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Mitchnick KA, Marlatte H, Belchev Z, Gao F, Rosenbaum RS. Differential contributions of the hippocampal dentate gyrus and CA1 subfield to mnemonic discrimination. Hippocampus 2024; 34:278-283. [PMID: 38501294 DOI: 10.1002/hipo.23604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 02/27/2024] [Accepted: 03/06/2024] [Indexed: 03/20/2024]
Abstract
Evidence suggests that individual hippocampal subfields are preferentially involved in various memory-related processes. Here, we demonstrated dissociations in these memory processes in two unique individuals with near-selective bilateral damage within the hippocampus, affecting the dentate gyrus (DG) in case BL and the cornu ammonis 1 (CA1) subfield in case BR. BL was impaired in discriminating highly similar objects in memory (i.e., mnemonic discrimination) but exhibited preserved overall recognition of studied objects, regardless of similarity. Conversely, BR demonstrated impaired general recognition. These results provide evidence for the DG in discrimination processes, likely related to underlying pattern separation computations, and the CA1 in retention/retrieval.
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Affiliation(s)
- Krista A Mitchnick
- Department of Psychology, York University, Toronto, Ontario, Canada
- Rotman Research Institute at Baycrest Hospital, Toronto, Ontario, Canada
| | - Hannah Marlatte
- Rotman Research Institute at Baycrest Hospital, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Zorry Belchev
- Rotman Research Institute at Baycrest Hospital, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Fuqiang Gao
- Cognitive Neurology Research Group, Sunnybrook Hospital, Toronto, Ontario, Canada
| | - R Shayna Rosenbaum
- Department of Psychology, York University, Toronto, Ontario, Canada
- Rotman Research Institute at Baycrest Hospital, Toronto, Ontario, Canada
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2
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Mohammadi E, Nikbakht F, Vazifekhah S, Babae JF, Jogataei MT. Evaluation the cognition-improvement effects of N-acetyl cysteine in experimental temporal lobe epilepsy in rat. Behav Brain Res 2023; 440:114263. [PMID: 36563904 DOI: 10.1016/j.bbr.2022.114263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Memory impairment is a critical issue in patients with temporal lobe epilepsy (TLE). Neuronal loss within the hippocampus and recurrent seizures may cause cognitive impairment in TLE. N -acetyl cysteine (NAC) is a sulfur-containing amino acid cysteine that is currently being investigated due to its protective effects on neurodegenerative disorders. NAC was orally administrated at a dose of 100 mg/kg for 8 days (7-day pretreatment and 1-day post-surgery). Neuronal viability, mTOR protein level, and spatial memory were detected in the kainite temporal epilepsy model via Nissl staining, western blot method, and Morris water maze task, respectively. Results showed that NAC delayed seizure activity and ameliorated memory deficit induced by Kainic acid. Histological analysis showed that NAC significantly increased the number of intact neurons in CA3 and hilar areas of the hippocampus following the induction of epilepsy. NAC also modulated the mTOR protein level 5 days after epilepsy compared to the KA-induced group. CONCLUSION: These results suggest that NAC improved memory impairment via anticonvulsant and neuroprotective activity and, in all probability, by lowering the level of mTOR.
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Affiliation(s)
- Ekram Mohammadi
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, University of Medical Sciences, Tehran Iran
| | - Farnaz Nikbakht
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, University of Medical Sciences, Tehran Iran.
| | - Somayeh Vazifekhah
- Department of Basic Sciences, Sari Branch. Islamic Azad University, Sari, Iran
| | - Javad Fahanik Babae
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohamad Taghi Jogataei
- Cellular and Molecular Research Center and Department of Anatomy, School of Medicine, University of Medical Sciences, Tehran Iran
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3
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Comino Garcia-Munoz A, Alemán-Gómez Y, Toledano R, Poch C, García-Morales I, Aledo-Serrano Á, Gil-Nagel A, Campo P. Morphometric and microstructural characteristics of hippocampal subfields in mesial temporal lobe epilepsy and their correlates with mnemonic discrimination. Front Neurol 2023; 14:1096873. [PMID: 36864916 PMCID: PMC9972498 DOI: 10.3389/fneur.2023.1096873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/18/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction Pattern separation (PS) is a fundamental aspect of memory creation that defines the ability to transform similar memory representations into distinct ones, so they do not overlap when storing and retrieving them. Experimental evidence in animal models and the study of other human pathologies have demonstrated the role of the hippocampus in PS, in particular of the dentate gyrus (DG) and CA3. Patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HE) commonly report mnemonic deficits that have been associated with failures in PS. However, the link between these impairments and the integrity of the hippocampal subfields in these patients has not yet been determined. The aim of this work is to explore the association between the ability to perform mnemonic functions and the integrity of hippocampal CA1, CA3, and DG in patients with unilateral MTLE-HE. Method To reach this goal we evaluated the memory of patients with an improved object mnemonic similarity test. We then analyzed the hippocampal complex structural and microstructural integrity using diffusion weighted imaging. Results Our results indicate that patients with unilateral MTLE-HE present alterations in both volume and microstructural properties at the level of the hippocampal subfields DG, CA1, CA3, and the subiculum, that sometimes depend on the lateralization of their epileptic focus. However, none of the specific changes was found to be directly related to the performance of the patients in a pattern separation task, which might indicate a contribution of various alterations to the mnemonic deficits or the key contribution of other structures to the function. Discussion we established for the first time the alterations in both the volume and the microstructure at the level of the hippocampal subfields in a group of unilateral MTLE patients. We observed that these changes are greater in the DG and CA1 at the macrostructural level, and in CA3 and CA1 in the microstructural level. None of these changes had a direct relation to the performance of the patients in a pattern separation task, which suggests a contribution of various alterations to the loss of function.
