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Foster SL, Breukelaar IA, Ekanayake K, Lewis S, Korgaonkar MS. Functional Magnetic Resonance Imaging of the Amygdala and Subregions at 3 Tesla: A Scoping Review. J Magn Reson Imaging 2024; 59:361-375. [PMID: 37352130 DOI: 10.1002/jmri.28836] [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: 03/05/2023] [Revised: 05/18/2023] [Accepted: 05/18/2023] [Indexed: 06/25/2023] Open
Abstract
The amygdalae are a pair of small brain structures, each of which is composed of three main subregions and whose function is implicated in neuropsychiatric conditions. Functional Magnetic Resonance Imaging (fMRI) has been utilized extensively in investigation of amygdala activation and functional connectivity (FC) with most clinical research sites now utilizing 3 Tesla (3T) MR systems. However, accurate imaging and analysis remains challenging not just due to the small size of the amygdala, but also its location deep in the temporal lobe. Selection of imaging parameters can significantly impact data quality with implications for the accuracy of study results and validity of conclusions. Wide variation exists in acquisition protocols with spatial resolution of some protocols suboptimal for accurate assessment of the amygdala as a whole, and for measuring activation and FC of the three main subregions, each of which contains multiple nuclei with specialized roles. The primary objective of this scoping review is to provide a broad overview of 3T fMRI protocols in use to image the activation and FC of the amygdala with particular reference to spatial resolution. The secondary objective is to provide context for a discussion culminating in recommendations for a standardized protocol for imaging activation of the amygdala and its subregions. As the advantages of big data and protocol harmonization in imaging become more apparent so, too, do the disadvantages of data heterogeneity. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Sheryl L Foster
- Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Department of Radiology, Westmead Hospital, Westmead, New South Wales, Australia
| | - Isabella A Breukelaar
- Brain Dynamics Centre, The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
| | - Kanchana Ekanayake
- University Library, The University of Sydney, Sydney, New South Wales, Australia
| | - Sarah Lewis
- Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
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Peek SI, Twele F, Meller S, Packer RMA, Volk HA. Epilepsy is more than a simple seizure disorder: Causal relationships between epilepsy and its comorbidities. Vet J 2024; 303:106061. [PMID: 38123062 DOI: 10.1016/j.tvjl.2023.106061] [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: 06/05/2021] [Revised: 11/10/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
This review draws connections between the pathogenesis of canine epilepsy and its most commonly recognised comorbidities: cognitive impairment (CI), attention deficit hyperactivity disorder (ADHD)-like behaviour, fear and anxiety. Uni/bidirectional causalities and the possibility of a common aetiology triggering both epilepsy and the associated diseases are considered. Research on this topic is sparse in dogs, so information has been gathered and assessed from human and laboratory animal studies. Anatomical structures, functional connections, disrupted neurotransmission and neuroinflammatory processes collectively serve as a common foundation for epilepsy and its comorbidities. Specific anatomical structures, especially parts of the limbic system, such as the amygdala and the hippocampus, are involved in generating seizures, as well as cognitive- and behavioural disorders. Furthermore, disturbances in inhibitory and excitatory neurotransmission influence neuronal excitability and networks, leading to underlying brain dysfunction. Functional magnetic resonance imaging (fMRI), interictal epileptiform discharges (IEDs), and electroencephalography (EEG) have demonstrated functional brain connections that are related to the emergence of both epilepsy and its various comorbidities. Neuroinflammatory processes can either cause or be a consequence of seizures, and inflammatory mediators, oxidative stress and mitochondrial dysfunction, can equally evoke mood disorders. The extensive relationships contributing to the development and progression of seizures and comorbid cognitive and behavioural conditions illustrate the complexity of the disease that is epilepsy.
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Affiliation(s)
- Saskia I Peek
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany
| | - Friederike Twele
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany
| | - Sebastian Meller
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany
| | | | - Holger A Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany.
