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Höller Y, Trinka E. Is There a Relation between EEG-Slow Waves and Memory Dysfunction in Epilepsy? A Critical Appraisal. Front Hum Neurosci 2015; 9:341. [PMID: 26124717 PMCID: PMC4463866 DOI: 10.3389/fnhum.2015.00341] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/28/2015] [Indexed: 12/12/2022] Open
Abstract
Is there a relationship between peri-ictal slow waves, loss of consciousness, memory, and slow-wave sleep, in patients with different forms of epilepsy? We hypothesize that mechanisms, which result in peri-ictal slow-wave activity as detected by the electroencephalogram, could negatively affect memory processes. Slow waves (≤4 Hz) can be found in seizures with impairment of consciousness and also occur in focal seizures without impairment of consciousness but with inhibited access to memory functions. Peri-ictal slow waves are regarded as dysfunctional and are probably caused by mechanisms, which are essential to disturb the consolidation of memory entries in these patients. This is in strong contrast to physiological slow-wave activity during deep sleep, which is thought to group memory-consolidating fast oscillatory activity. In patients with epilepsy, slow waves may not only correlate with the peri-ictal clouding of consciousness, but could be the epiphenomenon of mechanisms, which interfere with normal brain function in a wider range. These mechanisms may have transient impacts on memory, such as temporary inhibition of memory systems, altered patterns of hippocampal-neocortical interactions during slow-wave sleep, or disturbed cross-frequency coupling of slow and fast oscillations. In addition, repeated tonic-clonic seizures over the years in uncontrolled chronic epilepsy may cause a progressive cognitive decline. This hypothesis can only be assessed in long-term prospective studies. These studies could disentangle the reversible short-term impacts of seizures, and the impacts of chronic uncontrolled seizures. Chronic uncontrolled seizures lead to irreversible memory impairment. By contrast, short-term impacts do not necessarily lead to a progressive cognitive decline but result in significantly impaired peri-ictal memory performance.
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Affiliation(s)
- Yvonne Höller
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University, Salzburg, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University, Salzburg, Austria
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Hsiao FJ, Yu HY, Chen WT, Kwan SY, Chen C, Yen DJ, Yiu CH, Shih YH, Lin YY. Increased Intrinsic Connectivity of the Default Mode Network in Temporal Lobe Epilepsy: Evidence from Resting-State MEG Recordings. PLoS One 2015; 10:e0128787. [PMID: 26035750 PMCID: PMC4452781 DOI: 10.1371/journal.pone.0128787] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 04/30/2015] [Indexed: 11/23/2022] Open
Abstract
The electrophysiological signature of resting state oscillatory functional connectivity within the default mode network (DMN) during spike-free periods in temporal lobe epilepsy (TLE) remains unclear. Using magnetoencephalographic (MEG) recordings, this study investigated how the connectivity within the DMN was altered in TLE, and we examined the effect of lateralized TLE on functional connectivity. Sixteen medically intractable TLE patients and 22 controls participated in this study. Whole-scalp 306-channel MEG epochs without interictal spikes generated from both MEG and EEG data were analyzed using a minimum norm estimate (MNE) and source-based imaginary coherence analysis. With this processing, we obtained the cortical activation and functional connectivity within the DMN. The functional connectivity was increased between DMN and the right medial temporal (MT) region at the delta band and between DMN and the bilateral anterior cingulate cortex (ACC) regions at the theta band. The functional change was associated with the lateralization of TLE. The right TLE showed enhanced DMN connectivity with the right MT while the left TLE demonstrated increased DMN connectivity with the bilateral MT. There was no lateralization effect of TLE upon the DMN connectivity with ACC. These findings suggest that the resting-state functional connectivity within the DMN is reinforced in temporal lobe epilepsy during spike-free periods. Future studies are needed to examine if the altered functional connectivity can be used as a biomarker for treatment responses, cognitive dysfunction and prognosis in patients with TLE.
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Affiliation(s)
- Fu-Jung Hsiao
- Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan
- Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
- Laboratory of Neurophysiology at Medical Research Division, Taipei Veterans General Hospital, Taipei, Taiwan
- * E-mail: (FJH); (YYL)
| | - Hsiang-Yu Yu
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wei-Ta Chen
- Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Laboratory of Neurophysiology at Medical Research Division, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shang-Yeong Kwan
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chien Chen
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Der-Jen Yen
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chun-Hing Yiu
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yang-Hsin Shih
- Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurosurgery, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yung-Yang Lin
- Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan
- Laboratory of Neurophysiology at Medical Research Division, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
- * E-mail: (FJH); (YYL)
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Tsai ML, Hung KL, Tsan YY, Tung WTH. Long-term neurocognitive outcome and auditory event-related potentials after complex febrile seizures in children. Epilepsy Behav 2015; 47:55-60. [PMID: 26043164 DOI: 10.1016/j.yebeh.2015.04.067] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 12/15/2022]
Abstract
OBJECTIVES Whether prolonged or complex febrile seizures (FS) produce long-term injury to the hippocampus is a critical question concerning the neurocognitive outcome of these seizures. Long-term event-related evoked potential (ERP) recording from the scalp is a noninvasive technique reflecting the sensory and cognitive processes associated with attention tasks. This study aimed to investigate the long-term outcome of neurocognitive and attention functions and evaluated auditory event-related potentials in children who have experienced complex FS in comparison with other types of FS. METHODS One hundred and forty-seven children aged more than 6 years who had experienced complex FS, simple single FS, simple recurrent FS, or afebrile seizures (AFS) after FS and age-matched healthy controls were enrolled. Patients were evaluated with Wechsler Intelligence Scale for Children (WISC; Chinese WISC-IV) scores, behavior test scores (Chinese version of Conners' continuous performance test, CPT II V.5), and behavior rating scales. Auditory ERPs were recorded in each patient. RESULTS Patients who had experienced complex FS exhibited significantly lower full-scale intelligence quotient (FSIQ), perceptual reasoning index, and working memory index scores than did the control group but did not show significant differences in CPT scores, behavior rating scales, or ERP latencies and amplitude compared with the other groups with FS. We found a significant decrease in the FSIQ and four indices of the WISC-IV, higher behavior rating scales, a trend of increased CPT II scores, and significantly delayed P300 latency and reduced P300 amplitude in the patients with AFS after FS. CONCLUSION We conclude that there is an effect on cognitive function in children who have experienced complex FS and patients who developed AFS after FS. The results indicated that the WISC-IV is more sensitive in detecting cognitive abnormality than ERP. Cognition impairment, including perceptual reasoning and working memory defects, was identified in patients with prolonged, multiple, or focal FS. These results may have implications for the pathogenesis of complex FS. Further comprehensive psychological evaluation and educational programs are suggested.
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Affiliation(s)
- Min-Lan Tsai
- Department of Pediatrics, Cheng-Hsin General Hospital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
| | - Kun-Long Hung
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan; School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan
| | - Ying-Ying Tsan
- Department of Psychiatry, Cathay General Hospital, Taipei, Taiwan
| | - William Tao-Hsin Tung
- School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan; Department of Medical Research and Education, Cheng-Hsin General Hospital, Taipei, Taiwan
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Artinian J, Peret A, Mircheva Y, Marti G, Crépel V. Impaired neuronal operation through aberrant intrinsic plasticity in epilepsy. Ann Neurol 2015; 77:592-606. [PMID: 25583290 DOI: 10.1002/ana.24348] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 10/30/2014] [Accepted: 12/10/2014] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Patients with temporal lobe epilepsy often display cognitive comorbidity with recurrent seizures. However, the cellular mechanisms underlying the impairment of neuronal information processing remain poorly understood in temporal lobe epilepsy. Within the hippocampal formation neuronal networks undergo major reorganization, including the sprouting of mossy fibers in the dentate gyrus; they establish aberrant recurrent synapses between dentate granule cells and operate via postsynaptic kainate receptors. In this report, we tested the hypothesis that this aberrant local circuit alters information processing of perforant path inputs constituting the major excitatory afferent pathway from entorhinal cortex to dentate granule cells. METHODS Experiments were performed in dentate granule cells from control rats and rats with temporal lobe epilepsy induced by pilocarpine hydrochloride treatment. Neurons were recorded in patch clamp in whole cell configuration in hippocampal slices. RESULTS Our present data revealed that an aberrant readout of synaptic inputs by kainate receptors triggered a long-lasting impairment of the perforant path input-output operation in epileptic dentate granule cells. We demonstrated that this is due to the aberrant activity-dependent potentiation of the persistent sodium current altering intrinsic firing properties of dentate granule cells. INTERPRETATION We propose that this aberrant activity-dependent intrinsic plasticity, which lastingly impairs the information processing of cortical inputs in dentate gyrus, may participate in hippocampal-related cognitive deficits, such as those reported in patients with epilepsy.
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Affiliation(s)
- Julien Artinian
- Mediterranean Institute of Neurobiology, National Institute of Health and Medical Research, Marseille, France; Aix-Marseille University, Marseille, France
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Hubens CJ, Kaptein PS, ter Horst JP, Voskuyl RA, Schenk GJ. Kainate-induced epileptogenesis alters circular hole board learning strategy but not the performance of C57BL/6J mice. Epilepsy Behav 2014; 41:127-35. [PMID: 25461204 DOI: 10.1016/j.yebeh.2014.09.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 09/12/2014] [Indexed: 01/12/2023]
Abstract
Patients with mesial temporal lobe epilepsy (mTLE) frequently show cognitive deficits. However, the relation between mTLE and cognitive impairment is poorly understood. To gain more insight into epilepsy-associated alterations in cognitive performance, we studied the spatial learning of C57BL/6J mice five weeks after kainate-induced status epilepticus (SE). Typically, structural hippocampal rearrangements take place within five weeks after SE. Mice were monitored by exposing them to four tasks with a focus on spatial memory and anxiety: the circular hole board, modified hole board, novel object-placement task, and elevated plus maze. On the circular hole board, animals showed a higher preference for hippocampus-independent strategies after SE. In contrast, no change in strategy was seen on the modified hole board, but animals with SE were able to finish the task more often. Animals did not have an increased preference for a relocated object in the novel object-placement task but showed an increased locomotion after SE. No indications for altered anxiety were found when tested on the elevated plus maze following SE. These data suggest that the circular hole board is a well-suited paradigm to detect subtle SE-induced hippocampal deficits.