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Affiliation(s)
- Alicia Comino Garcia-Munoz
- Centre de Résonance Magnétique Biologique et Médicale-Unité Mixte de Recherche 7339, Aix-Marseille Université, Marseille, France
| | - Yasser Alemán-Gómez
- Connectomics Lab, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Rafael Toledano
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain,Epilepsy Unit, Neurology Department, University Hospital Ramón y Cajal, Madrid, Spain
| | - Claudia Poch
- Facultad de Lenguas y Educación, Universidad de Nebrija, Madrid, Spain
| | - Irene García-Morales
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain,Epilepsy Unit, Neurology Department, University Hospital of San Carlos, Madrid, Spain
| | - Ángel Aledo-Serrano
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain
| | - Antonio Gil-Nagel
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain
| | - Pablo Campo
- Department of Basic Psychology, Autonoma University of Madrid, Madrid, Spain,*Correspondence: Pablo Campo ✉
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Lalani SJ, Reyes A, Kaestner E, Stark SM, Stark CEL, Lee D, Kansal L, Shih JJ, Smith CN, Paul BM, McDonald CR. Impaired Behavioral Pattern Separation in Refractory Temporal Lobe Epilepsy and Mild Cognitive Impairment. J Int Neuropsychol Soc 2022; 28:550-562. [PMID: 34078506 PMCID: PMC8965747 DOI: 10.1017/s1355617721000734] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Episodic memory impairment and hippocampal pathology are hallmark features of both temporal lobe epilepsy (TLE) and amnestic mild cognitive impairment (aMCI). Pattern separation (PS), which enables the distinction between similar but unique experiences, is thought to contribute to successful encoding and retrieval of episodic memories. Impaired PS has been proposed as a potential mechanism underling episodic memory impairment in aMCI, but this association is less established in TLE. In this study, we examined behavioral PS in patients with TLE and explored whether profiles of performance in TLE are similar to aMCI. METHOD Patients with TLE, aMCI, and age-matched, healthy controls (HCs) completed a modified recognition task that relies on PS for the discrimination of highly similar lure items, the Mnemonic Similarity Task (MST). Group differences were evaluated and relationships between clinical characteristics, California Verbal Learning Test-Second Edition scores, and MST performance were tested in the TLE group. RESULTS Patients with TLE and aMCI demonstrated poorer PS performance relative to the HCs, but performance did not differ between the two patient groups. Neither the side of seizure focus nor having hippocampal sclerosis affected performance in TLE. However, TLE patients with clinically defined memory impairment showed the poorest performance. CONCLUSION Memory performance on a task that relies on PS was disrupted to a similar extent in TLE and aMCI. The MST could provide a clinically useful tool for measuring hippocampus-dependent memory impairments in TLE and other neurological disorders associated with hippocampal damage.
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Affiliation(s)
- Sanam J Lalani
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Anny Reyes
- San Diego State University, University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA
- Center for Multimodal Imaging and Genetics, University of California, San Diego, CA, USA
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Erik Kaestner
- Center for Multimodal Imaging and Genetics, University of California, San Diego, CA, USA
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Shauna M Stark
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - Craig E L Stark
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - David Lee
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Leena Kansal
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Jerry J Shih
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Christine N Smith
- Department of Psychiatry, University of California, San Diego, CA, USA
- Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, USA
| | - Brianna M Paul
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Carrie R McDonald
- San Diego State University, University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA
- Center for Multimodal Imaging and Genetics, University of California, San Diego, CA, USA
- Department of Psychiatry, University of California, San Diego, CA, USA
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5
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Khalife MR, Scott RC, Hernan AE. Mechanisms for Cognitive Impairment in Epilepsy: Moving Beyond Seizures. Front Neurol 2022; 13:878991. [PMID: 35645970 PMCID: PMC9135108 DOI: 10.3389/fneur.2022.878991] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
There has been a major emphasis on defining the role of seizures in the causation of cognitive impairments like memory deficits in epilepsy. Here we focus on an alternative hypothesis behind these deficits, emphasizing the mechanisms of information processing underlying healthy cognition characterized as rate, temporal and population coding. We discuss the role of the underlying etiology of epilepsy in altering neural networks thereby leading to both the propensity for seizures and the associated cognitive impairments. In addition, we address potential treatments that can recover the network function in the context of a diseased brain, thereby improving both seizure and cognitive outcomes simultaneously. This review shows the importance of moving beyond seizures and approaching the deficits from a system-level perspective with the guidance of network neuroscience.