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McDonald CR. A journey with Steve Schachter as Editor-in-Chief: From first submission to fiber tract cover model. Epilepsy Behav 2022; 137:108807. [PMID: 36463038 DOI: 10.1016/j.yebeh.2022.108807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 06/19/2022] [Indexed: 12/05/2022]
Affiliation(s)
- Carrie R McDonald
- Center for Multimodal Imaging and Genetics, University of California, San Diego, United States
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Nair KP, Salaka RJ, Srikumar BN, Kutty BM, Rao BSS. Enriched environment rescues impaired sleep-wake architecture and abnormal neural dynamics in chronic epileptic rats. Neuroscience 2022; 495:97-114. [DOI: 10.1016/j.neuroscience.2022.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 11/16/2022]
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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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Boschi A, Brofiga M, Massobrio P. Thresholding Functional Connectivity Matrices to Recover the Topological Properties of Large-Scale Neuronal Networks. Front Neurosci 2021; 15:705103. [PMID: 34483826 PMCID: PMC8415479 DOI: 10.3389/fnins.2021.705103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/20/2021] [Indexed: 12/24/2022] Open
Abstract
The identification of the organization principles on the basis of the brain connectivity can be performed in terms of structural (i.e., morphological), functional (i.e., statistical), or effective (i.e., causal) connectivity. If structural connectivity is based on the detection of the morphological (synaptically mediated) links among neurons, functional and effective relationships derive from the recording of the patterns of electrophysiological activity (e.g., spikes, local field potentials). Correlation or information theory-based algorithms are typical routes pursued to find statistical dependencies and to build a functional connectivity matrix. As long as the matrix collects the possible associations among the network nodes, each interaction between the neuron i and j is different from zero, even though there was no morphological, statistical or causal connection between them. Hence, it becomes essential to find and identify only the significant functional connections that are predictive of the structural ones. For this reason, a robust, fast, and automatized procedure should be implemented to discard the “noisy” connections. In this work, we present a Double Threshold (DDT) algorithm based on the definition of two statistical thresholds. The main goal is not to lose weak but significant links, whose arbitrary exclusion could generate functional networks with a too small number of connections and altered topological properties. The algorithm allows overcoming the limits of the simplest threshold-based methods in terms of precision and guaranteeing excellent computational performances compared to shuffling-based approaches. The presented DDT algorithm was compared with other methods proposed in the literature by using a benchmarking procedure based on synthetic data coming from the simulations of large-scale neuronal networks with different structural topologies.
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Affiliation(s)
- Alessio Boschi
- Department of Informatics, Bioengineering, Robotics, Systems Engineering (DIBRIS), University of Genova, Genova, Italy
| | - Martina Brofiga
- Department of Informatics, Bioengineering, Robotics, Systems Engineering (DIBRIS), University of Genova, Genova, Italy
| | - Paolo Massobrio
- Department of Informatics, Bioengineering, Robotics, Systems Engineering (DIBRIS), University of Genova, Genova, Italy.,National Institute for Nuclear Physics (INFN), Genova, Italy
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Balzekas I, Sladky V, Nejedly P, Brinkmann BH, Crepeau D, Mivalt F, Gregg NM, Pal Attia T, Marks VS, Wheeler L, Riccelli TE, Staab JP, Lundstrom BN, Miller KJ, Van Gompel J, Kremen V, Croarkin PE, Worrell GA. Invasive Electrophysiology for Circuit Discovery and Study of Comorbid Psychiatric Disorders in Patients With Epilepsy: Challenges, Opportunities, and Novel Technologies. Front Hum Neurosci 2021; 15:702605. [PMID: 34381344 PMCID: PMC8349989 DOI: 10.3389/fnhum.2021.702605] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/29/2021] [Indexed: 01/10/2023] Open
Abstract
Intracranial electroencephalographic (iEEG) recordings from patients with epilepsy provide distinct opportunities and novel data for the study of co-occurring psychiatric disorders. Comorbid psychiatric disorders are very common in drug-resistant epilepsy and their added complexity warrants careful consideration. In this review, we first discuss psychiatric comorbidities and symptoms in patients with epilepsy. We describe how epilepsy can potentially impact patient presentation and how these factors can be addressed in the experimental designs of studies focused on the electrophysiologic correlates of mood. Second, we review emerging technologies to integrate long-term iEEG recording with dense behavioral tracking in naturalistic environments. Third, we explore questions on how best to address the intersection between epilepsy and psychiatric comorbidities. Advances in ambulatory iEEG and long-term behavioral monitoring technologies will be instrumental in studying the intersection of seizures, epilepsy, psychiatric comorbidities, and their underlying circuitry.