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Affiliation(s)
- Chantal J Hubens
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands; Department of Pharmacology, Leiden Academic Center for Drug Research (LACDR), Leiden, The Netherlands.
| | - Pascale S Kaptein
- Department of Pharmacology, Leiden Academic Center for Drug Research (LACDR), Leiden, The Netherlands
| | - Judith P ter Horst
- Department of Medical Pharmacology, Leiden University Medical Center (LUMC) & LACDR, Leiden, The Netherlands
| | - Rob A Voskuyl
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands; Department of Pharmacology, Leiden Academic Center for Drug Research (LACDR), Leiden, The Netherlands
| | - Geert J Schenk
- Department of Medical Pharmacology, Leiden University Medical Center (LUMC) & LACDR, Leiden, The Netherlands
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Inada C, Niu Y, Matsumoto K, Le XT, Fujiwara H. Possible involvement of VEGF signaling system in rescuing effect of endogenous acetylcholine on NMDA-induced long-lasting hippocampal cell damage in organotypic hippocampal slice cultures. Neurochem Int 2014; 75:39-47. [DOI: 10.1016/j.neuint.2014.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 05/22/2014] [Accepted: 05/24/2014] [Indexed: 01/17/2023]
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Levite M. Glutamate receptor antibodies in neurological diseases: anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies, anti-NMDA-NR2A/B antibodies, anti-mGluR1 antibodies or anti-mGluR5 antibodies are present in subpopulations of patients with either: epilepsy, encephalitis, cerebellar ataxia, systemic lupus erythematosus (SLE) and neuropsychiatric SLE, Sjogren's syndrome, schizophrenia, mania or stroke. These autoimmune anti-glutamate receptor antibodies can bind neurons in few brain regions, activate glutamate receptors, decrease glutamate receptor's expression, impair glutamate-induced signaling and function, activate blood brain barrier endothelial cells, kill neurons, damage the brain, induce behavioral/psychiatric/cognitive abnormalities and ataxia in animal models, and can be removed or silenced in some patients by immunotherapy. J Neural Transm (Vienna) 2014; 121:1029-75. [PMID: 25081016 DOI: 10.1007/s00702-014-1193-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 03/08/2014] [Indexed: 12/23/2022]
Abstract
Glutamate is the major excitatory neurotransmitter of the Central Nervous System (CNS), and it is crucially needed for numerous key neuronal functions. Yet, excess glutamate causes massive neuronal death and brain damage by excitotoxicity--detrimental over activation of glutamate receptors. Glutamate-mediated excitotoxicity is the main pathological process taking place in many types of acute and chronic CNS diseases and injuries. In recent years, it became clear that not only excess glutamate can cause massive brain damage, but that several types of anti-glutamate receptor antibodies, that are present in the serum and CSF of subpopulations of patients with a kaleidoscope of human neurological diseases, can undoubtedly do so too, by inducing several very potent pathological effects in the CNS. Collectively, the family of anti-glutamate receptor autoimmune antibodies seem to be the most widespread, potent, dangerous and interesting anti-brain autoimmune antibodies discovered up to now. This impression stems from taking together the presence of various types of anti-glutamate receptor antibodies in a kaleidoscope of human neurological and autoimmune diseases, their high levels in the CNS due to intrathecal production, their multiple pathological effects in the brain, and the unique and diverse mechanisms of action by which they can affect glutamate receptors, signaling and effects, and subsequently impair neuronal signaling and induce brain damage. The two main families of autoimmune anti-glutamate receptor antibodies that were already found in patients with neurological and/or autoimmune diseases, and that were already shown to be detrimental to the CNS, include the antibodies directed against ionotorpic glutamate receptors: the anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies and anti-NMDA-NR2 antibodies, and the antibodies directed against Metabotropic glutamate receptors: the anti-mGluR1 antibodies and the anti-mGluR5 antibodies. Each type of these anti-glutamate receptor antibodies is discussed separately in this very comprehensive review, with regards to: the human diseases in which these anti-glutamate receptor antibodies were found thus far, their presence and production in the nervous system, their association with various psychiatric/behavioral/cognitive/motor impairments, their possible association with certain infectious organisms, their detrimental effects in vitro as well as in vivo in animal models in mice, rats or rabbits, and their diverse and unique mechanisms of action. The review also covers the very encouraging positive responses to immunotherapy of some patients that have either of the above-mentioned anti-glutamate receptor antibodies, and that suffer from various neurological diseases/problems. All the above are also summarized in the review's five schematic and useful figures, for each type of anti-glutamate receptor antibodies separately. The review ends with a summary of all the main findings, and with recommended guidelines for diagnosis, therapy, drug design and future investigations. In the nut shell, the human studies, the in vitro studies, as well as the in vivo studies in animal models in mice, rats and rabbit revealed the following findings regarding the five different types of anti-glutamate receptor antibodies: (1) Anti-AMPA-GluR3B antibodies are present in ~25-30% of patients with different types of Epilepsy. When these anti-glutamate receptor antibodies (or other types of autoimmune antibodies) are found in Epilepsy patients, and when these autoimmune antibodies are suspected to induce or aggravate the seizures and/or the cognitive/psychiatric/behavioral impairments that sometimes accompany the seizures, the Epilepsy is called 'Autoimmune Epilepsy'. In some patients with 'Autoimmune Epilepsy' the anti-AMPA-GluR3B antibodies associate significantly with psychiatric/cognitive/behavior abnormalities. In vitro and/or in animal models, the anti-AMPA-GluR3B antibodies by themselves induce many pathological effects: they activate glutamate/AMPA receptors, kill neurons by 'Excitotoxicity', and/or by complement activation modulated by complement regulatory proteins, cause multiple brain damage, aggravate chemoconvulsant-induced seizures, and also induce behavioral/motor impairments. Some patients with 'Autoimmune Epilepsy' that have anti-AMPA-GluR3B antibodies respond well (although sometimes transiently) to immunotherapy, and thanks to that have reduced seizures and overall improved neurological functions. (2) Anti-NMDA-NR1 antibodies are present in patients with autoimmune 'Anti-NMDA-receptor Encephalitis'. In humans, in animal models and in vitro the anti-NMDA-NR1 antibodies can be very pathogenic since they can cause a pronounced decrease of surface NMDA receptors expressed in hippocampal neurons, and also decrease the cluster density and synaptic localization of the NMDA receptors. The anti-NMDA-NR1 antibodies induce these effects by crosslinking and internalization of the NMDA receptors. Such changes can impair glutamate signaling via the NMDA receptors and lead to various neuronal/behavior/cognitive/psychiatric abnormalities. Anti-NMDA-NR1 antibodies are frequently present in high levels in the CSF of the patients with 'Anti-NMDA-receptor encephalitis' due to their intrathecal production. Many patients with 'Anti-NMDA receptor Encephalitis' respond well to several modes of immunotherapy. (3) Anti-NMDA-NR2A/B antibodies are present in a substantial number of patients with Systemic Lupus Erythematosus (SLE) with or without neuropsychiatric problems. The exact percentage of SLE patients having anti-NMDA-NR2A/B antibodies varies in different studies from 14 to 35%, and in one study such antibodies were found in 81% of patients with diffuse 'Neuropshychiatric SLE', and in 44% of patients with focal 'Neuropshychiatric SLE'. Anti-NMDA-NR2A/B antibodies are also present in subpopulations of patients with Epilepsy of several types, Encephalitis of several types (e.g., chronic progressive limbic Encephalitis, Paraneoplastic Encephalitis or Herpes Simplex Virus Encephalitis), Schizophrenia, Mania, Stroke, or Sjorgen syndrome. In some patients, the anti-NMDA-NR2A/B antibodies are present in both the serum and the CSF. Some of the anti-NMDA-NR2A/B antibodies cross-react with dsDNA, while others do not. Some of the anti-NMDA-NR2A/B antibodies associate with neuropsychiatric/cognitive/behavior/mood impairments in SLE patients, while others do not. The anti-NMDA-NR2A/B antibodies can undoubtedly be very pathogenic, since they can kill neurons by activating NMDA receptors and inducing 'Excitotoxicity', damage the brain, cause dramatic decrease of membranal NMDA receptors expressed in hippocampal neurons, and also induce behavioral cognitive impairments in animal models. Yet, the concentration of the anti-NMDA-NR2A/B antibodies seems to determine if they have positive or negative effects on the activity of glutamate receptors and on the survival of neurons. Thus, at low concentration, the anti-NMDA-NR2A/B antibodies were found to be positive modulators of receptor function and increase the size of NMDA receptor-mediated excitatory postsynaptic potentials, whereas at high concentration they are pathogenic as they promote 'Excitotoxcity' through enhanced mitochondrial permeability transition. (4) Anti-mGluR1 antibodies were found thus far in very few patients with Paraneoplastic Cerebellar Ataxia, and in these patients they are produced intrathecally and therefore present in much higher levels in the CSF than in the serum. The anti-mGluR1 antibodies can be very pathogenic in the brain since they can reduce the basal neuronal activity, block the induction of long-term depression of Purkinje cells, and altogether cause cerebellar motor coordination deficits by a combination of rapid effects on both the acute and the plastic responses of Purkinje cells, and by chronic degenerative effects. Strikingly, within 30 min after injection of anti-mGluR1 antibodies into the brain of mice, the mice became ataxic. Anti-mGluR1 antibodies derived from patients with Ataxia also caused disturbance of eye movements in animal models. Immunotherapy can be very effective for some Cerebellar Ataxia patients that have anti-mGluR1 antibodies. (5) Anti-mGluR5 antibodies were found thus far in the serum and CSF of very few patients with Hodgkin lymphoma and Limbic Encephalopathy (Ophelia syndrome). The sera of these patients that contained anti-GluR5 antibodies reacted with the neuropil of the hippocampus and cell surface of live rat hippocampal neurons, and immunoprecipitation from cultured neurons and mass spectrometry demonstrated that the antigen was indeed mGluR5. Taken together, all these evidences show that anti-glutamate receptor antibodies are much more frequent among various neurological diseases than ever realized before, and that they are very detrimental to the nervous system. As such, they call for diagnosis, therapeutic removal or silencing and future studies. What we have learned by now about the broad family of anti-glutamate receptor antibodies is so exciting, novel, unique and important, that it makes all future efforts worthy and essential.
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Affiliation(s)
- Mia Levite
- School of Behavioral Sciences, Academic College of Tel-Aviv-Yafo, Tel Aviv, Israel,
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Stawarski M, Stefaniuk M, Wlodarczyk J. Matrix metalloproteinase-9 involvement in the structural plasticity of dendritic spines. Front Neuroanat 2014; 8:68. [PMID: 25071472 PMCID: PMC4091410 DOI: 10.3389/fnana.2014.00068] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 06/25/2014] [Indexed: 01/01/2023] Open
Abstract
Dendritic spines are the locus for excitatory synaptic transmission in the brain and thus play a major role in neuronal plasticity. The ability to alter synaptic connections includes volumetric changes in dendritic spines that are driven by scaffolds created by the extracellular matrix (ECM). Here, we review the effects of the proteolytic activity of ECM proteases in physiological and pathological structural plasticity. We use matrix metalloproteinase-9 (MMP-9) as an example of an ECM modifier that has recently emerged as a key molecule in regulating the morphology and dysmorphology of dendritic spines that underlie synaptic plasticity and neurological disorders, respectively. We summarize the influence of MMP-9 on the dynamic remodeling of the ECM via the cleavage of extracellular substrates. We discuss its role in the formation, modification, and maintenance of dendritic spines in learning and memory. Finally, we review research that implicates MMP-9 in aberrant synaptic plasticity and spine dysmorphology in neurological disorders, with a focus on morphological abnormalities of dendritic protrusions that are associated with epilepsy.