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Affiliation(s)
- Mohamed R. Khalife
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
| | - Rod C. Scott
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
- Institute of Child Health, Neurosciences Unit University College London, London, United Kingdom
| | - Amanda E. Hernan
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
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6
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Dohm-Hansen S, Donoso F, Lucassen PJ, Clarke G, Nolan YM. The gut microbiome and adult hippocampal neurogenesis: A new focal point for epilepsy? Neurobiol Dis 2022; 170:105746. [DOI: 10.1016/j.nbd.2022.105746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/13/2022] [Accepted: 04/29/2022] [Indexed: 02/07/2023] Open
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Rodriguez-Cruces R, Royer J, Larivière S, Bassett DS, Caciagli L, Bernhardt BC. Multimodal connectome biomarkers of cognitive and affective dysfunction in the common epilepsies. Netw Neurosci 2022; 6:320-338. [PMID: 35733426 PMCID: PMC9208009 DOI: 10.1162/netn_a_00237] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 02/02/2022] [Indexed: 11/05/2022] Open
Abstract
Epilepsy is one of the most common chronic neurological conditions, traditionally defined as a disorder of recurrent seizures. Cognitive and affective dysfunction are increasingly recognized as core disease dimensions and can affect patient well-being, sometimes more than the seizures themselves. Connectome-based approaches hold immense promise for revealing mechanisms that contribute to dysfunction and to identify biomarkers. Our review discusses emerging multimodal neuroimaging and connectomics studies that highlight network substrates of cognitive/affective dysfunction in the common epilepsies. We first discuss work in drug-resistant epilepsy syndromes, that is, temporal lobe epilepsy, related to mesiotemporal sclerosis (TLE), and extratemporal epilepsy (ETE), related to malformations of cortical development. While these are traditionally conceptualized as ‘focal’ epilepsies, many patients present with broad structural and functional anomalies. Moreover, the extent of distributed changes contributes to difficulties in multiple cognitive domains as well as affective-behavioral challenges. We also review work in idiopathic generalized epilepsy (IGE), a subset of generalized epilepsy syndromes that involve subcortico-cortical circuits. Overall, neuroimaging and network neuroscience studies point to both shared and syndrome-specific connectome signatures of dysfunction across TLE, ETE, and IGE. Lastly, we point to current gaps in the literature and formulate recommendations for future research. Epilepsy is increasingly recognized as a network disorder characterized by recurrent seizures as well as broad-ranging cognitive difficulties and affective dysfunction. Our manuscript reviews recent literature highlighting brain network substrates of cognitive and affective dysfunction in common epilepsy syndromes, namely temporal lobe epilepsy secondary to mesiotemporal sclerosis, extratemporal epilepsy secondary to malformations of cortical development, and idiopathic generalized epilepsy syndromes arising from subcortico-cortical pathophysiology. We discuss prior work that has indicated both shared and distinct brain network signatures of cognitive and affective dysfunction across the epilepsy spectrum, improves our knowledge of structure-function links and interindividual heterogeneity, and ultimately aids screening and monitoring of therapeutic strategies.
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Affiliation(s)
- Raul Rodriguez-Cruces
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jessica Royer
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Sara Larivière
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Dani S. Bassett
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
| | - Lorenzo Caciagli
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Boris C. Bernhardt
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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8
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Mátyás A, Borbély E, Mihály A. Hippocampal Sclerosis in Pilocarpine Epilepsy: Survival of Peptide-Containing Neurons and Learning and Memory Disturbances in the Adult NMRI Strain Mouse. Int J Mol Sci 2021; 23:ijms23010204. [PMID: 35008630 PMCID: PMC8745054 DOI: 10.3390/ijms23010204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 12/21/2021] [Accepted: 12/23/2021] [Indexed: 12/28/2022] Open
Abstract
The present experiments reveal the alterations of the hippocampal neuronal populations in chronic epilepsy. The mice were injected with a single dose of pilocarpine. They had status epilepticus and spontaneously recurrent motor seizures. Three months after pilocarpine treatment, the animals were investigated with the Barnes maze to determine their learning and memory capabilities. Their hippocampi were analyzed 2 weeks later (at 3.5 months) with standard immunohistochemical methods and cell counting. Every animal displayed hippocampal sclerosis. The neuronal loss was evaluated with neuronal-N immunostaining, and the activation of the microglia was measured with Iba1 immunohistochemistry. The neuropeptide Y, parvalbumin, and calretinin immunoreactive structures were qualitatively and quantitatively analyzed in the hippocampal formation. The results were compared statistically to the results of the control mice. We detected neuronal loss and strongly activated microglia populations. Neuropeptide Y was significantly upregulated in the sprouting axons. The number of parvalbumin- and calretinin-containing interneurons decreased significantly in the Ammon’s horn and dentate gyrus. The epileptic animals displayed significantly worse learning and memory functions. We concluded that degeneration of the principal neurons, a numerical decrease of PV-containing GABAergic neurons, and strong peptidergic axonal sprouting were responsible for the loss of the hippocampal learning and memory functions.
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Affiliation(s)
- Adrienne Mátyás
- Department of Anatomy, Albert Szent-Györgyi Faculty of Medicine, University of Szeged, Kossuth L. sgt. 38, H-6724 Szeged, Hungary;
| | - Emőke Borbély
- Department of Medical Chemistry, University of Szeged, Dóm tér. 8, H-6720 Szeged, Hungary;
- Professional Pedagogical Service of Csongrád-Csanád County, Űrhajós u. 4, H-6723 Szeged, Hungary
| | - András Mihály
- Department of Anatomy, Albert Szent-Györgyi Faculty of Medicine, University of Szeged, Kossuth L. sgt. 38, H-6724 Szeged, Hungary;
- Correspondence:
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9
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Deficits in Behavioral and Neuronal Pattern Separation in Temporal Lobe Epilepsy. J Neurosci 2021; 41:9669-9686. [PMID: 34620720 PMCID: PMC8612476 DOI: 10.1523/jneurosci.2439-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 09/09/2021] [Accepted: 09/21/2021] [Indexed: 11/21/2022] Open
Abstract
In temporal lobe epilepsy, the ability of the dentate gyrus to limit excitatory cortical input to the hippocampus breaks down, leading to seizures. The dentate gyrus is also thought to help discriminate between similar memories by performing pattern separation, but whether epilepsy leads to a breakdown in this neural computation, and thus to mnemonic discrimination impairments, remains unknown. Here we show that temporal lobe epilepsy is characterized by behavioral deficits in mnemonic discrimination tasks, in both humans (females and males) and mice (C57Bl6 males, systemic low-dose kainate model). Using a recently developed assay in brain slices of the same epileptic mice, we reveal a decreased ability of the dentate gyrus to perform certain forms of pattern separation. This is because of a subset of granule cells with abnormal bursting that can develop independently of early EEG abnormalities. Overall, our results linking physiology, computation, and cognition in the same mice advance our understanding of episodic memory mechanisms and their dysfunction in epilepsy.SIGNIFICANCE STATEMENT People with temporal lobe epilepsy (TLE) often have learning and memory impairments, sometimes occurring earlier than the first seizure, but those symptoms and their biological underpinnings are poorly understood. We focused on the dentate gyrus, a brain region that is critical to avoid confusion between similar memories and is anatomically disorganized in TLE. We show that both humans and mice with TLE experience confusion between similar situations. This impairment coincides with a failure of the dentate gyrus to disambiguate similar input signals because of pathologic bursting in a subset of neurons. Our work bridges seizure-oriented and memory-oriented views of the dentate gyrus function, suggests a mechanism for cognitive symptoms in TLE, and supports a long-standing hypothesis of episodic memory theories.