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Affiliation(s)
- Irena Balzekas
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States
- Mayo Clinic Alix School of Medicine, Rochester, MN, United States
- Mayo Clinic Medical Scientist Training Program, Rochester, MN, United States
| | - Vladimir Sladky
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czechia
| | - Petr Nejedly
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- The Czech Academy of Sciences, Institute of Scientific Instruments, Brno, Czechia
| | - Benjamin H. Brinkmann
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Daniel Crepeau
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Filip Mivalt
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Faculty of Electrical Engineering and Communication, Department of Biomedical Engineering, Brno University of Technology, Brno, Czechia
| | - Nicholas M. Gregg
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Tal Pal Attia
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Victoria S. Marks
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States
| | - Lydia Wheeler
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States
- Mayo Clinic Alix School of Medicine, Rochester, MN, United States
| | - Tori E. Riccelli
- Mayo Clinic Alix School of Medicine, Rochester, MN, United States
| | - Jeffrey P. Staab
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, United States
- Department of Otorhinolaryngology, Mayo Clinic, Rochester, MN, United States
| | - Brian Nils Lundstrom
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Kai J. Miller
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States
| | - Jamie Van Gompel
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States
| | - Vaclav Kremen
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czechia
| | - Paul E. Croarkin
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, United States
| | - Gregory A. Worrell
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN, United States
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Scopolamine prevents aberrant mossy fiber sprouting and facilitates remission of epilepsy after brain injury. Neurobiol Dis 2021; 158:105446. [PMID: 34280524 DOI: 10.1016/j.nbd.2021.105446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 11/21/2022] Open
Abstract
Prevention or modification of acquired epilepsy in patients at risk is an urgent, yet unmet, clinical need. Following acute brain insults, there is an increased risk of mesial temporal lobe epilepsy (mTLE), which is often associated with debilitating comorbidities and reduced life expectancy. The latent period between brain injury and the onset of epilepsy may offer a therapeutic window for interfering with epileptogenesis. The pilocarpine model of mTLE is widely used in the search for novel antiepileptogenic treatments. Recent biochemical studies indicated that cholinergic mechanisms play a role in the epileptogenic alterations induced by status epilepticus (SE) in this and other models of mTLE, which prompted us to evaluate whether treatment with the muscarinic antagonist scopolamine during the latent period after SE is capable of preventing or modifying epilepsy and associated behavioral and cognitive alterations in female Sprague-Dawley rats. First, in silico pharmacokinetic modeling was used to select a dosing protocol by which M-receptor inhibitory brain levels of scopolamine are maintained during prolonged treatment. This protocol was verified by drug analysis in vivo. Rats were then treated twice daily with scopolamine over 17 days after SE, followed by drug wash-out and behavioral and video/EEG monitoring up to ~6 months after SE. Compared to vehicle controls, rats that were treated with scopolamine during the latent period exhibited a significantly lower incidence of spontaneous recurrent seizures during periods of intermittent recording in the chronic phase of epilepsy, less behavioral excitability, less cognitive impairment, and significantly reduced aberrant mossy fiber sprouting in the hippocampus. The present data may indicate that scopolamine exerts antiepileptogenic/disease-modifying activity in the lithium-pilocarpine rat model, possibly involving increased remission of epilepsy as a new mechanism of disease-modification. For evaluating the rigor of the present data, we envision a study that more thoroughly addresses the gender bias and video-EEG recording limitations of the present study.
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Qin Y, Tong X, Li W, Zhang L, Zhang Y, Li X, Yang J, Qin K, Lei D, Gong Q, Zhou D, An D. Divergent Anatomical Correlates and Functional Network Connectivity Patterns in Temporal Lobe Epilepsy with and Without Depression. Brain Topogr 2021; 34:525-536. [PMID: 33973138 DOI: 10.1007/s10548-021-00848-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 05/05/2021] [Indexed: 02/05/2023]
Abstract
Epilepsy and depression were proposed to facilitate each other reciprocally through common neurobiological anomalies, especially the prefrontal-limbic-subcortical abnormalities. Yet neuroimaging patterns of higher-order cognitive networks and neuroanatomical correlates were rarely compared in temporal lobe epilepsy patients with (TLE-D) and without depression (TLE-N). We collected T1-weighted structural and resting-state functional MRI data from 20 TLE-D, 31 TLE-N and 20 healthy controls (HCs) and performed analyses including hippocampal volume (HCV), cortical thickness, gray matter volume (GMV) and whole-brain functional network connectivity (FNC) across three groups. Imaging differences were related to clinical and psychological measurements. TLE-D demonstrated disrupted functional role of subcortical (SUB) and higher-order cognitive networks compared to TLE-N and HCs. In TLE-D, GMV in the right supplementary motor area (SMA) and FNC between the dorsal attention (DAN) and SUB were attenuated compared to TLE-N and HCs, FNC between SUB and the visual network (VIS) decreased compared to HCs. GMV in the right SMA was negatively correlated with depression severity and some symptoms. Combined, explicit emotion regulation may be impaired in TLE-D. Meanwhile, compared to HCs, TLE-N showed smaller HCVs, TLE-D and TLE-N showed smaller GMV in the medial orbital frontal gyrus and right hippocampus and hippocampal gyrus, possibly implying predisposition of epileptic activities to co-morbid depression. Our findings suggest distinct anatomical and FNC patterns in TLE-D and TLE-N. More than prefrontal-limbic-subcortical anomalies, disrupted higher-order cognitive network may contribute to depression in TLE, providing new potential treatment targets for depression and calling attention to relation between cognitive dysfunction and co-morbid depression.
