage. We found that intranasal TGFβ1 significantly attenuated the hippocampal insults marked by hematoxylin and eosin, terminal deoxynucleotidyl transferase dUTP nick end labeling, and Fluoro-Jade B staining by 24, 48, and 72 h after SE was induced. The expression of the apoptosis-suppressing protein, Bcl-2, was elevated, whereas the expression of the apoptosis-promoting proteins, Bax and Caspase-3, was suppressed in TGFβ1-treated rats compared to rats without TGFβ1 treatment by 24, 48, and 72 h following induction of SE. The seizure number, severity, and duration of SRS over a 1-month period of monitoring starting 15 days after SE induction as well as the cognitive deficits detected 45 days after SE induction were significantly reduced in TGFβ1-treated rats compared to those without TGFβ1 treatment. Our results indicate that intranasal delivery of TGFβ1 immediately after SE induction not only protected against SRS but also improved cognitive function. The anti-epileptogenic properties of TGFβ1 may be related to its effect of neuroprotection or to its effect of apoptosis pathway changes.
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Affiliation(s)
- Liang-Yong Li
- Epilepsy and Headache Group, Department of Neurology, the First Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
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59
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Blümcke I, Coras R, Miyata H, Ozkara C. Defining clinico-neuropathological subtypes of mesial temporal lobe epilepsy with hippocampal sclerosis. Brain Pathol 2012; 22:402-11. [PMID: 22497612 DOI: 10.1111/j.1750-3639.2012.00583.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hippocampal sclerosis (HS) is the most frequent cause of drug-resistant focal epilepsies (ie, mesial temporal lobe epilepsy with hippocampal sclerosis; mTLE-HS), and presents a broad spectrum of electroclinical, structural and molecular pathology patterns. Many patients become drug resistant during the course of the disease, and surgical treatment was proven helpful to achieve seizure control. Hence, up to 40% of patients suffer from early or late surgical failures. Different patterns of hippocampal cell loss, involvement of other mesial temporal structures, as well as temporal neocortex including focal cortical dysplasia, may contribute to the extent of the epileptogenic network and will be discussed. An international consensus is mandatory to clarify terminology use and to reliably distinguish mTLE-HS subtypes. High-resolution imaging with confirmed histopathologic diagnosis, as well as advanced neurophysiologic and molecular genetic measures, will be a powerful tool in the future to address these issues and help to predict each patient's probability to control their epilepsy in mTLE-HS conditions.
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Affiliation(s)
- Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany.
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60
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Effects of enriched environment in spatial learning and memory of immature rats submitted to early undernourish and seizures. Int J Dev Neurosci 2012; 30:363-7. [DOI: 10.1016/j.ijdevneu.2012.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 01/27/2023] Open
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61
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Martinian L, Catarino C, Thompson P, Sisodiya S, Thom M. Calbindin D28K expression in relation to granule cell dispersion, mossy fibre sprouting and memory impairment in hippocampal sclerosis: A surgical and post mortem series. Epilepsy Res 2012; 98:14-24. [DOI: 10.1016/j.eplepsyres.2011.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/08/2011] [Accepted: 08/14/2011] [Indexed: 12/29/2022]
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62
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63
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Affiliation(s)
- Ciğdem Ozkara
- Department of Neurology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey.