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Affiliation(s)
- Michal Stawarski
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology Warsaw, Mazowieckie, Poland
| | - Marzena Stefaniuk
- Laboratory of Neurobiology, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology Warsaw, Mzowieckie, Poland
| | - Jakub Wlodarczyk
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology Warsaw, Mazowieckie, Poland
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Pacagnella D, Lopes TM, Morita ME, Yasuda CL, Cappabianco FAM, Bergo F, Balthazar MLF, Coan AC, Cendes F. Memory impairment is not necessarily related to seizure frequency in mesial temporal lobe epilepsy with hippocampal sclerosis. Epilepsia 2014; 55:1197-204. [DOI: 10.1111/epi.12691] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Denise Pacagnella
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
| | - Tatila M. Lopes
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
| | - Marcia E. Morita
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
| | - Clarissa L. Yasuda
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
| | - Fabio A. M. Cappabianco
- Department of Science and Technology; Federal University of Sao Paulo; São José dos Campos SP Brazil
| | - Felipe Bergo
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
| | | | - Ana C. Coan
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
| | - Fernando Cendes
- Department of Neurology; University of Campinas; Campinas Sao Paulo Brazil
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Höller Y, Trinka E. What do temporal lobe epilepsy and progressive mild cognitive impairment have in common? Front Syst Neurosci 2014; 8:58. [PMID: 24795575 PMCID: PMC3997046 DOI: 10.3389/fnsys.2014.00058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 03/25/2014] [Indexed: 12/27/2022] Open
Abstract
Temporal lobe epilepsy (TLE) and mild cognitive impairment (MCI) are both subject to intensive memory research. Memory problems are a core characteristic of both conditions and we wonder if there are analogies which would enrich the two distinct research communities. In this review we focus on memory decline in both conditions, that is, the most feared psychosocial effect. While it is clear that memory decline in MCI is highly likely and would lead to the more severe diagnosis of Alzheimer's disease, it is a debate if TLE is a dementing disease or not. As such, like for MCI, one can differentiate progressive from stable TLE subtypes, mainly depending on the age of onset. Neuroimaging techniques such as volumetric analysis of the hippocampus, entorhinal, and perirhinal cortex show evidence of pathological changes in TLE and are predictive for memory decline in MCI. Several studies emphasize that it is necessary to extend the region of interest—even whole-brain characteristics can be predictive for conversion from MCI to Alzheimer's disease. Electroencephalography is increasingly subject to computational neuroscience, revealing new approaches for analyzing frequency, spatial synchronization, and information content of the signals. These methods together with event-related designs that assess memory functions are highly promising for understanding the mechanisms of memory decline in both TLE and MCI populations. Finally, there is evidence that the potential of such markers for memory decline is far from being exhausted. Similar structural and neurophysiological characteristics are linked to memory decline in TLE and MCI. We raise the hope that interdisciplinary research and cross-talk between fields such as research on epilepsy and dementia, will shed further light on the dementing characteristics of the pathological basis of MCI and TLE and support the development of new memory enhancing treatment strategies.
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Affiliation(s)
- Yvonne Höller
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
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Zhao X, Zhang RX, Tang S, Ren YY, Yang WX, Liu XM, Tang JY. Orexin-A-induced ERK1/2 activation reverses impaired spatial learning and memory in pentylenetetrazol-kindled rats via OX1R-mediated hippocampal neurogenesis. Peptides 2014; 54:140-7. [PMID: 24321199 DOI: 10.1016/j.peptides.2013.11.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 01/07/2023]
Abstract
Epilepsy is characterized by the occurrence of repetitive seizures and can greatly affect a patient's cognition, particularly in terms of learning and memory. Orexin-A is an excitatory neuropeptide produced by the lateral hypothalamus that has been shown to be involved in learning and memory. A reduction in the levels of orexin-A after seizures may underlie the learning and memory impairments induced by epilepsy. Thus, we used pentylenetetrazol (PTZ)-kindled rats to investigate the effects of orexin-A on learning and memory and the involvement of neurogenesis in the dentate gyrus in OX1R-mediated ERK1/2 activation. A Morris water maze test revealed reduced escape latencies, prolonged times in the target quadrant and an increased number of platform crossings in PTZ-kindled rats exposed to orexin-A. These ameliorating effects of orexin-A on spatial learning and memory were attenuated by the intracerebroventricular injection of the OX1R antagonist SB334867 or the ERK1/2 inhibitor U0126. Further studies using bromodeoxyuridine (BrdU) revealed that orexin-A increased the number of BrdU-positive cells, doublecortin (DCX)/BrdU levels and the number of NeuN/BrdU double-positive nuclei in the dentate gyrus of PTZ-kindled rats. However, these effects were inhibited by treatment with SB334867 or U0126. Taken together, these data suggest that orexin-A attenuated the impairment of spatial learning and memory in PTZ-kindled rats and that this attenuation involved neurogenesis in the dentate gyrus via OX1R-mediated ERK1/2 activation.
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Affiliation(s)
- Xuan Zhao
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China
| | - Rui xue Zhang
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China
| | - Shi Tang
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China
| | - Yan yan Ren
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China
| | - Wei xia Yang
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China
| | - Xiao min Liu
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China
| | - Ji you Tang
- Department of Neurology, Qianfoshan Hospital, Shandong University, 16766 Jingshi Road, Jinan, Shandong 250014, PR China.
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62
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Ganor Y, Goldberg-Stern H, Cohen R, Teichberg V, Levite M. Glutamate receptor antibodies directed against AMPA receptors subunit 3 peptide B (GluR3B) can be produced in DBA/2J mice, lower seizure threshold and induce abnormal behavior. Psychoneuroendocrinology 2014; 42:106-17. [PMID: 24636507 DOI: 10.1016/j.psyneuen.2014.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/08/2014] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Anti-GluR3B antibodies (GluR3B Ab's), directed against peptide B/aa372-395 of GluR3 subunit of glutamate/AMPA receptors, are found in ∼35% of epilepsy patients, activate glutamate/AMPA receptors, evoke ion currents, kill neurons and damage the brain. We recently found that GluR3B Ab's also associate with neurological/psychiatric/behavioral abnormalities in epilepsy patients. Here we asked if GluR3B Ab's could be produced in DBA/2J mice, and also modulate seizure threshold and/or cause behavioral/motor impairments in these mice. METHODS DBA/2J mice were immunized with the GluR3B peptide in Complete Freund's Adjuvant (CFA), or with controls: ovalbumin (OVA), CFA, or phosphate-buffer saline (PBS). GluR3B Ab's and OVA Ab's were tested. Seizures were induced in all mice by the chemoconvulsant pentylenetetrazole (PTZ) at three time points, each time with less PTZ to avoid non-specific death. Behavior was examined in Open-Field, RotaRod and Grip tests. RESULTS GluR3B Ab's were produced only in GluR3B-immunized mice, while OVA Ab's were produced only in OVA-immunized mice, showing high Ab's specificity. In GluR3B Ab's negative mice, seizure severity scores and percentages of animals developing generalized seizures declined in response to decreasing PTZ doses. In contrast, both parameters remained unchanged/high in the GluR3B Ab's positive mice, showing that these mice were more susceptible to seizures. The seizure scores associated significantly with the GluR3B Ab's levels. GluR3B Ab's positive mice were also more anxious in Open-Field test, fell faster in RotaRod test, and fell more in Grip test, compared to all the control mice. CONCLUSIONS GluR3B Ab's are produced in DBA/2J mice, facilitate seizures and induce behavioral/motor impairments. This animal model can therefore serve for studying autoimmune epilepsy and abnormal behavior mediated by pathogenic anti-GluR3B Ab's.
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Affiliation(s)
- Yonatan Ganor
- Department of Infection, Immunity and Inflammation, Cochin Institute, INSERM U1016, CNRS UMR8104, Paris Descartes University, Paris, France
| | - Hadassa Goldberg-Stern
- Epilepsy Center, Schneider Children's Medical Center of Israel, Petah Tiqwa, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ran Cohen
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - Vivian Teichberg
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - Mia Levite
- School of Behavioral Sciences, Academic College of TLV Yaffo, Israel.
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63
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Goldberg-Stern H, Ganor Y, Cohen R, Pollak L, Teichberg V, Levite M. Glutamate receptor antibodies directed against AMPA receptors subunit 3 peptide B (GluR3B) associate with some cognitive/psychiatric/behavioral abnormalities in epilepsy patients. Psychoneuroendocrinology 2014; 40:221-31. [PMID: 24485494 DOI: 10.1016/j.psyneuen.2013.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 11/06/2013] [Accepted: 11/06/2013] [Indexed: 11/19/2022]
Abstract
Antibodies (Ab's) to glutamate receptors, directed specifically against AMPA receptors subunit 3 peptide B (i.e. GluR3 amino acids 372-395), named GluR3B Ab's, can by themselves activate GluR3-containing glutamate/AMPA receptors, evoke ion currents via the receptor's ion channel, kill neurons and damage the brain. Herein we first tested 14 consecutive epilepsy patients and 10 healthy controls, and found that 7 (50%) patients had GluR3B Ab's. Second, in 71 other consecutive epilepsy patients (20 generalized epilepsy, 51 partial epilepsy) and 49 controls, we found that 17 (24%) patients had GluR3B Ab's, of which 8 had generalized and 9 partial epilepsy. We then studied 41 epilepsy patients: 21 patients with GluR3B Ab's and 20 without such Ab's (pooled of both tests without biased selection), for possible association of GluR3B Ab's with disease severity and/or neurobehavioral/cognitive comorbidities. Of the 21 patients with GluR3B Ab's, 6 had symptomatic, 7 cryptogenic, and 8 idiopathic epilepsy. Of the 20 patients without GluR3B Ab's, 16 had idiopathic etiology, and 4 nonidiopathic epilepsy. We found that among the 21 patients with GluR3B Ab's, 19 patients (90%) had learning problems, 16 (76%) attention problems, and 15 (71%) psychiatric problems. In contrast, among the 20 patients without GluR3B Ab's, only 6 (30%) had learning problems (p<0.0001), 5 (25%) attention problems (p=0.0017), and 2 (10%) psychiatric problems (p<0.0001). These findings suggest either that neurobehavioral abnormalities occur more frequently in epilepsy patients already having GluR3B Ab's, and may be due to them, or that GluR3B Ab's are more frequent in patients already having neurobehavioral abnormalities.