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Affiliation(s)
- Yingjie Qin
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xin Tong
- Department of Neurology, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Wei Li
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Le Zhang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yingying Zhang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xiuli Li
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jing Yang
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Kun Qin
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Du Lei
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Qiyong Gong
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Dong Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Dongmei An
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
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Executive function and depressed mood are independently disruptive to health-related quality of life in pediatric temporal lobe epilepsy. Epilepsy Behav 2021; 115:107681. [PMID: 33360405 DOI: 10.1016/j.yebeh.2020.107681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/21/2020] [Accepted: 11/28/2020] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Youth with temporal lobe epilepsy (TLE) are at increased risk of depressive features and diminished health-related quality of life (HRQOL). To assist in the development of future behavioral interventions for youth with TLE, the current study explored potential pathways by which executive functioning (EF) and depressive features impinge upon HRQOL in the context of psychosocial and seizure-specific factors. METHODS Data included parental ratings on the Behavior Assessment System for Children (BASC-2), Behavior Rating Inventory of Executive Function (BRIEF), and the Quality of Life in Childhood Epilepsy (QOLCE) questionnaires for 82 children (Age = 11.99, SD = 3.80) with TLE. Observed path analysis was used to simultaneously investigate the determinants of HRQOL in pediatric TLE. Indirect effects were evaluated with bootstrap analyses. RESULTS Both executive dysfunction and depressive features were negatively linked to child HRQOL, and, furthermore, EF and HRQOL were indirectly connected by depressive features. In addition, depressive features were linked to lower EF, current antiepileptic drug (AED) regimen, and the presence of hippocampal sclerosis. Diminished EF was linked to parental psychiatric history and family stress; EF mediated the relationship of parental psychiatric history and family stress on both depressive features and diminished HRQOL. Finally, a more complicated AED regimen and higher HRQOL were indirectly connected by depressive features. CONCLUSION This study underscores the importance of child depressive features and EF along with environmental and epilepsy-specific factors on HRQOL in pediatric TLE.
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Elkommos S, Mula M. A systematic review of neuroimaging studies of depression in adults with epilepsy. Epilepsy Behav 2021; 115:107695. [PMID: 33348194 DOI: 10.1016/j.yebeh.2020.107695] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/03/2020] [Accepted: 12/03/2020] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Depression is a relatively common comorbidity in people with epilepsy with a lifetime history identified in 1 in 4 individuals. In this paper, we aimed to provide a systematic review of structural and functional brain region-specific group differences of adults with epilepsy and depression and to discuss existing evidence as compared to that in people with depression. METHODS We undertook a systematic review of neuroimaging studies of depression in adults with epilepsy through MEDLINE/PubMed, Embase and PsycInfo searches until June 2020. RESULTS A total of 44 studies were included in the qualitative synthesis: 21 on structural neuroimaging, 9 on functional, and 14 on pharmaco/metabolic neuroimaging. Almost all studies focused on temporal lobe epilepsy (TLE). Patterns of changes in the hippocampi and subcortical structures seem to be different from those reported in depression outside epilepsy. Cortical changes are grossly similar as well as the lack of any laterality effect. Serotonin dysfunction seems to be due to different mechanisms with reduced synaptic availability for depression in epilepsy as compared to reduced 5HT1 receptor density outside epilepsy. Depressive symptoms seem to correlate with a dysfunction in temporolimbic structures contralateral to the epileptogenic zone especially in patients with de novo postsurgical depression. CONCLUSIONS Depression, at least in TLE, seems to be associated with a different pattern of brain changes as compared to major depression, potentially supporting the notion of phenomenological peculiarities of depression in epilepsy.