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10
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Wong-Goodrich SJE, Kearley J. Strenuous Exercise Habits and Spatial Mnemonic Discrimination Ability in Young Adult Men and Women. Percept Mot Skills 2021; 128:2346-2366. [PMID: 34365862 DOI: 10.1177/00315125211038732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Increased physical activity has shown positive effects on various hippocampal memory functions through accumulating evidence that physical exercise and higher cardiorespiratory fitness can enhance human performance on nonspatial mnemonic discrimination tasks that rely on hippocampal pattern separation. However, there is less direct evidence of exercise effects on spatial pattern separation in humans, despite evidence for this association in rodent models. We examined the influence of strenuous exercise habits on spatial mnemonic discrimination among 176 young adults. We used a delayed match-/non-match-to-sample (same/different) task to assess pattern separation for spatial locations across varying degrees of similarity. Participants who reported regularly engaging in strenuous exercise three or more times per week performed significantly better than those who reported engaging in strenuous exercise fewer than three times per week, even when pattern separation tasks involved higher spatial similarity. These apparent exercise effects were observed for female, but not male, participants. These findings support likely benefits of strenuous exercise habits for human spatial pattern separation skills, and they suggest a need to explore potential interaction effects of exercise and gender.
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Affiliation(s)
| | - Julia Kearley
- Department of Psychology, Iona College, New Rochelle, New York, United States
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11
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Operto FF, Pastorino GMG, Di Bonaventura C, Scuoppo C, Padovano C, Vivenzio V, Donadio S, Coppola G. Effects of antiseizure monotherapy on visuospatial memory in pediatric age. Eur J Paediatr Neurol 2021; 32:106-114. [PMID: 33895643 DOI: 10.1016/j.ejpn.2021.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/08/2021] [Accepted: 04/10/2021] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Visuospatial abilities are fundamental for good school achievements and good daily functioning. Previous studies showed an impairment of visuospatial skills in pediatric patients with epilepsy; pharmacological treatment, although indispensable for the seizure control, could further affect cognitive functions. The aim of our study was to evaluate the visuospatial skills in children and adolescents with different forms of epilepsy well-controlled by antiseizure monotherapy, both at baseline and after one year follow-up, through a standardized neuropsychological assessment. METHODS We recruited 207 children and adolescents (mean age = 10.35 ± 2.39 years) with epilepsy, well controlled by monotherapy with levetiracetam, valproic acid, ethosuximide, oxcarbazepine or carbamazepine and 45 age/sex-matched controls. All the participants performed the Rey-Osterrieth Complex Figure, a standardized test for visuospatial perception and visuospatial memory assessment, at baseline and after 12 month of drug therapy. Age, sex, executive functions, non-verbal intelligence, age at onset of epilepsy, epilepsy duration, epilepsy type, lobe and side of seizure onset were considered in our analysis. EEG, seizure frequency, and drug dose were also recorded. RESULTS At baseline, the epilepsy group performed significantly worse than controls in the Immediate Recall test but not the Direct Copy test, without differences between epilepsy subgroups. Immediate Recall scores were related to age of seizure onset and epilepsy duration and executive functions. The re-assessment after 1 year showed that the Immediate Recall mean scores were not significantly changed in the levetiracetam and oxcarbazepine group, while they significantly worsened in the valproic acid, ethosuximide and carbamazepine groups. The Immediate Recall scores were correlated to age, age at onset of epilepsy, epilepsy duration, and executive functions. CONCLUSIONS Children with epilepsy may exhibit visuospatial memory impairment compared to their peer, that may be correlated to some features of the epilepsy itself and to the impairment of executive functions. Different antiseizure medications can affect visuospatial memory differently, so it is important monitoring this aspect in pediatric patients.