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Affiliation(s)
- Hadassa Goldberg-Stern
- Epilepsy Service, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Yonatan Ganor
- Department of Infection, Immunity and Inflammation, Cochin Institute, INSERM U1016, CNRS UMR8104, Paris Descartes University, Paris, France
| | - Ran Cohen
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - Lea Pollak
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Neurology, Assaf Harofeh Medical Center, Zriffin, Israel
| | - Vivian Teichberg
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - Mia Levite
- School of Behavioral Sciences, Academic College of Tel Aviv-Yaffo, Tel Aviv, Israel.
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64
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Curia G, Lucchi C, Vinet J, Gualtieri F, Marinelli C, Torsello A, Costantino L, Biagini G. Pathophysiogenesis of mesial temporal lobe epilepsy: is prevention of damage antiepileptogenic? Curr Med Chem 2014; 21:663-88. [PMID: 24251566 PMCID: PMC4101766 DOI: 10.2174/0929867320666131119152201] [Citation(s) in RCA: 152] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/04/2013] [Accepted: 08/29/2013] [Indexed: 12/26/2022]
Abstract
Temporal lobe epilepsy (TLE) is frequently associated with hippocampal sclerosis, possibly caused by a primary brain injury that occurred a long time before the appearance of neurological symptoms. This type of epilepsy is characterized by refractoriness to drug treatment, so to require surgical resection of mesial temporal regions involved in seizure onset. Even this last therapeutic approach may fail in giving relief to patients. Although prevention of hippocampal damage and epileptogenesis after a primary event could be a key innovative approach to TLE, the lack of clear data on the pathophysiological mechanisms leading to TLE does not allow any rational therapy. Here we address the current knowledge on mechanisms supposed to be involved in epileptogenesis, as well as on the possible innovative treatments that may lead to a preventive approach. Besides loss of principal neurons and of specific interneurons, network rearrangement caused by axonal sprouting and neurogenesis are well known phenomena that are integrated by changes in receptor and channel functioning and modifications in other cellular components. In particular, a growing body of evidence from the study of animal models suggests that disruption of vascular and astrocytic components of the blood-brain barrier takes place in injured brain regions such as the hippocampus and piriform cortex. These events may be counteracted by drugs able to prevent damage to the vascular component, as in the case of the growth hormone secretagogue ghrelin and its analogues. A thoroughly investigation on these new pharmacological tools may lead to design effective preventive therapies.
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Affiliation(s)
| | | | | | | | | | | | | | - G Biagini
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Laboratorio di Epilettologia Sperimentale, Universita di Modena e Reggio Emilia, Via Campi, 287, 41125 Modena, Italy.
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65
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Specific impairment of "what-where-when" episodic-like memory in experimental models of temporal lobe epilepsy. J Neurosci 2013; 33:17749-62. [PMID: 24198366 DOI: 10.1523/jneurosci.0957-13.2013] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Episodic memory deficit is a common cognitive disorder in human temporal lobe epilepsy (TLE). However, no animal model of TLE has been shown to specifically replicate this cognitive dysfunction, which has limited its translational appeal. Here, using a task that tests for nonverbal correlates of episodic-like memory in rats, we show that kainate-treated TLE rats exhibit a selective impairment of the "what-where-when" memory while preserving other forms of hippocampal-dependent memories. Assisted by multisite silicon probes, we recorded from the dorsal hippocampus of behaving animals to control for seizure-related factors and to look for electrophysiological signatures of cognitive impairment. Analyses of hippocampal local field potentials showed that both the power of theta rhythm and its coordination across CA1 and the DG-measured as theta coherence and phase locking-were selectively disrupted. This disruption represented a basal condition of the chronic epileptic hippocampus that was linked to different features of memory impairment. Theta power was more correlated with the spatial than with the temporal component of the task, while measures of theta coordination correlated with the temporal component. We conclude that episodic-like memory, as tested in the what-where-when task, is specifically affected in experimental TLE and that the impairment of hippocampal theta activity might be central to this dysfunction.
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66
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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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67
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Richard GR, Titiz A, Tyler A, Holmes GL, Scott RC, Lenck-Santini PP. Speed modulation of hippocampal theta frequency correlates with spatial memory performance. Hippocampus 2013; 23:1269-79. [PMID: 23832676 DOI: 10.1002/hipo.22164] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 11/11/2022]
Abstract
Hippocampal theta rhythm is believed to play a critical role in learning and memory. In animal models of temporal lobe epilepsy (TLE), there is evidence that alterations of hippocampal theta oscillations are involved in the cognitive impairments observed in this model. However, hippocampal theta frequency and amplitude at both the local field potential (LFP) and single unit level are strongly modulated by running speed, suggesting that the integration of locomotor information into memory processes may also be critical for hippocampal processing. Here, we investigate whether hippocampal speed-theta integration influences spatial memory and whether it could account for the memory deficits observed in TLE rats. LFPs were recorded in both Control (CTR) and TLE rats as they were trained in a spatial alternation task. TLE rats required more training sessions to perform the task at CTR levels. Both theta frequency and power were significantly lower in the TLE group. In addition, speed/theta frequency correlation coefficients and regression slopes varied from session to session and were worse in TLE. Importantly, there was a strong relationship between speed/theta frequency parameters and performance. Our analyses reveal that speed/theta frequency correlation with performance cannot merely be explained by the direct influence of speed on behavior. Therefore, variations in the coordination of theta frequency with speed may participate in learning and memory processes. Impairments of this function could explain at least partially memory deficits in epilepsy.
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Affiliation(s)
- Gregory R Richard
- Department of Neurology, Geisel School of Medicine, Hanover, New Hampshire
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68
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Sadek B, Shehab S, Więcek M, Subramanian D, Shafiullah M, Kieć-Kononowicz K, Adem A. Anticonvulsant properties of histamine H3 receptor ligands belonging to N-substituted carbamates of imidazopropanol. Bioorg Med Chem Lett 2013; 23:4886-91. [PMID: 23891186 DOI: 10.1016/j.bmcl.2013.06.075] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/17/2013] [Accepted: 06/27/2013] [Indexed: 12/12/2022]
Abstract
Ligands targeting central histamine H3 receptors (H3Rs) for epilepsy might be a promising therapeutic approach. Therefore, the previously described and structurally strongly related imidazole-based derivatives belonging to carbamate class with high H3R in vitro affinity, in-vivo antagonist potency, and H3R selectivity profile were investigated on their anticonvulsant activity in maximal electroshock (MES)-induced and pentylenetetrazole (PTZ)-kindled seizure models in Wistar rats. The effects of systemic injection of H3R ligands 1-13 on MES-induced and PTZ-kindled seizures were screened and evaluated against the reference antiepileptic drug (AED) Phenytoin (PHT) and the standard histamine H3R inverse agonist/antagonist Thioperamide (THP) to determine their potential as new antiepileptic drugs. Following administration of the H3R ligands 1-13 (5, 10 and 15 mg/kg, ip) there was a significant dose dependent reduction in MES-induced seizure duration. The protective action observed for the pentenyl carbamate derivative 4, the most protective H3R ligand among 1-13, was significantly higher (P <0.05) than that of standard H3R antagonist THP, and was reversed when rats were pretreated with the selective H3R agonist R-(α)-methyl-histamine (RAMH) (10mg/kg), or with the CNS penetrant H1R antagonist Pyrilamine (PYR) (10mg/kg). In addition, subeffective dose of H3R ligand 4 (5mg/kg, ip) significantly potentiated the protective action in rats pretreated with PHT (5mg/kg, ip), a dose without appreciable protective effect when given alone. In contrast, pretreatment with H3R ligand 4 (10mg/kg ip) failed to modify PTZ-kindled convulsion, whereas the reference drug PHT was found to fully protect PTZ-induced seizure. These results indicate that some of the investigated imidazole-based H3R ligands 1-13 may be of future therapeutic value in epilepsy.
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Affiliation(s)
- Bassem Sadek
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, PO Box 17666, United Arab Emirates.
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69
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Kleen JK, Scott RC, Holmes GL, Roberts DW, Rundle MM, Testorf M, Lenck-Santini PP, Jobst BC. Hippocampal interictal epileptiform activity disrupts cognition in humans. Neurology 2013; 81:18-24. [PMID: 23685931 DOI: 10.1212/wnl.0b013e318297ee50] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE We investigated whether interictal epileptiform discharges (IED) in the human hippocampus are related to impairment of specific memory processes, and which characteristics of hippocampal IED are most associated with memory dysfunction. METHODS Ten patients had depth electrodes implanted into their hippocampi for preoperative seizure localization. EEG was recorded during 2,070 total trials of a short-term memory task, with memory processing categorized into encoding, maintenance, and retrieval. The influence of hippocampal IED on these processes was analyzed and adjusted to account for individual differences between patients. RESULTS Hippocampal IED occurring in the memory retrieval period decreased the likelihood of a correct response when they were contralateral to the seizure focus (p < 0.05) or bilateral (p < 0.001). Bilateral IED during the memory maintenance period had a similar effect (p < 0.01), particularly with spike-wave complexes of longer duration (p < 0.01). IED during encoding had no effect, and reaction time was also unaffected by IED. CONCLUSIONS Hippocampal IED in humans may disrupt memory maintenance and retrieval, but not encoding. The particular effects of bilateral IED and those contralateral to the seizure focus may relate to neural compensation in the more functional hemisphere. This study provides biological validity to animal models in the study of IED-related transient cognitive impairment. Moreover, it strengthens the argument that IED may contribute to cognitive impairment in epilepsy depending upon when and where they occur.
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Affiliation(s)
- Jonathan K Kleen
- Department of Neurology, Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
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70
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Miltiadous P, Kouroupi G, Stamatakis A, Koutsoudaki PN, Matsas R, Stylianopoulou F. Subventricular zone-derived neural stem cell grafts protect against hippocampal degeneration and restore cognitive function in the mouse following intrahippocampal kainic acid administration. Stem Cells Transl Med 2013; 2:185-98. [PMID: 23417642 DOI: 10.5966/sctm.2012-0074] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is a major neurological disease, often associated with cognitive decline. Since approximately 30% of patients are resistant to antiepileptic drugs, TLE is being considered as a possible clinical target for alternative stem cell-based therapies. Given that insulin-like growth factor I (IGF-I) is neuroprotective following a number of experimental insults to the nervous system, we investigated the therapeutic potential of neural stem/precursor cells (NSCs) transduced, or not, with a lentiviral vector for overexpression of IGF-I after transplantation in a mouse model of kainic acid (KA)-induced hippocampal degeneration, which represents an animal model of TLE. Exposure of mice to the Morris water maze task revealed that unilateral intrahippocampal NSC transplantation significantly prevented the KA-induced cognitive decline. Moreover, NSC grafting protected against neurodegeneration at the cellular level, reduced astrogliosis, and maintained endogenous granule cell proliferation at normal levels. In some cases, as in the reduction of hippocampal cell loss and the reversal of the characteristic KA-induced granule cell dispersal, the beneficial effects of transplanted NSCs were manifested earlier and were more pronounced when these were transduced to express IGF-I. However, differences became less pronounced by 2 months postgrafting, since similar amounts of IGF-I were detected in the hippocampi of both groups of mice that received cell transplants. Grafted NSCs survived, migrated, and differentiated into neurons-including glutamatergic cells-and not glia, in the host hippocampus. Our results demonstrate that transplantation of IGF-I producing NSCs is neuroprotective and restores cognitive function following KA-induced hippocampal degeneration.