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Affiliation(s)
- Samia Elkommos
- Atkinson Morley Regional Neuroscience Centre, St George's University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Marco Mula
- Atkinson Morley Regional Neuroscience Centre, St George's University Hospitals NHS Foundation Trust, London, United Kingdom; Institute of Medical and Biomedical Education, St George's University of London, United Kingdom.
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12
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Rivera Bonet CN, Hwang G, Hermann B, Struck AF, J Cook C, A Nair V, Mathis J, Allen L, Almane DN, Arkush K, Birn R, Conant LL, DeYoe EA, Felton E, Maganti R, Nencka A, Raghavan M, Shah U, Sosa VN, Ustine C, Prabhakaran V, Binder JR, Meyerand ME. Neuroticism in temporal lobe epilepsy is associated with altered limbic-frontal lobe resting-state functional connectivity. Epilepsy Behav 2020; 110:107172. [PMID: 32554180 PMCID: PMC7483612 DOI: 10.1016/j.yebeh.2020.107172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 11/18/2022]
Abstract
Neuroticism, a core personality trait characterized by a tendency towards experiencing negative affect, has been reported to be higher in people with temporal lobe epilepsy (TLE) compared with healthy individuals. Neuroticism is a known predictor of depression and anxiety, which also occur more frequently in people with TLE. The purpose of this study was to identify abnormalities in whole-brain resting-state functional connectivity in relation to neuroticism in people with TLE and to determine the degree of unique versus shared patterns of abnormal connectivity in relation to elevated symptoms of depression and anxiety. Ninety-three individuals with TLE (55 females) and 40 healthy controls (18 females) from the Epilepsy Connectome Project (ECP) completed measures of neuroticism, depression, and anxiety, which were all significantly higher in people with TLE compared with controls. Resting-state functional connectivity was compared between controls and groups with TLE with high and low neuroticism using analysis of variance (ANOVA) and t-test. In secondary analyses, the same analytics were performed using measures of depression and anxiety and the unique variance in resting-state connectivity associated with neuroticism independent of symptoms of depression and anxiety identified. Increased neuroticism was significantly associated with hyposynchrony between the right hippocampus and Brodmann area (BA) 9 (region of prefrontal cortex (PFC)) (p < 0.005), representing a unique relationship independent of symptoms of depression and anxiety. Hyposynchrony of connection between the right hippocampus and BA47 (anterior frontal operculum) was associated with high neuroticism and with higher depression and anxiety scores (p < 0.05), making it a shared abnormal connection for the three measures. In conclusion, increased neuroticism exhibits both unique and shared patterns of abnormal functional connectivity with depression and anxiety symptoms between regions of the mesial temporal and frontal lobe.
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Affiliation(s)
| | - Gyujoon Hwang
- Department of Medical Physics, University of Wisconsin-Madison, United States of America
| | - Bruce Hermann
- Department of Neurology, University of Wisconsin-Madison, United States of America
| | - Aaron F Struck
- Department of Neurology, University of Wisconsin-Madison, United States of America
| | - Cole J Cook
- Department of Medical Physics, University of Wisconsin-Madison, United States of America
| | - Veena A Nair
- Department of Radiology, University of Wisconsin-Madison, United States of America
| | - Jedidiah Mathis
- Department of Radiology Froedtert & Medical College of Wisconsin, United States of America
| | - Linda Allen
- Department of Neurology, Medical College of Wisconsin, United States of America
| | - Dace N Almane
- Department of Neurology, University of Wisconsin-Madison, United States of America
| | - Karina Arkush
- Neuroscience Innovation Institute, Aurora St. Luke's Medical Center, United States of America
| | - Rasmus Birn
- Neuroscience Training Program, University of Wisconsin-Madison, United States of America; Department of Medical Physics, University of Wisconsin-Madison, United States of America; Department of Psychiatry, University of Wisconsin-Madison, United States of America
| | - Lisa L Conant
- Department of Neurology, Medical College of Wisconsin, United States of America
| | - Edgar A DeYoe
- Department of Radiology Froedtert & Medical College of Wisconsin, United States of America; Department of Biophysics, Medical College of Wisconsin, United States of America
| | - Elizabeth Felton
- Department of Neurology, University of Wisconsin-Madison, United States of America
| | - Rama Maganti
- Department of Neurology, University of Wisconsin-Madison, United States of America
| | - Andrew Nencka
- Department of Radiology Froedtert & Medical College of Wisconsin, United States of America
| | - Manoj Raghavan
- Department of Neurology, Medical College of Wisconsin, United States of America
| | - Umang Shah
- Neuroscience Innovation Institute, Aurora St. Luke's Medical Center, United States of America
| | - Veronica N Sosa
- Neuroscience Innovation Institute, Aurora St. Luke's Medical Center, United States of America
| | - Candida Ustine
- Department of Neurology, Medical College of Wisconsin, United States of America
| | - Vivek Prabhakaran