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64
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Helmstaedter C, Witt JA. Clinical neuropsychology in epilepsy: theoretical and practical issues. HANDBOOK OF CLINICAL NEUROLOGY 2012; 107:437-459. [PMID: 22938988 DOI: 10.1016/b978-0-444-52898-8.00036-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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65
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Autobiographical memory in temporal lobe epilepsy: role of hippocampal and temporal lateral structures. Epilepsy Behav 2010; 19:365-71. [PMID: 20875774 DOI: 10.1016/j.yebeh.2010.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 07/10/2010] [Accepted: 07/17/2010] [Indexed: 01/26/2023]
Abstract
The present study was aimed at investigating the impact of hippocampal and temporal cortical lesions on remote autobiographical memories in temporal lobe epilepsy (TLE). Episodic specificity, episodic richness, and personal semantic memory from different life periods were assessed using a modified version of the Autobiographical Memory Interview (AMI) (M.D. Kopelman, A.E. Wilson, A. Baddeley, The autobiographical memory interview. Bury St. Edmunds: Thames Valley Test Co.; 1990) in 47 patients with unilateral mesial or lateral TLE and 38 healthy controls. Patients with TLE performed significantly more poorly than controls. Patients with left and right mTLE were equally moderately impaired, but patients with left lateral TLE had the most severe episodic memory deficits, particularly for childhood memories. With respect to personal semantic memory, patients with left TLE were significantly more impaired than those with right TLE, most pronounced for childhood memories. Both autobiographical memory aspects, episodic and personal semantic memory, were significantly intercorrelated, but both did not correlate with anterograde memory, indicating a structural dissociation between both functions.
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66
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67
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Coras R, Siebzehnrubl FA, Pauli E, Huttner HB, Njunting M, Kobow K, Villmann C, Hahnen E, Neuhuber W, Weigel D, Buchfelder M, Stefan H, Beck H, Steindler DA, Blümcke I. Low proliferation and differentiation capacities of adult hippocampal stem cells correlate with memory dysfunction in humans. Brain 2010; 133:3359-72. [PMID: 20719879 DOI: 10.1093/brain/awq215] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The hippocampal dentate gyrus maintains its capacity to generate new neurons throughout life. In animal models, hippocampal neurogenesis is increased by cognitive tasks, and experimental ablation of neurogenesis disrupts specific modalities of learning and memory. In humans, the impact of neurogenesis on cognition remains unclear. Here, we assessed the neurogenic potential in the human hippocampal dentate gyrus by isolating adult human neural stem cells from 23 surgical en bloc hippocampus resections. After proliferation of the progenitor cell pool in vitro we identified two distinct patterns. Adult human neural stem cells with a high proliferation capacity were obtained in 11 patients. Most of the cells in the high proliferation capacity cultures were capable of neuronal differentiation (53 ± 13% of in vitro cell population). A low proliferation capacity was observed in 12 specimens, and only few cells differentiated into neurons (4 ± 2%). This was reflected by reduced numbers of proliferating cells in vivo as well as granule cells immunoreactive for doublecortin, brain-derived neurotrophic factor and cyclin-dependent kinase 5 in the low proliferation capacity group. High and low proliferation capacity groups differed dramatically in declarative memory tasks. Patients with high proliferation capacity stem cells had a normal memory performance prior to epilepsy surgery, while patients with low proliferation capacity stem cells showed severe learning and memory impairment. Histopathological examination revealed a highly significant correlation between granule cell loss in the dentate gyrus and the same patient's regenerative capacity in vitro (r = 0.813; P < 0.001; linear regression: R²(adjusted) = 0.635), as well as the same patient's ability to store and recall new memories (r = 0.966; P = 0.001; linear regression: R²(adjusted) = 0.9). Our results suggest that encoding new memories is related to the regenerative capacity of the hippocampus in the human brain.