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MESH Headings
- Animals
- Astrocytes/metabolism
- Astrocytes/pathology
- Behavior, Animal
- Cell Movement
- Cell Proliferation
- Cell Survival
- Cognition
- Disease Models, Animal
- Epilepsy, Temporal Lobe/chemically induced
- Epilepsy, Temporal Lobe/genetics
- Epilepsy, Temporal Lobe/metabolism
- Epilepsy, Temporal Lobe/pathology
- Epilepsy, Temporal Lobe/physiopathology
- Epilepsy, Temporal Lobe/psychology
- Epilepsy, Temporal Lobe/therapy
- Genetic Therapy/methods
- Genetic Vectors
- Glutamic Acid/metabolism
- Green Fluorescent Proteins/biosynthesis
- Green Fluorescent Proteins/genetics
- Hippocampus/metabolism
- Hippocampus/pathology
- Hippocampus/physiopathology
- Hippocampus/surgery
- Insulin-Like Growth Factor I/biosynthesis
- Insulin-Like Growth Factor I/genetics
- Kainic Acid
- Lentivirus/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Nerve Degeneration
- Neural Stem Cells/metabolism
- Neural Stem Cells/transplantation
- Neurogenesis
- Neurons/metabolism
- Neurons/pathology
- Spheroids, Cellular
- Time Factors
- Transduction, Genetic
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71
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Inada C, Thi Le X, Tsuneyama K, Fujiwara H, Miyata T, Matsumoto K. Endogenous acetylcholine rescues NMDA-induced long-lasting hippocampal cell damage via stimulation of muscarinic M1 receptors: Elucidation using organic hippocampal slice cultures. Eur J Pharmacol 2013; 699:150-9. [DOI: 10.1016/j.ejphar.2012.11.061] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/20/2012] [Accepted: 11/28/2012] [Indexed: 11/16/2022]
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72
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Rzezak P, Guimarães CA, Fuentes D, Guerreiro MM, Valente KD. Memory in children with temporal lobe epilepsy is at least partially explained by executive dysfunction. Epilepsy Behav 2012; 25:577-84. [PMID: 23159382 DOI: 10.1016/j.yebeh.2012.09.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/24/2012] [Accepted: 09/29/2012] [Indexed: 11/24/2022]
Abstract
An association between memory and executive dysfunction (ED) has been demonstrated in patients with mixed neurological disorders. We aimed to investigate the impact of ED in memory tasks of children with temporal lobe epilepsy (TLE). We evaluated 36 children with TLE and 28 controls with tests for memory, learning, attention, mental flexibility, and mental tracking. Data analysis was composed of comparison between patients and controls in memory and executive function; correlation between memory and executive function tests; and comparison between patients with mild and severe ED in memory tests. Children with TLE had worse performance in focused attention, immediate and delayed recall, phonological memory, mental tracking, planning, and abstraction. Planning, abstraction, and mental tracking were correlated with visual and verbal memory. Children with severe ED had worse performance in verbal and visual memory and learning tests. This study showed that ED was related to memory performance in children with TLE.
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Affiliation(s)
- Patricia Rzezak
- LIM-21, Laboratory for Medical Research 21-Neuroimaging Laboratory, Department of Psychiatry, University of São Paulo, São Paulo, Brazil.
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73
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Andres-Mach M, Fike JR, Łuszczki JJ. Neurogenesis in the epileptic brain: a brief overview from temporal lobe epilepsy. Pharmacol Rep 2012; 63:1316-23. [PMID: 22358080 DOI: 10.1016/s1734-1140(11)70696-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 08/02/2011] [Indexed: 01/03/2023]
Abstract
Dentate granule cell neurogenesis persists throughout life in the hippocampus of mammals. Alterations in this process occur in many neurological diseases, including epilepsy. Among the different types of epilepsy, the most frequent is temporal lobe epilepsy (TLE). Therefore, a number of laboratory studies use animal models of TLE to observe the fate of neuronal cells after seizures. Hippocampal neurogenesis is very sensitive to physiological and pathological stimuli. Seizures, as pathological stimuli, alter both the extent and the pattern of neurogenesis, which is associated with cognitive function. Various alterations in neurogenesis are observed depending on the amount of time that has elapsed after the seizures. In acute seizures, neurogenesis generally increases, whereas in chronic epilepsy, neurogenesis decreases. Moreover, several methods currently used for the treatment of brain disorders such as TLE can also have significant impacts on cognitive functions. This review is focused on the recent findings regarding neurogenesis in animal models of TLE.
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Affiliation(s)
- Marta Andres-Mach
- Isobolographic Analysis Laboratory, Institute of Agricultural Medicine, Lublin, Jaczewskiego 2, PL 20-090 Poland.
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74
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Holmes M, Folley BS, Sonmezturk HH, Gore JC, Kang H, Abou-Khalil B, Morgan VL. Resting state functional connectivity of the hippocampus associated with neurocognitive function in left temporal lobe epilepsy. Hum Brain Mapp 2012; 35:735-44. [PMID: 23124719 DOI: 10.1002/hbm.22210] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 06/26/2012] [Accepted: 09/11/2012] [Indexed: 11/11/2022] Open
Abstract
The majority of patients with temporal lobe epilepsy (TLE) experience disturbances of episodic memory from structural damage or dysfunction of the hippocampus. The objective of this study was to use functional Magnetic Resonance Imaging (fMRI) to identify regions where resting state connectivity to the left hippocampus (LH) is correlated with neuropsychological measures of verbal memory retention in TLE patients. Eleven left TLE (LTLE) patients and 15 control subjects participated in resting state fMRI scans. All LTLE patients underwent neuropsychological testing. Resting state functional connectivity maps to the LH were calculated for each patient, and subsequently used in a multiple regression analysis with verbal memory retention scores as a covariate. The analysis identified brain regions whose connectivity to the LH was linearly related to memory retention scores across the group of patients. In LTLE patients, right sided (contralateral) clusters in the precuneus and inferior parietal lobule (IPL) exhibited increased connectivity to the LH with increased memory retention score; left sided (ipsilateral) regions in the precuneus and IPL showed increased connectivity to the LH with decreased retention score. Patients with high memory retention scores had greater connectivity between the LH-right parietal clusters than between the LH-left parietal clusters; in contrast, control subjects had significantly and consistently greater LH-left hemisphere than LH-right hemisphere connectivity. Our results suggest that increased connectivity in contralateral hippocampal functional pathways within the episodic verbal memory network represents a strengthening of alternative pathways in LTLE patients with strong verbal memory retention abilities.
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Affiliation(s)
- Martha Holmes
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee; Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee
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75
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Kurzbuch K, Pauli E, Gaál L, Kerling F, Kasper BS, Stefan H, Hamer H, Graf W. Computerized cognitive testing in epilepsy (CCTE): a new method for cognitive screening. Seizure 2012; 22:424-32. [PMID: 22999215 DOI: 10.1016/j.seizure.2012.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 08/29/2012] [Accepted: 08/29/2012] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Optimized therapy in epilepsy should include individual care for cognitive functions. Here we introduce a computerized screening instrument, called "Computerized Cognitive Testing in Epilepsy" (CCTE), which allows for time-efficient repetitive assessment of the patient's cognitive profile regarding the domains of memory and attention, which are frequently impaired due to side effects of antiepileptic medication. METHODS The CCTE battery takes 30min and covers tasks of verbal and figural memory, cognitive speed, attention and working memory. The patient's results are displayed immediately in comparison to age-related normative data. For evaluation of psychometrics and clinical correlations, data from patients of a tertiary referral epilepsy center (n=240) and healthy subjects (n=83) were explored. RESULTS CCTE subtests show good reliability and concurrent validity compared to standard neuropsychological tests (p<0.01). Adverse cognitive effects of antiepileptic medication can be detected (p<0.05), e.g. significant negative effects of increasing drug load. Specific epilepsy subgroups, e.g. focal versus primary generalized epilepsy or right versus left mesial temporal lobe epilepsy, showed different CCTE profiles. CONCLUSION CCTE appears valuable for early detection of individual cognitive alterations related to medication. In addition, it displays interesting differences between epilepsy syndromes. The CCTE battery provides a standardized, time- and personnel-efficient assessment of cognitive functions open to a large number of patients and applicable for clinical and scientific use in epilepsy.
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Affiliation(s)
- Katrin Kurzbuch
- Epilepsy Center, Department of Neurology, University of Erlangen-Nürnberg, Germany.
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76
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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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77
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Gauffin H, Flensner G, Landtblom AM. Living with epilepsy accompanied by cognitive difficulties: young adults' experiences. Epilepsy Behav 2011; 22:750-8. [PMID: 22019020 DOI: 10.1016/j.yebeh.2011.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 09/05/2011] [Accepted: 09/06/2011] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Epilepsy can sometimes be followed by memory impairment. This can result from the underlying cause of epilepsy or from recurrent seizures, or can be a side effect of antiepileptic drugs or a symptom of another disease such as depression. The aim of the study described here was to explore the experience of living with epilepsy and subjective cognitive decline. METHOD To better understand the deeper meaning of the phenomenon, a qualitative design was chosen. Fourteen adults aged 18-35 took part in focus group interviews. The participants were divided into four groups, two groups of women and two groups of men, and the interviews were conducted according to a semistructured protocol. Transcripts were analyzed in accordance with the content analysis guidelines. RESULTS Four themes emerged: "affecting the whole person," "influencing daily life," "affecting relationships," and "meeting ignorance in society." CONCLUSIONS Cognitive decline has a heavy impact on young adults with intractable epilepsy. In contrast to seizures, the cognitive decline is persistent. The themes reflected different hardships faced by the participants. The consequences of living with epilepsy and cognitive impairment concerned education, employment, social life, self-esteem, and hope for the future. The participants were already using strategies to cope with their cognitive decline, but may benefit from help in developing new strategies to better adjust to their memory problems. Development of more educational programs for both people with epilepsy and their relatives could improve their difficult situations. With help, people can learn to adjust their goals in life and live a fulfilling life despite the disease.
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Affiliation(s)
- Helena Gauffin
- Division of Neurology, Medical Faculty/IKE, Linköping University, Sweden.