- Neuroscience Training Program, University of Wisconsin-Madison, United States of America; Department of Neurology, University of Wisconsin-Madison, United States of America; Department of Radiology, University of Wisconsin-Madison, United States of America
| | - Jeffrey R Binder
- Department of Neurology, Medical College of Wisconsin, United States of America; Department of Biophysics, Medical College of Wisconsin, United States of America
| | - Mary E Meyerand
- Neuroscience Training Program, University of Wisconsin-Madison, United States of America; Department of Medical Physics, University of Wisconsin-Madison, United States of America; Department of Radiology, University of Wisconsin-Madison, United States of America
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13
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Abstract
PURPOSE OF REVIEW Depression and anxiety substantially contribute to interictal disability in patients with epilepsy (PWE). This review summarizes current studies that shed light on mechanisms of comorbidity. RECENT FINDINGS Mounting epidemiological data implicate shared risk factors for anxiety/depression and seizure propensity, but these remain largely elusive and probably vary by epilepsy type. Within PWE, these symptoms appear to be associated with unique genetic, neuropathological, and connectivity profiles. Temporal lobe epilepsy has received enormous emphasis particularly in preclinical studies of comorbidity, where candidate neurobiological mechanisms underlying bidirectionality have been tested without psychopharmacological confounds. Depression and anxiety in epilepsy reflect dysfunction within broadly distributed limbic networks that may be the cause or consequence of epileptogenesis. In refractory epilepsy, seizures and/or certain anticonvulsants may distort central emotional homeostatic mechanisms that perpetually raise seizure risk. Developing future safe and effective combined anticonvulsant-antidepressant treatments will require a detailed understanding of anatomical and molecular nodes that pleiotropically enhance seizure risk and negatively alter emotionality.
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Affiliation(s)
- Vaishnav Krishnan
- Departments of Neurology, Neuroscience and Psychiatry & Behavioral Sciences, Baylor Comprehensive Epilepsy Center, Baylor College of Medicine, One Baylor Plaza St., MS: NB302, Houston, TX, 77030, USA.
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14
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Ren Y, Pan L, Du X, Li X, Hou Y, Bao J, Song Y. Theta oscillation and functional connectivity alterations related to executive control in temporal lobe epilepsy with comorbid depression. Clin Neurophysiol 2020; 131:1599-1609. [DOI: 10.1016/j.clinph.2020.03.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/01/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022]
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15
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Characterizing the gradients of structural covariance in the human hippocampus. Neuroimage 2020; 218:116972. [PMID: 32454206 DOI: 10.1016/j.neuroimage.2020.116972] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/29/2020] [Accepted: 05/17/2020] [Indexed: 11/23/2022] Open
Abstract
The hippocampus is a plastic brain structure that has been associated with a range of behavioral aspects but also shows vulnerability to the most frequent neurocognitive diseases. Different aspects of its organization have been revealed by studies probing its different neurobiological properties. In particular, histological work has shown a pattern of differentiation along the proximal-distal dimension, while studies examining functional properties and large-scale functional integration have primarily highlighted a pattern of differentiation along the anterior-posterior dimension. To better understand how these organizational dimensions underlie the pattern of structural covariance (SC) in the human hippocampus, we here applied a non-linear decomposition approach, disentangling the major modes of variation, to the pattern of gray matter volume correlation of hippocampus voxels with the rest of the brain in a sample of 377 healthy young adults. We additionally investigated the consistency of the derived gradients in an independent sample of life-span adults and also examined the relationships between these major modes of variations and the patterns derived from microstructure and functional connectivity mapping. Our results showed that similar major modes of SC-variability are identified across the two independent datasets. The major dimension of variation found in SC runs along the hippocampal anterior-posterior axis and followed closely the principal dimension of functional differentiation, suggesting an influence of network level interaction in this major mode of morphological variability. The second main mode of variability in the SC showed a gradient along the dorsal-ventral axis, and was moderately related to variability in hippocampal microstructural properties. Thus our results depicting relatively reliable patterns of SC-variability within the hippocampus show an interplay between the already known organizational principles on the pattern of variability in hippocampus' macrostructural properties. This study hence provides a first insight on the underlying organizational forces generating different co-plastic modes within the human hippocampus that may, in turn, help to better understand different vulnerability patterns of this crucial structure in different neurological and psychiatric diseases.