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Affiliation(s)
- Francesca Felicia Operto
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy.
| | - Grazia Maria Giovanna Pastorino
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Carlo Di Bonaventura
- Epilepsy Unit, Department of Human Neurosciences, "Sapienza" University of Rome, Rome, Italy
| | - Chiara Scuoppo
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Chiara Padovano
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Valentina Vivenzio
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Serena Donadio
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Giangennaro Coppola
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
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Li Q, Tavakol S, Royer J, Larivière S, Vos De Wael R, Park BY, Paquola C, Zeng D, Caldairou B, Bassett DS, Bernasconi A, Bernasconi N, Frauscher B, Smallwood J, Caciagli L, Li S, Bernhardt BC. Atypical neural topographies underpin dysfunctional pattern separation in temporal lobe epilepsy. Brain 2021; 144:2486-2498. [PMID: 33730163 DOI: 10.1093/brain/awab121] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/26/2021] [Accepted: 02/11/2021] [Indexed: 12/14/2022] Open
Abstract
Episodic memory is the ability to accurately remember events from our past. The process of pattern separation is hypothesized to underpin this ability and is defined as the ability to orthogonalize memory traces, to maximize the features that make them unique. Contemporary cognitive neuroscience suggests that pattern separation entails complex interactions between the hippocampus and the neocortex, where specific hippocampal subregions shape neural reinstatement in the neocortex. To test this hypothesis, the current work studied both healthy controls and patients with temporal lobe epilepsy (TLE) who present with hippocampal structural anomalies. In all participants, we measured neural activity using functional magnetic resonance imaging (fMRI) while they retrieved memorized items compared to lure items which share features with the target. Behaviorally, TLE patients were less able to exclude lures than controls, and showed a reduction in pattern separation. To assess the hypothesized relationship between neural patterns in the hippocampus and the neocortex, we identified topographic gradients of intrinsic connectivity along neocortical and hippocampal subfield surfaces and identified the topographic profile of the neural activity accompanying pattern separation. In healthy controls, pattern separation followed a graded pattern of neural activity, both along the hippocampal long axis (and peaked in anterior segments that are more heavily engaged in transmodal processing) and along the neocortical hierarchy running from unimodal to transmodal regions (peaking in transmodal default mode regions). In TLE patients, however, this concordance between task-based functional activations and topographic gradients was markedly reduced. Furthermore, person specific measures of concordance between task-related activity and connectivity gradients in patients and controls related to inter-individual differences in behavioral measures of pattern separation and episodic memory, highlighting the functional relevance of the observed topographic motifs. Our work is consistent with an emerging understanding that successful discrimination between memories with similar features entails a shift in the locus of neural activity away from sensory systems, a pattern that is mirrored along the hippocampal long axis and with respect to neocortical hierarchies. More broadly, our study establishes topographic profiling using intrinsic connectivity gradients captures the functional underpinnings of episodic memory processes in manner that is sensitive to their reorganization in pathology.
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Affiliation(s)
- Qiongling Li
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.,School of Biological Science and Medical Engineering, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China
| | - Shahin Tavakol
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Jessica Royer
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Sara Larivière
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Reinder Vos De Wael
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Bo-Yong Park
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Casey Paquola
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Debin Zeng
- School of Biological Science and Medical Engineering, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China
| | - Benoit Caldairou
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Danielle S Bassett
- Department of Bioengineering, University of Pennsylvania, Philadelphia, USA.,Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA.,Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, USA.,Department of Psychiatry, University of Pennsylvania, Philadelphia, USA.,Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Andrea Bernasconi
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Neda Bernasconi
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Birgit Frauscher
- Montreal Neurological Institute, McGill University, Montreal, Canada
| | | | - Lorenzo Caciagli
- Department of Bioengineering, University of Pennsylvania, Philadelphia, USA
| | - Shuyu Li
- School of Biological Science and Medical Engineering, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China
| | - Boris C Bernhardt
- Multimodal Imaging and Connectome Analysis Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
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13
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Lenck-Santini PP, Sakkaki S. Alterations of Neuronal Dynamics as a Mechanism for Cognitive Impairment in Epilepsy. Curr Top Behav Neurosci 2021; 55:65-106. [PMID: 33454922 DOI: 10.1007/7854_2020_193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Epilepsy is commonly associated with cognitive and behavioral deficits that dramatically affect the quality of life of patients. In order to identify novel therapeutic strategies aimed at reducing these deficits, it is critical first to understand the mechanisms leading to cognitive impairments in epilepsy. Traditionally, seizures and epileptiform activity in addition to neuronal injury have been considered to be the most significant contributors to cognitive dysfunction. In this review we however highlight the role of a new mechanism: alterations of neuronal dynamics, i.e. the timing at which neurons and networks receive and process neural information. These alterations, caused by the underlying etiologies of epilepsy syndromes, are observed in both animal models and patients in the form of abnormal oscillation patterns in unit firing, local field potentials, and electroencephalogram (EEG). Evidence suggests that such mechanisms significantly contribute to cognitive impairment in epilepsy, independently of seizures and interictal epileptiform activity. Therefore, therapeutic strategies directly targeting neuronal dynamics rather than seizure reduction may significantly benefit the quality of life of patients.
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Affiliation(s)
- Pierre-Pascal Lenck-Santini
- Aix-Marseille Université, INSERM, INMED, Marseille, France. .,Department of Neurological sciences, University of Vermont, Burlington, VT, USA.
| | - Sophie Sakkaki
- Department of Neurological sciences, University of Vermont, Burlington, VT, USA.,Université de. Montpellier, CNRS, INSERM, IGF, Montpellier, France
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14
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Mechanism of seizure-induced retrograde amnesia. Prog Neurobiol 2020; 200:101984. [PMID: 33388373 DOI: 10.1016/j.pneurobio.2020.101984] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/09/2020] [Accepted: 12/22/2020] [Indexed: 11/21/2022]
Abstract
Seizures cause retrograde amnesia, but underlying mechanisms are poorly understood. We tested whether seizure activated neuronal circuits overlap with spatial memory engram and whether seizures saturate LTP in engram cells. A seizure caused retrograde amnesia for spatial memory task. Spatial learning and a seizure caused cFos expression and synaptic plasticity overlapping set of neurons in the CA1 of the hippocampus. Recordings from learning-labeled CA1 pyramidal neurons showed potentiated synapses. Seizure-tagged neurons were also more excitable with larger rectifying excitatory postsynaptic currents than surrounding unlabeled neurons. These neurons had enlarged dendritic spines and saturated LTP. A seizure immediately after learning, reset the memory engram. Seizures cause retrograde amnesia through shared ensembles and mechanisms.