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Affiliation(s)
- Roland Coras
- University Hospital Erlangen, Schwabachanlage 6, D - 91054 Erlangen, Germany
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68
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Morasch KC, Bell MA. Patterns of brain-electrical activity during declarative memory performance in 10-month-old infants. Brain Cogn 2009; 71:215-22. [DOI: 10.1016/j.bandc.2009.08.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 06/18/2009] [Accepted: 08/26/2009] [Indexed: 10/20/2022]
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69
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Blümcke I. Neuropathology of focal epilepsies: a critical review. Epilepsy Behav 2009; 15:34-9. [PMID: 19248840 DOI: 10.1016/j.yebeh.2009.02.033] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 02/19/2009] [Indexed: 01/05/2023]
Abstract
A broad spectrum of structural lesions can be histopathologically identified in surgical brain specimens obtained from patients with focal, therapy-refractory epilepsies. In our experience with 4512 tissue samples collected at the German Neuropathological Reference Center for Epilepsy Surgery, three clinicopathological entities are most common: mesial temporal sclerosis (40%), long-term epilepsy-associated tumors (27%), and malformations of cortical development (13%). Notwithstanding, a systematic histopathological and molecular-genetic analysis is mandatory to unravel the underlying pathogenic mechanism of epilepsy-associated lesions and may contribute to our current understanding of pharmacoresistance and epileptogenesis. However, an interdisciplinary approach is necessary to further explore predictive parameters with respect to postsurgical seizure relief and memory impairment, and also to identify new pharmacological targets.
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Affiliation(s)
- Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, D-91054 Erlangen, Germany.
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70
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Towards a clinico-pathological classification of granule cell dispersion in human mesial temporal lobe epilepsies. Acta Neuropathol 2009; 117:535-44. [PMID: 19277686 DOI: 10.1007/s00401-009-0512-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 03/02/2009] [Accepted: 03/02/2009] [Indexed: 10/21/2022]
Abstract
The dentate gyrus (DG) plays a pivotal role in the functional and anatomical organization of the hippocampus and is involved in learning and memory formation. However, the impact of structural DG abnormalities, i.e., granule cell dispersion (GCD), for hippocampal seizure susceptibility and its association with distinct lesion patterns in epileptic disorders, such as mesial temporal sclerosis (MTS) remains enigmatic and a large spectrum of pathological changes has been recognized. Here, we propose a clinico-pathological classification of DG pathology based on the examination of 96 surgically resected hippocampal specimens obtained from patients with chronic temporal lobe epilepsy (TLE). We observed three different histological patterns. (1) A normal granule cell layer was identified in 11 patients (no-GCP; 18.7%). (2) Substantial granule cell loss was evident in 36 patients (referred to as granule cell pathology (GCP) Type 1; 37.5%). (3) Architectural abnormalities were observed in 49 specimens, including one or more of the following features: granule cell dispersion, ectopic neurons or clusters of neurons in the molecular layer, or bi-lamination (GCP Type 2; 51%). Cell loss was always encountered in this latter cohort. Seventy-eight patients of our present series suffered from MTS (81.3%). Intriguingly, all MTS patients displayed a compromised DG, 31 (40%) with significant cell loss (Type 1) and 47 (60%) with GCD (Type 2). In 18 patients without MTS (18.7%), seven displayed focally restricted DG abnormalities, either cell loss (n = 5) or GCD (n = 2). Clinical histories revealed a significant association between DG pathology patterns and higher age at epilepsy surgery (p = 0.008), longer epilepsy duration (p = 0.004), but also with learning dysfunction (p < 0.05). There was no correlation with the extent of pyramidal cell loss in adjacent hippocampal segments nor with postsurgical seizure relief. The association with long-term seizure histories and cognitive dysfunction is remarkable and may point to a compromised regenerative capacity of the DG in this cohort of TLE patients.