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16
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Chang BS, Krishnan V, Dulla CG, Jette N, Marsh ED, Dacks PA, Whittemore V, Poduri A. Epilepsy Benchmarks Area I: Understanding the Causes of the Epilepsies and Epilepsy-Related Neurologic, Psychiatric, and Somatic Conditions. Epilepsy Curr 2020; 20:5S-13S. [PMID: 31965828 PMCID: PMC7031801 DOI: 10.1177/1535759719895280] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The 2014 NINDS Benchmarks for Epilepsy Research included area I: Understand the causes of the epilepsies and epilepsy-related neurologic, psychiatric, and somatic conditions. In preparation for the 2020 Curing Epilepsies Conference, where the Benchmarks will be revised, this review will cover scientific progress toward that Benchmark, with emphasize on studies since 2016.
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Affiliation(s)
- Bernard S Chang
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Vaishnav Krishnan
- Departments of Neurology, Neuroscience and Psychiatry & Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Chris G Dulla
- Department of Neuroscience, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, USA
| | - Nathalie Jette
- Department of Neurology, Icahn School of Medicine at Mt. Sinai, New York, NY, USA.,Department of Population Health Science and Policy, Icahn School of Medicine at Mt. Sinai, New York, NY, USA
| | - Eric D Marsh
- Department of Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | | | - Vicky Whittemore
- Division of Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MA, USA
| | - Annapurna Poduri
- Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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17
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Zhou B, An D, Xiao F, Niu R, Li W, Li W, Tong X, Kemp GJ, Zhou D, Gong Q, Lei D. Machine learning for detecting mesial temporal lobe epilepsy by structural and functional neuroimaging. Front Med 2020; 14:630-641. [PMID: 31912429 DOI: 10.1007/s11684-019-0718-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/07/2019] [Indexed: 02/04/2023]
Abstract
Mesial temporal lobe epilepsy (mTLE), the most common type of focal epilepsy, is associated with functional and structural brain alterations. Machine learning (ML) techniques have been successfully used in discriminating mTLE from healthy controls. However, either functional or structural neuroimaging data are mostly used separately as input, and the opportunity to combine both has not been exploited yet. We conducted a multimodal ML study based on functional and structural neuroimaging measures. We enrolled 37 patients with left mTLE, 37 patients with right mTLE, and 74 healthy controls and trained a support vector ML model to distinguish them by using each measure and the combinations of the measures. For each single measure, we obtained a mean accuracy of 74% and 69% for discriminating left mTLE and right mTLE from controls, respectively, and 64% when all patients were combined. We achieved an accuracy of 78% by integrating functional data and 79% by integrating structural data for left mTLE, and the highest accuracy of 84% was obtained when all functional and structural measures were combined. These findings suggest that combining multimodal measures within a single model is a promising direction for improving the classification of individual patients with mTLE.
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Affiliation(s)
- Baiwan Zhou
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Dongmei An
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Fenglai Xiao
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, 610041, China.,Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1E 6BT, UK
| | - Running Niu
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Wenbin Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Wei Li
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Xin Tong
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Graham J Kemp
- Institute of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L9 7AL, UK
| | - Dong Zhou
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, 610041, China.
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China.,Department of Psychology, School of Public Administration, Sichuan University, Chengdu, 610041, China
| | - Du Lei
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China. .,Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK. .,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, 45219, USA.
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18
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Jiang Y, Liu DF, Zhang X, Liu HG, Zhang JG. Microstructure and functional connectivity-based evidence for memory-related regional impairments in the brains of pilocarpine-treated rats. Brain Res Bull 2019; 154:127-134. [PMID: 31756422 DOI: 10.1016/j.brainresbull.2019.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/09/2019] [Accepted: 11/17/2019] [Indexed: 12/21/2022]
Abstract
Patients with temporal lobe epilepsy (TLE) frequently suffer from memory disorders, and the pathological changes show widespread regional impairments in the brain. In lithium-pilocarpine (LIP)-treated rats with TLE, an abnormal hippocampal microstructure and functional connectivity have been observed. However, changes in other brain regions are still unclear. In the present study, diffusion tensor imaging and functional magnetic resonance imaging (MRI) signals were collected in LIP-TLE rats and controls using a 7.0 T MRI. Microstructural parameters and functional connectivity were calculated among regions of interest (ROIs), including the bilateral prefrontal cortex, amygdala, hippocampus and entorhinal cortex. A correlation analysis was further performed between the neuroimaging results and the behavioral performance in the novel object and novel location memory tests. In our results, TLE rats showed increased fractional anisotropy (FA) values in the hippocampus and decreased FA values in the amygdala and entorhinal cortex. In addition, decreased functional connectivity between the amygdala and the CA3, and increased connectivity between the prefrontal cortex and the CA1 were observed in the TLE rats compared to control rats. Moreover, FA values in the amygdala, the hippocampus and the entorhinal cortex, as well as the amygdala-CA3 and the prefrontal-CA1 connectivity correlated with the memory performance. Based on our results, both the microstructure and functional connections were impaired in memory-related brain regions of LIP-TLE rats. Furthermore, the abnormal changes in the microstructure and functional connectivity were related to behavioral deficits in object and location memory.