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15
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Larivière S, Bernasconi A, Bernasconi N, Bernhardt BC. Connectome biomarkers of drug-resistant epilepsy. Epilepsia 2020; 62:6-24. [PMID: 33236784 DOI: 10.1111/epi.16753] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/29/2020] [Accepted: 10/16/2020] [Indexed: 02/06/2023]
Abstract
Drug-resistant epilepsy (DRE) considerably affects patient health, cognition, and well-being, and disproportionally contributes to the overall burden of epilepsy. The most common DRE syndromes are temporal lobe epilepsy related to mesiotemporal sclerosis and extratemporal epilepsy related to cortical malformations. Both syndromes have been traditionally considered as "focal," and most patients benefit from brain surgery for long-term seizure control. However, increasing evidence indicates that many DRE patients also present with widespread structural and functional network disruptions. These anomalies have been suggested to relate to cognitive impairment and prognosis, highlighting their importance for patient management. The advent of multimodal neuroimaging and formal methods to quantify complex systems has offered unprecedented ability to profile structural and functional brain networks in DRE patients. Here, we performed a systematic review on existing DRE network biomarker candidates and their contribution to three key application areas: (1) modeling of cognitive impairments, (2) localization of the surgical target, and (3) prediction of clinical and cognitive outcomes after surgery. Although network biomarkers hold promise for a range of clinical applications, translation of neuroimaging biomarkers to the patient's bedside has been challenged by a lack of clinical and prospective studies. We therefore close by highlighting conceptual and methodological strategies to improve the evaluation and accessibility of network biomarkers, and ultimately guide clinically actionable decisions.
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Affiliation(s)
- Sara Larivière
- Multimodal Imaging and Connectome Analysis Laboratory, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Andrea Bernasconi
- Neuroimaging of Epilepsy Laboratory, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Neda Bernasconi
- Neuroimaging of Epilepsy Laboratory, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Boris C Bernhardt
- Multimodal Imaging and Connectome Analysis Laboratory, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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16
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Shu T, Xiao X, Long Z, Zhang R. Reduced structural covariance connectivity of defaut mode network and salience network in MRI-normal focal epilepsy. Neuroreport 2020; 31:1289-1295. [PMID: 33165193 DOI: 10.1097/wnr.0000000000001541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neuroimaging studies have found altered functional connectivity of default mode network (DMN) and salience network (SN) in patients with focal epilepsy (FE). However, the structural basis underlying the functional connectivity disturbance in the patients is still unclear. Sixteen MRI-normal FE and 22 healthy controls were included in the current study. The T1 structural image of each participant was obtained. Seed-based structural covariance connectivity was employed to investigate changes of structural covariance connectivity of DMN and SN in FE patients. We further evaluated gray matter volume changes of brain areas showing altered structural connectivity in the patients. We found that patients with FE showed reduced connectivity of posterior cingulate cortex and left medial prefrontal cortex, hippocampus and orbitofrontal cortex, and reduced connectivity of right fronto-insula cortex with left insula, orbitofrontal cortex, opercum part of inferior frontal cortex and right medial prefrontal cortex compared with healthy controls. Moreover, those brain areas showing significant reduced structural covariance connectivity in patients with FE also had a loss of gray matter volume, indicating that reduced structural connectivity of DMN and SN might be associated with gray matter atrophy in the patients. Those results highlight the crucial role of DMN and SN in the pathology of patients with FE, and provided structural basis for the functional disturbance of the two networks in this disease.
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Affiliation(s)
- Ting Shu
- Medical Imaging Center, Second Affiliated Hospital of Nanchang University, Nanchang
| | - Xinlan Xiao
- Medical Imaging Center, Second Affiliated Hospital of Nanchang University, Nanchang
| | - Zhiliang Long
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, China
| | - Ran Zhang
- Medical Imaging Center, Second Affiliated Hospital of Nanchang University, Nanchang
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17
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Yang P, Qin Y, Zhu Y, Li F, Xia SS, Zhou B, Wang Q, Lu J, Li L, Huang HY. Chaihu-Longgu-Muli decoction relieves epileptic symptoms by improving autophagy in hippocampal neurons. JOURNAL OF ETHNOPHARMACOLOGY 2020; 259:112990. [PMID: 32442588 DOI: 10.1016/j.jep.2020.112990] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 05/05/2020] [Accepted: 05/16/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Chaihu-Longgu-Muli decoction (CLMD) is a well-known ancient formula in traditional Chinese medicine (TCM) to relieve disorder, clear away heat, tranquilize the mind and allay excitement. It has been used for the therapy of neuropsychiatric disorders such as epilepsy, dementia, insomnia, anxiety, and depression for several centuries in China. AIM OF THE STUDY This paper is based on the assumption that the mechanism by which CLMD relieves epileptic symptoms in rats is associated with improving autophagy. Several experimental methods are designed to testify the hypothesis. MATERIALS AND METHODS The lithium-pilocarpine-induced epilepsy model was established in rats. The seizure frequency was recorded. Morphology and number of autophagosomes in hippocampal dentate gyrus was detected with a transmission electron microscope (TEM). Expression of Beclin-1, microtubule-associated proteins 1A/1B light chain 3 (LC3), and mammalian target of rapamycin (mTOR) in dentate gyrus was measured by immunofluorescence assay, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western-blotting. RESULTS CLMD could significantly relieve the seizure frequency and improve autophagy in hippocampal dentate gyrus. Meanwhile, the level of Beclin-1 and LC3B decreased significantly, while mTOR increased remarkably after medical intervention. CONCLUSIONS CLMD could improve autophagy in hippocampal dentate gyrus due to epilepsy, especially at high dose. The mechanism may be related to upregulated expression of mTOR and downregulated expression of Beclin-1 and LC3B.