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78
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Abstract
With the rapid rise in our knowledge about the structural and functional properties of neuronal microcircuits and the exponentially increasing power of computers, it has become possible to closely integrate experimental findings with large-scale, anatomically and biophysically realistic computational simulations of control and epileptic neuronal networks with unprecedented precision and predictive power. In this paper, we discuss the biological basis of model development, and outline specific applications, including exciting new computational and experimental results concerning the roles of aberrant hyperconnected hub-like neurons in seizures.
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Affiliation(s)
- Marianne Case
- Anatomy & Neurobiology, University of California-Irvine, CA 92697, USA.
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79
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Hippocampal-dependent spatial memory in the water maze is preserved in an experimental model of temporal lobe epilepsy in rats. PLoS One 2011; 6:e22372. [PMID: 21829459 PMCID: PMC3144225 DOI: 10.1371/journal.pone.0022372] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 06/27/2011] [Indexed: 02/06/2023] Open
Abstract
Cognitive impairment is a major concern in temporal lobe epilepsy (TLE). While different experimental models have been used to characterize TLE-related cognitive deficits, little is known on whether a particular deficit is more associated with the underlying brain injuries than with the epileptic condition per se. Here, we look at the relationship between the pattern of brain damage and spatial memory deficits in two chronic models of TLE (lithium-pilocarpine, LIP and kainic acid, KA) from two different rat strains (Wistar and Sprague-Dawley) using the Morris water maze and the elevated plus maze in combination with MRI imaging and post-morten neuronal immunostaining. We found fundamental differences between LIP- and KA-treated epileptic rats regarding spatial memory deficits and anxiety. LIP-treated animals from both strains showed significant impairment in the acquisition and retention of spatial memory, and were unable to learn a cued version of the task. In contrast, KA-treated rats were differently affected. Sprague-Dawley KA-treated rats learned less efficiently than Wistar KA-treated animals, which performed similar to control rats in the acquisition and in a probe trial testing for spatial memory. Different anxiety levels and the extension of brain lesions affecting the hippocampus and the amydgala concur with spatial memory deficits observed in epileptic rats. Hence, our results suggest that hippocampal-dependent spatial memory is not necessarily affected in TLE and that comorbidity between spatial deficits and anxiety is more related with the underlying brain lesions than with the epileptic condition per se.
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80
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Helmstaedter C, Petzold I, Bien CG. The cognitive consequence of resecting nonlesional tissues in epilepsy surgery--results from MRI- and histopathology-negative patients with temporal lobe epilepsy. Epilepsia 2011; 52:1402-8. [PMID: 21740419 DOI: 10.1111/j.1528-1167.2011.03157.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Because more selective and individual versus extended standard surgery in the treatment of epilepsy appears to result in similar seizure outcomes, the issue of sparing nonlesional and hypothetically still-functioning tissues has become a central topic in epilepsy surgery. Within this framework we hypothesized that surgery in magnetic resonance imaging (MRI)- and histopathologically negative patients with temporal lobe epilepsy (TLE) may serve as a proof of principle about the negative cognitive consequences of resecting nonlesional tissue. METHODS Verbal and figural memory outcomes after temporal lobe surgery in 15 MRI- and histopathologically negative patients (MRH-) were compared to those obtained in 15 MRI- and histopathologically positive patients (MRH+). In the MRH- group, 53% were male, 66% were resected on the left side, 13% underwent selective amygdalohippocampectomy, and 20% became seizure-free. MRH+ patients were selected from >1,000 TLE patients, and provided matched pairs in regard to chronological age, sex, IQ, attention performance, onset of epilepsy, side and type of surgery, age at surgery, and seizure outcome. Individual and combined standardized scores for verbal/figural memory were evaluated. KEY FINDINGS Preoperatively, memory was significantly better and less frequently impaired in MRH- as opposed to MRH+ patients. Postoperatively, memory losses in MRH- were more severe as opposed to MRH+ patients who did not change, on average. Losses in individual test parameters were seen in between 27% and 80% in MRH- patients as compared to between 13% and 47% in MRH+ patients. After surgery, outcomes for both groups were at comparably poor performance levels. SIGNIFICANCE Preoperative group differences in memory and the finding that, after surgery, both groups had comparably poor performance levels indicate a major relevance of morphologic structural lesions for memory impairment in TLE. The findings in particular confirm the negative impact of the resection of nonlesional functional tissue for cognitive surgical outcome. Absence of MRI lesion and unimpaired memory appear as significant risk factors for postoperative memory loss in temporal lobe surgery.
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IGF-I ameliorates hippocampal neurodegeneration and protects against cognitive deficits in an animal model of temporal lobe epilepsy. Exp Neurol 2011; 231:223-35. [PMID: 21756906 DOI: 10.1016/j.expneurol.2011.06.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 05/11/2011] [Accepted: 06/23/2011] [Indexed: 12/26/2022]
Abstract
Epilepsy is a major neurological disease, and patients often show spatial memory deficits. Thus, there is a need of effective new therapeutic approaches. IGF-I has been shown to be neuroprotective following a number of experimental insults to the nervous system, and in a variety of animal models of neurodegenerative diseases. In the present work, we investigated the possible neuroprotective effects of IGF-I following unilateral intrahippocampal administration of kainic acid (KA), an animal model of temporal lobe epilepsy (TLE). KA induced cell death, as shown by FluoroJade B, and extensive cell loss in both the ipsilateral and contralateral CA3 and CA4 areas, as well as granule cell dispersal in the DG, as revealed by Cresyl violet staining. KA also resulted in intense astrogliosis and microgliosis, as assessed by the number of GFAP and CD11b immunopositive cells, respectively, and increased hippocampal neurogenesis. Exposure to the Morris Water Maze task revealed that mice injected with KA were deficient in spatial learning and both short- and long-term memories, when tested in a larger diameter pool, which requires the use of allocentric strategies. When tested in a smaller pool, only long-term memory was impaired. Administration of IGF-I decreased seizure severity, hippocampal neurogenesis, and protected against neurodegeneration at the cellular level as assessed by FluoroJade B and Cresyl violet staining, as well as the number of GFAP and CD11b immunopositive cells. Furthermore, IGF-I abolished the cognitive deficits. Our results support that IGF-I could have a possible therapeutic potential in TLE.
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82
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Medial temporal theta/alpha power enhancement precedes successful memory encoding: evidence based on intracranial EEG. J Neurosci 2011; 31:5392-7. [PMID: 21471374 DOI: 10.1523/jneurosci.3668-10.2011] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Not only poststimulus, but also prestimulus neural activity has been shown to be predictive for later successful memory encoding. However, it is still not clear which medial temporal lobe processes precede effective memory formation. Here, our aim was to investigate whether such prestimulus markers for successful memory encoding can be specified based on intracranial recordings directly from the hippocampus and rhinal cortex. For this purpose, we analyzed subsequent memory effects during a continuous word recognition paradigm in 31 presurgical epilepsy patients. We found that rhinal and hippocampal theta and successive alpha power enhancement before word presentation predicted successful memory encoding. Previous studies suggest that stimulus-triggered hippocampal theta activity is particularly related to memory retrieval and activation of a mnemonic context, whereas the alpha rhythm reflects inhibitory top-down control of task processing and executive functioning. In line with these suggestions, we propose that the observed medial temporal theta and alpha power increases before stimulus presentation reflect activation of contextual information and inhibitory top-down control processes preparing for stimulus-triggered memory processing.
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83
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Vlooswijk MCG, Jansen JFA, Jeukens CRLPN, Majoie HJM, Hofman PAM, de Krom MCTFM, Aldenkamp AP, Backes WH. Memory processes and prefrontal network dysfunction in cryptogenic epilepsy. Epilepsia 2011; 52:1467-75. [PMID: 21635235 DOI: 10.1111/j.1528-1167.2011.03108.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Impaired memory performance is the most frequently reported cognitive problem in patients with chronic epilepsy. To examine memory deficits many studies have focused on the role of the mesiotemporal lobe, mostly with hippocampal abnormalities. However, the role of the prefrontal brain remains unresolved. To investigate the neuronal correlates of working memory dysfunction in patients without structural lesions, a combined study of neurocognitive assessment, hippocampal and cerebral volumetry, and functional magnetic resonance imaging of temporal and frontal memory networks was performed. METHODS Thirty-six patients with cryptogenic localization-related epilepsy and 21 healthy controls underwent neuropsychological assessment of intelligence (IQ) and memory. On T(1) -weighted images obtained by 3-Tesla magnetic resonance imaging (MRI), volumetry of the hippocampi and the cerebrum was performed. Functional MRI (fMRI) was performed with a novel picture encoding and Sternberg paradigm that activated different memory-mediating brain regions. Functional connectivity analysis comprised cross-correlation of signal time-series of the most strongly activated regions involved in working memory function. KEY FINDINGS Patients with epilepsy displayed lower IQ values; impaired transient aspects of information processing, as indicated by lower scores on the digit-symbol substitution test (DSST); and decreased short-term memory performance relative to healthy controls, as measured with the Wechsler Adult Intelligence Scale subtests for working memory, and word and figure recognition. This could not be related to any hippocampal volume changes. No group differences were found regarding volumetry or fMRI-derived functional activation. In the Sternberg paradigm, a network involving the anterior cingulate and the middle and inferior frontal gyrus was activated. A reduced strength of four connections in this prefrontal network was associated with the DSST and word recognition performance in the patient group. SIGNIFICANCE Deficits in the processes involved in transient working memory, and to a lesser extent in short-term memory, in patients with localization-related epilepsy of both temporal and extratemporal origin cannot be attributed to hippocampal atrophy or function only, but are also related to reduced functional connectivity in the prefrontal brain. Because patients with symptomatic lesions or mesiotemporal sclerosis were excluded from this study, the results cannot be explained by structural lesions. Therefore, the current findings highlight the influence of epilepsy on the prefrontal network integrity as a possible underlying problem of memory impairment.
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Affiliation(s)
- Marielle C G Vlooswijk
- Department of Neurology, Maastricht University Medical Centre, Maastricht, The Netherlands.