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71
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Increased reelin promoter methylation is associated with granule cell dispersion in human temporal lobe epilepsy. J Neuropathol Exp Neurol 2009; 68:356-64. [PMID: 19287316 DOI: 10.1097/nen.0b013e31819ba737] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Mesial temporal sclerosis (MTS) is the most common lesion in chronic, intractable temporal lobe epilepsies (TLE) and characterized by segmental neuronal cell loss in major hippocampal segments. Another histopathological hallmark includes granule cell dispersion (GCD), an architectural disturbance of the dentate gyrus encountered in approximately 50% of patients with mesial temporal sclerosis. Reelin, which plays a key role during hippocampal development and maintenance of laminar organization, is synthesized and released by Cajal-Retzius cells of the dentate molecular layer, and previous studies have shown that Reelin transcript levels are downregulated in human temporal lobe epilepsies specimens. To investigate whether epigenetic silencing by Reelin promoter methylation may be an underlying pathogenetic mechanism of GCD, DNA was harvested from 3 microdissected hippocampal subregions (i.e. molecular and granule cell layers of the dentate gyrus and presubiculum) from 8 MTS specimens with GCD, 5 TLE samples without GCD, and 3 autopsy controls. Promoter methylation was analyzed after bisulfite treatment, cloning, and direct sequencing; immunohistochemistry was performed to identify Cajal-Retzius cells. Reelin promoter methylation was found to be greater in TLE specimens than in controls; promoter methylation correlated with GCD among TLE specimens (p < 0.0002). No other clinical or histopathological parameter (i.e. sex, age, seizure duration, medication or extent, of MTS) correlated with promoter methylation. These data support a compromised Reelin-signaling pathway and identify promoter methylation as an epigenetic mechanism in the pathogenesis of TLE.
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72
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Sun QJ, Duan RS, Wang AH, Shang W, Zhang T, Zhang XQ, Chi ZF. Alterations of NR2B and PSD-95 expression in hippocampus of kainic acid-exposed rats with behavioural deficits. Behav Brain Res 2009; 201:292-9. [PMID: 19428647 DOI: 10.1016/j.bbr.2009.02.027] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 02/19/2009] [Accepted: 02/24/2009] [Indexed: 10/21/2022]
Abstract
Temporal lobe epilepsy (TLE), characterized by spontaneous recurrent seizure (SRS), is associated with behavioural problems, but the underlying molecular mechanisms have not been clearly identified. In the present study, kainic acid (KA) was administered systemically in adult male Wistar rats to induce SRS. Behavioural performance analyses at 2, 4, and 6 weeks post-status epilepticus (post-SE) showed spatial learning memory deficit, anxiety and increased locomotor activity in rats with long-term SRS compared with rats without SRS after normal saline (NS) or KA-valproate (KA-VPA) treatment. No neuronal cell loss was observed in the hippocampus at 6 weeks post-SE. Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot analyses revealed that down-regulation of NMDA receptor subunit 2B (NR2B) and postsynaptic density protein-95 (PSD-95) expression in adult hippocampus was found at 4 weeks post-SE and a further decrease at 6 weeks post-SE compared with rats without SRS after NS or KA-VPA treatment. Furthermore, the decreased expression of NR2B and PSD-95 was correlated with the representatively behavioural deficit. These findings suggest that long-term SRS might decrease NR2B/PSD-95 expression in adult hippocampus and consequently cause behavioural deficits, including spatial learning memory deficit, anxiety and increased locomotor activity. Maintaining the expression of NR2B/PSD-95 might partially contribute to the normal behaviour in rats with long-term SRS.
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Affiliation(s)
- Qin-Jian Sun
- Department of Neurology, Qianfoshan Hospital, Shandong University, 66 Jingshi Road, Jinan, Shandong 250014, PR China.
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Jacobs MP, Leblanc GG, Brooks-Kayal A, Jensen FE, Lowenstein DH, Noebels JL, Spencer DD, Swann JW. Curing epilepsy: progress and future directions. Epilepsy Behav 2009; 14:438-45. [PMID: 19341977 PMCID: PMC2822433 DOI: 10.1016/j.yebeh.2009.02.036] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 02/14/2009] [Indexed: 01/10/2023]
Abstract
During the past decade, substantial progress has been made in delineating clinical features of the epilepsies and the basic mechanisms responsible for these disorders. Eleven human epilepsy genes have been identified and many more are now known from animal models. Candidate targets for cures are now based upon newly identified cellular and molecular mechanisms that underlie epileptogenesis. However, epilepsy is increasingly recognized as a group of heterogeneous syndromes characterized by other conditions that co-exist with seizures. Cognitive, emotional and behavioral co-morbidities are common and offer fruitful areas for study. These advances in understanding mechanisms are being matched by the rapid development of new diagnostic methods and therapeutic approaches. This article reviews these areas of progress and suggests specific goals that once accomplished promise to lead to cures for epilepsy.