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Affiliation(s)
- Ping Yang
- Department of Psychiatry, Hunan Brain Hospital, Clinical Medical School of Hunan University of Chinese Medicine, NO.427, Middle Furong Road, Changsha, Hunan Province, 410007, China; Provincial Key Laboratory of TCM Diagnostics, Hunan University of Chinese Medicine, NO.300, Xueshi Road, Changsha, Hunan Province, 410208, China
| | - You Qin
- Institute of Chinese Materia Medica, Hunan Academy of Chinese Medicine, NO. 8, Yuehua Road, Changsha, Hunan Province, 410013, China
| | - Yong Zhu
- Department of Psychiatry, Hunan Brain Hospital, Clinical Medical School of Hunan University of Chinese Medicine, NO.427, Middle Furong Road, Changsha, Hunan Province, 410007, China
| | - Feng Li
- Provincial Key Laboratory of TCM Diagnostics, Hunan University of Chinese Medicine, NO.300, Xueshi Road, Changsha, Hunan Province, 410208, China; School of Dentistry, University of California Los Angeles, 405 Hilgard Ave, Los Angeles, CA, 90095, USA
| | - Shuai-Shuai Xia
- Provincial Key Laboratory of TCM Diagnostics, Hunan University of Chinese Medicine, NO.300, Xueshi Road, Changsha, Hunan Province, 410208, China
| | - Bin Zhou
- Department of Psychiatry, Hunan Brain Hospital, Clinical Medical School of Hunan University of Chinese Medicine, NO.427, Middle Furong Road, Changsha, Hunan Province, 410007, China
| | - Qin Wang
- Department of Psychiatry, Hunan Brain Hospital, Clinical Medical School of Hunan University of Chinese Medicine, NO.427, Middle Furong Road, Changsha, Hunan Province, 410007, China
| | - Jun Lu
- Department of Psychiatry, Hunan Brain Hospital, Clinical Medical School of Hunan University of Chinese Medicine, NO.427, Middle Furong Road, Changsha, Hunan Province, 410007, China
| | - Liang Li
- Provincial Key Laboratory of TCM Diagnostics, Hunan University of Chinese Medicine, NO.300, Xueshi Road, Changsha, Hunan Province, 410208, China.
| | - Hui-Yong Huang
- Provincial Key Laboratory of TCM Diagnostics, Hunan University of Chinese Medicine, NO.300, Xueshi Road, Changsha, Hunan Province, 410208, China.
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18
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Mnemonic discrimination in patients with unilateral mesial temporal lobe epilepsy relates to similarity and number of events stored in memory. Neurobiol Learn Mem 2020; 169:107177. [DOI: 10.1016/j.nlm.2020.107177] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 01/24/2020] [Accepted: 02/05/2020] [Indexed: 01/15/2023]
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19
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Tan L, Chen Y, Wu W, Liu C, Fu Y, He J, Zhang M, Wang G, Wang K, Long H, Xiao W, Xiao B, Long L. Impaired Cognitive Abilities in Siblings of Patients with Temporal Lobe Epilepsy. Neuropsychiatr Dis Treat 2020; 16:3071-3079. [PMID: 33363375 PMCID: PMC7752648 DOI: 10.2147/ndt.s258074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Patients with temporal lobe epilepsy (TLE) are at high risk of cognitive impairment. In addition to persistent seizures and antiepileptic drugs (AEDs), genetic factors also play an important role in the progression of cognitive deficits in TLE patients. Defining a cognitive endophenotype for TLE can provide information on the risk of cognitive impairment in patients. This study investigated the cognitive endophenotype of TLE by comparing neuropsychological function between patients with TLE, their unaffected siblings, and healthy control subjects. PATIENTS AND METHODS A total of 46 patients with TLE, 26 siblings, and 33 control subjects were recruited. Cognitive function (ie, general cognition, short- and long-term memory, attention, visuospatial and executive functions, and working memory) was assessed with a battery of neuropsychological tests. Differences between groups were evaluated by analysis of covariance, with age and years of education as covariates. The Kruskal-Wallis test was used to evaluate data that did not satisfy the homogeneity of variance assumption. Pairwise comparisons were adjusted by Bonferroni correction, with a significance threshold of P<0.05. RESULTS Patients with TLE showed deficits in the information test (P<0.001), arithmetic test (P=0.003), digit symbol substitution test (P=0.001), block design test (BDT; P=0.005), and backward digit span test (P=0.001) and took a longer time to complete the Hayling test Part A (P=0.011) compared to controls. Left TLE patients tended to have worse executive function test scores than right TLE patients. The siblings of TLE patients showed deficits in the BDT (P=0.006, Bonferroni-corrected) relative to controls. CONCLUSION Patients with TLE exhibit cognitive impairment. Executive function is worse in patients with left TLE than in those with right TLE. Siblings show impaired visuospatial function relative to controls. Thus, cognitive deficits in TLE patients have a genetic component and are independent of seizures or AED use.