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84
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Pierce JP, McCloskey DP, Scharfman HE. Morphometry of hilar ectopic granule cells in the rat. J Comp Neurol 2011; 519:1196-218. [PMID: 21344409 DOI: 10.1002/cne.22568] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Granule cell (GC) neurogenesis in the dentate gyrus (DG) does not always proceed normally. After severe seizures (e.g., status epilepticus [SE]) and some other conditions, newborn GCs appear in the hilus. Hilar ectopic GCs (EGCs) can potentially provide insight into the effects of abnormal location and seizures on GC development. Additionally, hilar EGCs that develop after SE may contribute to epileptogenesis and cognitive impairments that follow SE. Thus, it is critical to understand how EGCs differ from normal GCs. Relatively little morphometric information is available on EGCs, especially those restricted to the hilus. This study quantitatively analyzed the structural morphology of hilar EGCs from adult male rats several months after pilocarpine-induced SE, when they are considered to have chronic epilepsy. Hilar EGCs were physiologically identified in slices, intracellularly labeled, processed for light microscopic reconstruction, and compared to GC layer GCs, from both the same post-SE tissue and the NeuroMorpho database (normal GCs). Consistently, hilar EGC and GC layer GCs had similar dendritic lengths and field sizes, and identifiable apical dendrites. However, hilar EGC dendrites were topologically more complex, with more branch points and tortuous dendritic paths. Three-dimensional analysis revealed that, remarkably, hilar EGC dendrites often extended along the longitudinal DG axis, suggesting increased capacity for septotemporal integration. Axonal reconstruction demonstrated that hilar EGCs contributed to mossy fiber sprouting. This combination of preserved and aberrant morphological features, potentially supporting convergent afferent input to EGCs and broad, divergent efferent output, could help explain why the hilar EGC population could impair DG function.
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Affiliation(s)
- Joseph P Pierce
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York 10065, USA.
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85
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Zamarian L, Trinka E, Bonatti E, Kuchukhidze G, Bodner T, Benke T, Koppelstaetter F, Delazer M. Executive functions in chronic mesial temporal lobe epilepsy. EPILEPSY RESEARCH AND TREATMENT 2011; 2011:596174. [PMID: 22937233 PMCID: PMC3428608 DOI: 10.1155/2011/596174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 12/06/2010] [Accepted: 01/11/2011] [Indexed: 12/02/2022]
Abstract
There is no consensus as to whether mesial temporal lobe epilepsy (MTLE) leads to executive function deficits. In this study, we adopted an extensive neuropsychological test battery and assessed different executive functions in chronic, unilateral MTLE. Performance of MTLE patients was compared with that of healthy peers and with normative data. Several MTLE patients had scores below cut-off or below the 10th percentile of normative data. Scores of the whole patient group were overall in the average range of normative data. Relative to controls, MTLE patients performed poorly in tests of working memory, cognitive flexibility, categorical verbal fluency, set-shifting, categorization, and planning. These findings raise an important methodological issue as they suggest that executive function deficits in chronic MTLE may be individually variable and that their assessment should include different tests. Deficits in chronic MTLE are not limited to temporal lobe functions, such as memory, but may extend to extra temporal cognitive domains, such as executive functions.
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Affiliation(s)
- Laura Zamarian
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Eugen Trinka
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
- Department of Neurology, Christian Doppler Clinic, Paracelsus Medical University, Ignaz Herrer Strasse 79, 5020 Salzburg, Austria
| | - Elisabeth Bonatti
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Giorgi Kuchukhidze
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Thomas Bodner
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Thomas Benke
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Florian Koppelstaetter
- Clinical Department of Radiology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Margarete Delazer
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
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Fliessbach K, Witt JA, Packheiser J, von Lehe M, Elger CE, Helmstaedter C. Depth-of-processing effects on memory encoding after selective amygdalohippocampectomy. Behav Brain Res 2011; 216:402-7. [DOI: 10.1016/j.bbr.2010.08.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/16/2010] [Accepted: 08/18/2010] [Indexed: 10/19/2022]
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87
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Gu P, Li Y, Shang Y, Hou Y, Zhao S. Proliferation changes in dentate gyrus of hippocampus during the first week following kainic acid-induced seizures. YAKUGAKU ZASSHI 2010; 130:1751-4. [PMID: 21139403 DOI: 10.1248/yakushi.130.1751] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long-term neuroplastic changes in dentate gyrus (DG) have been reported after seizure induction and were shown to contribute to epitogenesis of epilepsy. These changes include increased number of newborn granule cells, sprouted mossy fibers, granule cell layer dispersion, etc. The aim of current study is to determine the acute progression of neuroplastic changes involved newly generated granule cells after kainic acid (KA)-induced seizures. Doublecortion (DCX) analysis was used to examine the newly generated granule cells morphology 1-7 days after seizure induction. Quantitative analysis of DCX-labeled cells at different times shows that there are some rapid changes in the dentate gyrus. At day 7 epileptical mice induced an increase of the number of DCX-labeled cells in DG. At days 3 and 7 after epilepsy induction, the percentage of DCX-labeled cells per DG were significantly increased. These results show that seizures are capable to increase the number of new granule cell within a short time for function activation in post-seizure period. Therefore, the rapid changes in the DG might be having a potential for hippocampus neuroplastic function.
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Affiliation(s)
- Peifei Gu
- Centre of Clinical Pharmacology, Northeast Pharmaceutical Science and Technology Co., Ltd., Shenyang, P. R. China.
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88
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The effects of atorvastatin on memory deficit and seizure susceptibility in pentylentetrazole-kindled rats. Epilepsy Behav 2010; 19:284-9. [PMID: 20888302 DOI: 10.1016/j.yebeh.2010.07.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 07/21/2010] [Accepted: 07/26/2010] [Indexed: 11/22/2022]
Abstract
Deficits in memory function have been observed in pentylentetrazole (PTZ)-kindled rats. In the present study we examined the effects of atorvastatin ((3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitor) on PTZ kindling and related memory deficits in rats trained with the passive avoidance test. Subconvulsive PTZ doses rendered a gradual increase in seizure activity. PTZ kindling caused long-term memory to deteriorate. Atorvastatin per se and in PTZ-kindled rats improved learning and memory functions. It also prolonged latency (time to appearance of spike potentials) and diminished the amplitude and frequency of spike potentials, which indicate epileptic discharges. These novel findings suggest that the favorable effect of the atorvastatin on memory deficits provoked by PTZ kindling might be of clinical utility.
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Vlooswijk MC, Jansen JF, de Krom MC, Majoie HM, Hofman PA, Backes WH, Aldenkamp AP. Functional MRI in chronic epilepsy: associations with cognitive impairment. Lancet Neurol 2010; 9:1018-27. [PMID: 20708970 DOI: 10.1016/s1474-4422(10)70180-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chronic epilepsy is frequently accompanied by serious cognitive side-effects. Clinical factors are important, but cannot account entirely for this cognitive comorbidity. Therefore, research is focusing on the underlying cerebral mechanisms to understand the development of cognitive dysfunction. In the past two decades, functional MRI techniques have been applied extensively to the study of cognitive impairment in chronic epilepsy. However, because of wide variation in study designs, analysis methods, and data presentation, interpretation of these studies has become increasingly difficult for clinicians. In patients with localisation-related epilepsy, whether findings of functional MRI represent the underlying neuronal substrate for cognitive decline remains a subject of debate.
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Affiliation(s)
- Marielle Cg Vlooswijk
- Department of Neurology, Maastricht University Medical Centre, Maastricht, Netherlands
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90
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Tudesco IDSS, Vaz LJ, Mantoan MAS, Belzunces E, Noffs MH, Caboclo LOSF, Yacubian EMT, Sakamoto AC, Bueno OFA. Assessment of working memory in patients with mesial temporal lobe epilepsy associated with unilateral hippocampal sclerosis. Epilepsy Behav 2010; 18:223-8. [PMID: 20547107 DOI: 10.1016/j.yebeh.2010.04.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 04/17/2010] [Accepted: 04/20/2010] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The aim of the present study was to investigate whether working memory is impaired in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), a controversial and largely unexplored matter. METHODS Twenty subjects with left MTLE-HS, 19 with right MTLE-HS, and 21 control right-handed subjects underwent neuropsychological assessment of episodic and semantic memory, executive functions, and specific working memory components. RESULTS Left and right epileptogenic foci resulted in impairment of verbal and nonverbal episodic memory (verbal memory deficit greater in left MTLE-HS than in right MTLE-HS). In addition, patients with left MTLE-HS were impaired in learning paired associates, verbal fluency, and Trail Making. No differences were seen in the tests carried out to evaluate the working memory components (except visuospatial short-term memory in right MTLE-HS). CONCLUSION In this study we did not detect reliable working memory impairment in patients with MTLE-HS with either a left or right focus in most tasks considered as tests of working memory components.
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91
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Abstract
It is well known that neuropsychological impairment can be associated with chronic epilepsy. This review suggests that a broad lifespan perspective of cognition in epilepsy should include consideration of: a) neurobiological factors that antedate the first seizure and influence cognition, b) epilepsy-related factors that influence brain growth and cognitive development after epilepsy is diagnosed and treated, c) clinical epilepsy and other risk factors associated with poor cognitive prognosis in the context of chronic pharmacoresistant epilepsy, and d) the modifiable and non-modifiable risk factors that influence cognitive aging in the general population.
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Affiliation(s)
- Bruce Hermann
- Department of Neurology, University ofWisconsin School ofMedicine and PublicHealth, Madison, Wisconsin, USA.
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Liu X, Wen F, Yang J, Chen L, Wei YQ. A review of current applications of mass spectrometry for neuroproteomics in epilepsy. MASS SPECTROMETRY REVIEWS 2010; 29:197-246. [PMID: 19598206 DOI: 10.1002/mas.20243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The brain is unquestionably the most fascinating organ, and the hippocampus is crucial in memory storage and retrieval and plays an important role in stress response. In temporal lobe epilepsy (TLE), the seizure origin typically involves the hippocampal formation. Despite tremendous progress, current knowledge falls short of being able to explain its function. An emerging approach toward an improved understanding of the complex molecular mechanisms that underlie functions of the brain and hippocampus is neuroproteomics. Mass spectrometry has been widely used to analyze biological samples, and has evolved into an indispensable tool for proteomics research. In this review, we present a general overview of the application of mass spectrometry in proteomics, summarize neuroproteomics and systems biology-based discovery of protein biomarkers for epilepsy, discuss the methodology needed to explore the epileptic hippocampus proteome, and also focus on applications of ingenuity pathway analysis (IPA) in disease research. This neuroproteomics survey presents a framework for large-scale protein research in epilepsy that can be applied for immediate epileptic biomarker discovery and the far-reaching systems biology understanding of the protein regulatory networks. Ultimately, knowledge attained through neuroproteomics could lead to clinical diagnostics and therapeutics to lessen the burden of epilepsy on society.