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Affiliation(s)
- Margaret P. Jacobs
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville, MD, USA
| | - Gabrielle G. Leblanc
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville, MD, USA
| | - Amy Brooks-Kayal
- Neurology and Pediatrics, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Dan H. Lowenstein
- Department of Neurology, Box 0114, University of California, San Francisco, San Francisco, CA, USA
| | | | - Dennis D. Spencer
- Department of Neurosurgery, Yale University, School of Medicine, New Haven, CT, USA
| | - John W. Swann
- Baylor College of Medicine, Texas Children’s Hospital, Houston, TX, USA
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74
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Kuruba R, Hattiangady B, Shetty AK. Hippocampal neurogenesis and neural stem cells in temporal lobe epilepsy. Epilepsy Behav 2009; 14 Suppl 1:65-73. [PMID: 18796338 PMCID: PMC2654382 DOI: 10.1016/j.yebeh.2008.08.020] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 08/28/2008] [Accepted: 08/29/2008] [Indexed: 12/12/2022]
Abstract
Virtually all mammals, including humans, exhibit neurogenesis throughout life in the hippocampus, a learning and memory center in the brain. Numerous studies in animal models imply that hippocampal neurogenesis is important for functions such as learning, memory, and mood. Interestingly, hippocampal neurogenesis is very sensitive to physiological and pathological stimuli. Certain pathological stimuli such as seizures alter both the amount and the pattern of neurogenesis, though the overall effect depends on the type of seizures. Acute seizures are classically associated with augmentation of neurogenesis and migration of newly born neurons into ectopic regions such as the hilus and the molecular layer of the dentate gyrus. Additional studies suggest that abnormally migrated newly born neurons play a role in the occurrence of epileptogenic hippocampal circuitry characteristically seen after acute seizures, status epilepticus, or head injury. Recurrent spontaneous seizures such as those typically observed in chronic temporal lobe epilepsy are associated with substantially reduced neurogenesis, which, interestingly, coexists with learning and memory impairments and depression. In this review, we discuss both the extent and the potential implications of abnormal hippocampal neurogenesis induced by acute seizures as well as recurrent spontaneous seizures. We also discuss the consequences of chronic spontaneous seizures on differentiation of neural stem cell progeny in the hippocampus and strategies that are potentially useful for normalizing neurogenesis in chronic temporal lobe epilepsy.
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Affiliation(s)
- Ramkumar Kuruba
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710,Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705
| | - Bharathi Hattiangady
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710,Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705
| | - Ashok K. Shetty
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710,Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705,Correspondence should be addressed to: Ashok K. Shetty, M.Sc., Ph.D., Professor, Division of Neurosurgery, Box 3807, Duke University Medical Center, Durham NC 27710, Phone: 919-286-0411, Ext. 7096, E-mail:
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75
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Bengner T, Siemonsen S, Stodieck S, Fiehler J. T2 relaxation time correlates of face recognition deficits in temporal lobe epilepsy. Epilepsy Behav 2008; 13:670-7. [PMID: 18722550 DOI: 10.1016/j.yebeh.2008.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 08/03/2008] [Accepted: 08/07/2008] [Indexed: 11/15/2022]
Abstract
This study explored structural correlates of immediate and delayed face recognition in 22 nonsurgical patients with nonlesional, unilateral mesial temporal lobe epilepsy (TLE, 10 left/12 right). We measured T2 relaxation time bilaterally in the hippocampus, the amygdala, and the fusiform gyrus. Apart from raised T2 values in the ipsilateral hippocampus, we found increased T2 values in the ipsilateral amygdala. Patients with right TLE exhibited impaired face recognition as a result of a decrease from immediate to delayed recognition. Higher T2 values in the right than left fusiform gyrus or hippocampus were related to worse immediate face recognition, but did not correlate with 24-hour face recognition. These preliminary results indicate that structural changes in the fusiform gyrus and hippocampus may influence immediate face recognition deficits, but have no linear influence on long-term face recognition in TLE. We suggest that long-term face recognition depends on a right hemispheric network encompassing structures outside the temporal lobe.