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Affiliation(s)
- Langzi Tan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Yayu Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Wenyue Wu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Chaorong Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Yujiao Fu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Jialinzi He
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Min Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Ge Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Kangrun Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Hongyu Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Wenbiao Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
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20
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Stark SM, Kirwan CB, Stark CEL. Mnemonic Similarity Task: A Tool for Assessing Hippocampal Integrity. Trends Cogn Sci 2019; 23:938-951. [PMID: 31597601 DOI: 10.1016/j.tics.2019.08.003] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 12/25/2022]
Abstract
The hippocampus is critical for learning and memory, relying in part on pattern separation processes supported by the dentate gyrus (DG) to prevent interference from overlapping memory representations. In 2007, we designed the Mnemonic Similarity Task (MST), a modified object recognition memory task, to be highly sensitive to hippocampal function by placing strong demands on pattern separation. The MST is now a widely used behavioral task, repeatedly shown to be sensitive to age-related memory decline, hippocampal connectivity, and hippocampal function, with specificity to the DG. Here, we review the utility of the MST, its relationship to hippocampal function, its utility in detecting hippocampal-based memory alterations across the lifespan, and impairments associated with clinical pathology from a variety of disorders.
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Affiliation(s)
- Shauna M Stark
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - C Brock Kirwan
- Department of Psychology, Neuroscience Center, Brigham Young University, Provo, UT, USA
| | - Craig E L Stark
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA.
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21
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Nobis L, Manohar SG, Smith SM, Alfaro-Almagro F, Jenkinson M, Mackay CE, Husain M. Hippocampal volume across age: Nomograms derived from over 19,700 people in UK Biobank. Neuroimage Clin 2019; 23:101904. [PMID: 31254939 PMCID: PMC6603440 DOI: 10.1016/j.nicl.2019.101904] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 06/13/2019] [Accepted: 06/16/2019] [Indexed: 12/18/2022]
Abstract
Measurement of hippocampal volume has proven useful to diagnose and track progression in several brain disorders, most notably in Alzheimer's disease (AD). For example, an objective evaluation of a patient's hippocampal volume status may provide important information that can assist diagnosis or risk stratification of AD. However, clinicians and researchers require access to age-related normative percentiles to reliably categorise a patient's hippocampal volume as being pathologically small. Here we analysed effects of age, sex, and hemisphere on the hippocampus and neighbouring temporal lobe volumes, in 19,793 generally healthy participants in the UK Biobank. A key finding of the current study is a significant acceleration in the rate of hippocampal volume loss in middle age, more pronounced in females than in males. In this report, we provide normative values for hippocampal and total grey matter volume as a function of age for reference in clinical and research settings. These normative values may be used in combination with our online, automated percentile estimation tool to provide a rapid, objective evaluation of an individual's hippocampal volume status. The data provide a large-scale normative database to facilitate easy age-adjusted determination of where an individual hippocampal and temporal lobe volume lies within the normal distribution.
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Affiliation(s)
- Lisa Nobis
- Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.
| | - Sanjay G Manohar
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Stephen M Smith
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Health NHS Foundation Trust, Oxford, UK
| | - Fidel Alfaro-Almagro
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Health NHS Foundation Trust, Oxford, UK
| | - Mark Jenkinson
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Health NHS Foundation Trust, Oxford, UK
| | - Clare E Mackay
- Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK; Oxford Health NHS Foundation Trust, Oxford, UK
| | - Masud Husain
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Department of Experimental Psychology, University of Oxford, Oxford, UK; Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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22
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Williams ME, Graves LV, DeJesus SY, Holden HM, DeFord NE, Gilbert PE. Spatial memory ability during middle age may depend on level of spatial similarity. ACTA ACUST UNITED AC 2018; 26:20-23. [PMID: 30559116 PMCID: PMC6298540 DOI: 10.1101/lm.048280.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/29/2018] [Indexed: 12/26/2022]
Abstract
Spatial memory impairment is well documented in old age; however, less is known about spatial memory during middle age. We examined the performance of healthy young, middle-aged, and older adults on a spatial memory task with varying levels of spatial similarity (distance). On low similarity trials, young adults significantly outperformed middle-aged adults, who significantly outperformed older adults (Ps < 0.05). On high similarity trials, young adults significantly outperformed middle-aged and older adults (Ps < 0.05); however, middle-aged and older adults did not differ. Subtle age-related changes in spatial memory may emerge during middle age, particularly when spatial similarity is high.
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Affiliation(s)
- McKenna E Williams
- Department of Psychology, San Diego State University, San Diego, California 92182, USA
| | - Lisa V Graves
- Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California San Diego, San Diego/La Jolla, California 92120, USA
| | | | - Heather M Holden
- Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California San Diego, San Diego/La Jolla, California 92120, USA
| | - Nicole E DeFord
- Department of Psychology, San Diego State University, San Diego, California 92182, USA
| | - Paul E Gilbert
- Department of Psychology, San Diego State University, San Diego, California 92182, USA.,Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California San Diego, San Diego/La Jolla, California 92120, USA
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23
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Kumar J, Solaiman A, Mahakkanukrauh P, Mohamed R, Das S. Sleep Related Epilepsy and Pharmacotherapy: An Insight. Front Pharmacol 2018; 9:1088. [PMID: 30319421 PMCID: PMC6171479 DOI: 10.3389/fphar.2018.01088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/07/2018] [Indexed: 01/26/2023] Open
Abstract
In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.
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Affiliation(s)
- Jaya Kumar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Amro Solaiman
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Pasuk Mahakkanukrauh
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Excellence Centre in Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Rashidi Mohamed
- Department of Familty Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Srijit Das
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
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