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Affiliation(s)
- Xinyu Liu
- National Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
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Kleen JK, Scott RC, Holmes GL, Lenck-Santini PP. Hippocampal interictal spikes disrupt cognition in rats. Ann Neurol 2010; 67:250-7. [PMID: 20225290 DOI: 10.1002/ana.21896] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Cognitive impairment is common in epilepsy, particularly in memory function. Interictal spikes (IISs) are thought to disrupt cognition, but it is difficult to delineate their contribution from general impairments in memory produced by etiology and seizures. We investigated the transient impact of focal IISs on the hippocampus, a structure crucial for learning and memory and yet highly prone to IISs in temporal lobe epilepsy (TLE). METHODS Bilateral hippocampal depth electrodes were implanted into 14 Sprague-Dawley rats, followed by intrahippocampal pilocarpine or saline infusion unilaterally. Rats that developed chronic spikes were trained in a hippocampal-dependent operant behavior task, delayed-match-to-sample. Depth-electroencephalogram (EEG) was recorded during 5,562 trials among five rats, and within-subject analyses evaluated the impact of hippocampal spikes on short-term memory operations. RESULTS Hippocampal spikes that occurred during memory retrieval strongly impaired performance (p < 0.001). However, spikes that occurred during memory encoding or memory maintenance did not affect performance in those trials. Hippocampal spikes also affected response latency, adding approximately 0.48 seconds to the time taken to respond (p < 0.001). INTERPRETATION We found that focal IIS-related interference in cognition extends to structures in the limbic system, which required intrahippocampal recordings. Hippocampal spikes seem most harmful if they occur when hippocampal function is critical, extending human studies showing that cortical spikes are most disruptive during active cortical functioning. The cumulative effects of spikes could therefore impact general cognitive functioning. These results strengthen the argument that suppression of IISs may improve memory and cognitive performance in patients with epilepsy.
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Affiliation(s)
- Jonathan K Kleen
- Department of Neurology, Neuroscience Center at Dartmouth, Dartmouth Medical School, Hanover, New Hampshire
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Dupont S, Duron E, Samson S, Denos M, Volle E, Delmaire C, Navarro V, Chiras J, Lehéricy S, Samson Y, Baulac M. Functional MR Imaging or Wada Test: Which Is the Better Predictor of Individual Postoperative Memory Outcome? Radiology 2010; 255:128-34. [PMID: 20308450 DOI: 10.1148/radiol.09091079] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sophie Dupont
- Epilepsy Unit, Neurology Clinic Paul Castaigne, Hôpital de la Pitié-Salpêtrière, APHP, 47 boulevard de l'Hôpital, 75651 Paris cedex 13, France.
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95
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HAMED SHERIFAA. THE RATIONALE FOR NEUROPROTECTION IN EPILEPSY: STEPS FORWARD FOR NEW THERAPEUTIC AND PREVENTIVE STRATEGIES. J Integr Neurosci 2010. [DOI: 10.1142/s0219635210002378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Haag A, Barth S, Zibelius M, Hermsen A, Menzler K, Oertel WH, Hamer HM, Rosenow F, Knake S. Memory for public events in patients with unilateral temporal lobe epilepsy. Epilepsy Behav 2010; 17:246-51. [PMID: 20093096 DOI: 10.1016/j.yebeh.2009.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/23/2009] [Accepted: 12/19/2009] [Indexed: 11/16/2022]
Abstract
Memory for public events (PEs) was assessed as a marker of remote declarative memory in 36 patients with temporal lobe epilepsy (TLE) and compared with that of 19 patients with extra-TLE (ETLE), 17 patients with idiopathic generalized epilepsy (IGE), and 23 healthy volunteers. Verbal IQ, inventory-based evidence of depression, handedness, onset of illness, disease duration, and medication were obtained. Memory for PEs was reduced in all patient groups (TLE, P<0.0001; ETLE, P=0.009; IGE, P=0.008). The TLE group showed reduced memory for PEs compared with the other patients with epilepsy (P=0.001). A time gradient was observed, with worse memory for PEs of the 1990 s and for PEs that occurred after onset of illness. Our data support the key role of the temporal lobe in remote declarative memory. With patients with TLE remembering fewer PEs from the period after onset of epilepsy, the deficits can be partly attributed to unsuccessful consolidation rather than retrieval difficulties alone.
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Affiliation(s)
- Anja Haag
- Interdisciplinary Epilepsy Center, Department of Neurology, Philipps-Universität Marburg, Marburg, Germany.
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97
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Hoppe C, Stojanovic J, Elger CE. Enhancing memory for lists by grouped presentation and rehearsal: a pilot study in healthy subjects with unexpected results. Seizure 2009; 18:711-5. [PMID: 19875311 DOI: 10.1016/j.seizure.2009.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/29/2009] [Accepted: 10/02/2009] [Indexed: 10/20/2022] Open
Abstract
List learning is probably the most established paradigm for the psychometric evaluation of episodic memory deficits in different neuropsychiatric conditions including epilepsy. Strategies which are capable of increasing the test performance might be promising candidates for a therapeutic improvement of daily memory performance. Based on the classical 'temporal grouping effect' we wanted to evaluate the memory-enhancing potential of disentangling perceiving, rehearsing and encoding by temporally grouped presentation and group-wise reproduction during acquisition. According to the ethical principle of subsidiary the study was performed in healthy adolescents (N=126) before setting-up a patient study. Subjects had to learn a list of 12 semantically unrelated nouns and a list of 12 figures during two acquisition trials under one of four experimental conditions defined by the size of presented item groups (GS): GS=1 (single items, i.e., 12 x 1 item), GS=3 (4 x 3 items), GS=6 (2 x 6 items), and GS=12 (standard presentation mode, i.e., 1 x 12 items). Repeated measures MANOVA confirmed a positive effect of smaller GS on acquisition performance but the grouping condition obtained no effect on immediate and delayed free recall or on yes/no recognition. For verbal retention, GS=12 even showed a tendency toward an advantage as compared to GS=3. Although appearing reasonable and promising, facilitating acquisition during list learning by temporal grouping and grouped overt rehearsal turned out to be ineffective with regard to long-term memory encoding and retrieval. A strategy however which fails in healthy subjects is unlikely to obtain a therapeutic potential in patients with memory deficits.
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Affiliation(s)
- Christian Hoppe
- Department of Epileptology, University of Bonn Medical Centre, Sigmund-Freud-Strasse 25, FRG-53105 Bonn, Germany.
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Lin H, Holmes GL, Kubie JL, Muller RU. Recurrent seizures induce a reversible impairment in a spatial hidden goal task. Hippocampus 2009; 19:817-27. [PMID: 19235227 DOI: 10.1002/hipo.20565] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A major question concerning the learning and memory deficits characteristic of epilepsy is the relative importance of the initial insult that leads to recurrent, unprovoked seizures versus the seizures themselves. A related issue is whether seizure-induced cognitive decline is permanent or reversible when convulsions cease. To address these problems, adult rats were extensively trained in the "spatial accuracy task," a dry-land analog of the Morris water maze. This task allows the rat's estimate of the location of a hidden goal zone to be repeatedly measured within each behavioral session. One aim was to measure, in well-trained animals, the time course of any cognitive impairment caused by a daily flurothyl-induced generalized seizure over 11 days. A second aim was to look for possible recovery during 9 subsequent days with no seizures. We saw a cumulative degradation in spatial performance during the seizure days and reversal of the deficit after seizures were stopped such that performance returned to baseline. Interestingly, the rate of learning to an asymptote, the rate of performance decline during one-per-day seizures and the rate of relearning during the recovery period were all similar. Given that the hippocampus plays an important role in spatial memory and that it is the brain structure most vulnerable to abnormal excitation the implication is that the hippocampus remains essential for precise spatial navigation even after prolonged training in locating a fixed goal zone. Clinically, this finding questions the assumption that patients who experience seizures should return to a baseline cognitive level within hours.
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Affiliation(s)
- Hai Lin
- Program in Neural and Behavioral Science, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
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99
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Epsztein J, Sola E, Represa A, Ben-Ari Y, Crépel V. A selective interplay between aberrant EPSPKA and INaP reduces spike timing precision in dentate granule cells of epileptic rats. ACTA ACUST UNITED AC 2009; 20:898-911. [PMID: 19684246 PMCID: PMC2837093 DOI: 10.1093/cercor/bhp156] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Spike timing precision is a fundamental aspect of neuronal information processing in the brain. Here we examined the temporal precision of input–output operation of dentate granule cells (DGCs) in an animal model of temporal lobe epilepsy (TLE). In TLE, mossy fibers sprout and establish recurrent synapses on DGCs that generate aberrant slow kainate receptor–mediated excitatory postsynaptic potentials (EPSPKA) not observed in controls. We report that, in contrast to time-locked spikes generated by EPSPAMPA in control DGCs, aberrant EPSPKA are associated with long-lasting plateaus and jittered spikes during single-spike mode firing. This is mediated by a selective voltage-dependent amplification of EPSPKA through persistent sodium current (INaP) activation. In control DGCs, a current injection of a waveform mimicking the slow shape of EPSPKA activates INaP and generates jittered spikes. Conversely in epileptic rats, blockade of EPSPKA or INaP restores the temporal precision of EPSP–spike coupling. Importantly, EPSPKA not only decrease spike timing precision at recurrent mossy fiber synapses but also at perforant path synapses during synaptic integration through INaP activation. We conclude that a selective interplay between aberrant EPSPKA and INaP severely alters the temporal precision of EPSP–spike coupling in DGCs of chronic epileptic rats.
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Affiliation(s)
- Jérôme Epsztein
- INMED, INSERM U901, Université de La Méditerranée, Parc scientifique de Luminy, BP 13, 13273, Marseille Cedex 09, France
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Dabbs K, Jones J, Seidenberg M, Hermann B. Neuroanatomical correlates of cognitive phenotypes in temporal lobe epilepsy. Epilepsy Behav 2009; 15:445-51. [PMID: 19560403 PMCID: PMC2758317 DOI: 10.1016/j.yebeh.2009.05.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 05/22/2009] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Previous research characterized three cognitive phenotypes in temporal lobe epilepsy, each associated with a different profile of clinical seizure and demographic characteristics, total cerebral (gray, white, cerebrospinal fluid) and hippocampal volumes, and prospective cognitive trajectories. The objective of this investigation was to characterize in detail the specific neuroanatomical abnormalities associated with each cognitive phenotype. METHODS High-resolution MRI scans of healthy controls (n=53) and patients with temporal lobe epilepsy (n=55), grouped by cognitive phenotype (minimally impaired; memory impaired; memory, executive function, and speed impaired), were examined with respect to patterns of gray matter thickness throughout the cortical mantle, as well as volumes of subcortical structures, corpus callosum, and regions of the cerebellum. RESULTS Increasing abnormalities in temporal and extratemporal cortical thickness, volumes of subcortical structures (hippocampus, thalamus, basal ganglia), all regions of the corpus callosum, and bilateral cerebellar gray matter distinguish the cognitive phenotypes in a generally stepwise fashion. The most intact anatomy is observed in the minimally impaired epilepsy group and the most abnormal anatomy is evident in the epilepsy group with impairments in memory, executive function, and speed. CONCLUSION Empirically derived cognitive phenotypes are associated with the presence, severity, and distribution of anatomic abnormalities in widely distributed cortical, subcortical, callosal, and cerebellar networks.
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Affiliation(s)
- Kevin Dabbs
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Jana Jones
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Michael Seidenberg
- Department of Psychology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois
| | - Bruce Hermann
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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