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Affiliation(s)
- Thomas Bengner
- Evangelisches Krankenhaus Alsterdorf gGmbH, Abteilung für Neurologie und Epileptologie, Hamburg, Germany.
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76
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Butler CR, Zeman AZ. Recent insights into the impairment of memory in epilepsy: transient epileptic amnesia, accelerated long-term forgetting and remote memory impairment. Brain 2008; 131:2243-63. [DOI: 10.1093/brain/awn127] [Citation(s) in RCA: 230] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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77
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78
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Siebzehnrubl FA, Blumcke I. Neurogenesis in the human hippocampus and its relevance to temporal lobe epilepsies. Epilepsia 2008; 49 Suppl 5:55-65. [PMID: 18522601 DOI: 10.1111/j.1528-1167.2008.01638.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ample evidence points to the dentate gyrus as anatomical region for persistent neurogenesis in the adult mammalian brain. This has been confirmed in a variety of animal models under physiological as well as pathophysiological conditions. Notwithstanding, similar experiments are difficult to perform in humans. Postmortem studies demonstrated persisting neurogenesis in the elderly human brain. In addition, neural precursor cells can be isolated from surgical specimens obtained from patients with intractable temporal lobe epilepsy (TLE) and propagated or differentiated into neuronal and glial lineages. It remains a controversial issue, whether epileptic seizures have an effect on or even increase hippocampal neurogenesis in humans. Recent data support the notion that seizures induce neurogenesis in young patients, whereas the capacity of neuronal recruitment and proliferation decreases with age. Animal models of TLE further indicate that these newly generated neurons integrate into epileptogenic networks and contribute to increased seizure susceptibility. However, pathomorphological disturbances within the epileptic hippocampus, such as granule cell dispersion (GCD), may not directly result from compromised neurogenesis. Still, the majority of adult TLE patients present with significant dentate granule cell loss at an end stage of the disease, which relates to severe memory and learning disabilities. In conclusion, surgical specimens obtained from TLE patients represent an important tool to study mechanisms of stem cell recruitment, proliferation and differentiation in the human brain. In addition, increasing availability of surgical specimens opens new avenues to systematically explore disease pathomechanisms in chronic epilepsies.
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Hammen T, Hildebrandt M, Stadlbauer A, Doelken M, Engelhorn T, Kerling F, Kasper B, Romstoeck J, Ganslandt O, Nimsky C, Blumcke I, Doerfler A, Stefan H. Non-invasive detection of hippocampal sclerosis: correlation between metabolite alterations detected by (1)H-MRS and neuropathology. NMR IN BIOMEDICINE 2008; 21:545-552. [PMID: 18035849 DOI: 10.1002/nbm.1222] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We assessed (1)H-MRS as a screening tool for detection of hippocampal sclerosis in patients with temporal lobe epilepsy (TLE). (1)H-MRS was carried out in the hippocampus of 23 patients with unilateral TLE. Metabolite alterations detected by (1)H-MRS correlated with degree of segmental neuronal cell loss and amount of astrogliosis. Positive correlation was found between total N-Acetylaspartate (tNAA) reduction and neuronal density in hippocampal CA1 (P < 0.001), CA3 (P = 0.015), and CA4 subfields (P = 0.031) and the dentate gyrus (P = 0.006). Neuronal cell loss in CA1 turned out to be the most predictive and only significant variable for tNAA reduction (P = 0.027). The association between myo-inositol (m-Ins) and astroglial glial fibrillary acidic protein (GFAP) expression revealed significantly increased m-Ins concentrations associated with diffuse astrogliosis (m-Ins = 6.4 +/- 1.1 institutional units) compared with gliosis restricted to isolated sectors of the hippocampus (i.e. hilus) (m-Ins = 5.2 +/- 1.2 institutional units) (P = 0.039). A negative correlation was found between m-Ins and neuronal loss in the CA4 subfield of the hippocampus (P = 0.028). Our results support (1)H-MRS as a suitable non-invasive method for preoperative identification of hippocampal sclerosis in patients with TLE. The extent of tNAA reduction correlates with hippocampal neuronal cell density. Furthermore, m-Ins is associated with the extent of hippocampal astrogliosis.
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Affiliation(s)
- Thilo Hammen
- Center Epilepsy Erlangen (ZEE), Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany.
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80
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Carpentino JE, Hartman NW, Grabel LB, Naegele JR. Region-specific differentiation of embryonic stem cell-derived neural progenitor transplants into the adult mouse hippocampus following seizures. J Neurosci Res 2008; 86:512-24. [DOI: 10.1002/jnr.21514] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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81
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Kim SH, Cho YJ, Seok Kim H, Heo K, Lee MC, Lee BI, Seung Kim T, Woo Chang J. Balloon cells and dysmorphic neurons in the hippocampus associated with epileptic amnesic syndrome: a case report. Epilepsia 2008; 49:905-9. [PMID: 18266753 DOI: 10.1111/j.1528-1167.2007.01527.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recently, we encountered a 39-year-old woman with typical epileptic amnesic syndrome. The patient underwent right anterior temporal lobectomy, which removed the right hippocampus. The patient's resected hippocampus showed typical histological features of Ammon's horn sclerosis (AHS) with dysmorphic neurons. In addition, the prominent balloon cells, admixed with dysmorphic neurons, were noted in the hippocampus. To our knowledge, this is the first reported case showing AHS with balloon cells. The presence of balloon cells reinforces the hypothesis that AHS itself might be a maldevelopment disorder.
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Affiliation(s)
- Se Hoon Kim
- Department of Pathology, College of Medicine, Yonsei University, Seoul, Korea
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Zhou JL, Shatskikh TN, Liu X, Holmes GL. Impaired single cell firing and long-term potentiation parallels memory impairment following recurrent seizures. Eur J Neurosci 2007; 25:3667-77. [PMID: 17610586 DOI: 10.1111/j.1460-9568.2007.05598.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Patients with epilepsy are at substantial risk for memory impairment. Animal studies have paralleled these clinical observations, demonstrating impaired hippocampal function as measured by spatial memory in rodents subjected to seizures. However, the mechanism of seizure-induced hippocampal impairment is unclear. Here we investigated the effects of recurrent seizures on water-maze performance, a behavioural measure of learning and memory, long-term potentiation (LTP; considered a test of synaptic plasticity and memory) and place-cell firing patterns, a single-cell indicator of spatial memory. LTP and CA1 place-cell activity were examined in separate groups of freely moving rats, before and after 10 flurothyl-induced seizures. Water maze performance was examined in a third group of rats, five with previously induced seizures and five controls. Recurrent flurothyl seizures were associated with marked impairment in LTP and a reduction in the frequency of the peak theta power. Compared to baseline recordings, place-cell firing patterns following recurrent seizures were significantly less precise, had lower firing rates and were less stable. Impaired place-cell firing was seen as early as after two seizures and persisted at least 72 h after the last seizure. Water-maze performance was also significantly impaired in animals that underwent recurrent seizures. No cell loss or synaptic reorganization was observed in the hippocampus or in several other cortical areas that are vulnerable to seizures. These results demonstrate that relatively brief excitatory events, not producing visible cell damage, can nevertheless cause long-lasting changes in hippocampal physiology, observable as impairments in place-cell function, LTP and spatial memory.
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Affiliation(s)
- Jun-Li Zhou
- Neuroscience Center at Dartmouth, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, New Hampshire 03756, USA
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