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Affiliation(s)
- Yin Jiang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China.
| | - De-Feng Liu
- Department of Functional Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xin Zhang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China
| | - Huan-Guang Liu
- Department of Functional Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jian-Guo Zhang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China; Department of Functional Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
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19
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Aberrant topological organization of the default mode network in temporal lobe epilepsy revealed by graph-theoretical analysis. Neurosci Lett 2019; 708:134351. [DOI: 10.1016/j.neulet.2019.134351] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/31/2019] [Accepted: 06/22/2019] [Indexed: 12/16/2022]
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20
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Zhang C, Zhang H, Xu K, Yang H, Liu C, Yu T, Chen N, Li K. Impaired prefrontal cortex-thalamus pathway in intractable temporal lobe epilepsy with aberrant executive control function: MRI evidence. Clin Neurophysiol 2019; 130:484-490. [DOI: 10.1016/j.clinph.2018.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/19/2018] [Accepted: 12/16/2018] [Indexed: 01/03/2023]
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21
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Paudel YN, Shaikh MF, Shah S, Kumari Y, Othman I. Role of inflammation in epilepsy and neurobehavioral comorbidities: Implication for therapy. Eur J Pharmacol 2018; 837:145-155. [PMID: 30125565 DOI: 10.1016/j.ejphar.2018.08.020] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 02/07/2023]
Abstract
Epilepsy is a devastating condition affecting around 70 million people worldwide. Moreover, the quality of life of people with epilepsy (PWE) is worsened by a series of comorbidities. The neurobehavioral comorbidities discussed herein share a reciprocal and complex relationship with epilepsy, which ultimately complicates the treatment process in PWE. Understanding the mechanistic pathway by which these comorbidities are associated with epilepsy might be instrumental in developing therapeutic interventions. Inflammatory cytokine signaling in the brain regulates important brain functions including neurotransmitter metabolism, neuroendocrine function, synaptic plasticity, dopaminergic transmission, the kynurenine pathway, and affects neurogenesis as well as the neural circuitry of moods. In this review, we hypothesize that the complex relationship between epilepsy and its related comorbidities (cognitive impairment, depression, anxiety, autism, and schizophrenia) can be unraveled through the inflammatory mechanism that plays a prominent role in all these individual conditions. An ample amount of evidence is available reporting the role of inflammation in epilepsy and all individual comorbid condition but their complex relationship with epilepsy has not yet been explored through the prospective of inflammatory pathway. Our review suggests that epilepsy and its neurobehavioral comorbidities are associated with elevated levels of several key inflammatory markers. This review also sheds light on the mechanistic association between epilepsy and its neurobehavioral comorbidities. Moreover, we analyzed several anti-inflammatory therapies available for epilepsy and its neurobehavioral comorbidities. We suggest, these anti-inflammatory therapies might be a possible intervention and could be a promising strategy for preventing epileptogenesis and its related neurobehavioral comorbidities.
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Affiliation(s)
- Yam Nath Paudel
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia.
| | - Sadia Shah
- Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India
| | - Yatinesh Kumari
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
| | - Iekhsan Othman
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
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22
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Executive Dysfunction and Depression in Pediatric Temporal Lobe Epilepsy: The Contribution of Hippocampal Sclerosis and Psychosocial Factors. J Int Neuropsychol Soc 2018; 24:606-616. [PMID: 29573759 DOI: 10.1017/s1355617718000140] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
OBJECTIVES Temporal lobe epilepsy (TLE) has been identified as a risk factor for increased depression features in children and adolescents; however, less is known regarding specific neurocognitive predictors of depression in this population above and beyond seizure-specific and sociodemographic factors. METHODS The study included 62 patients with TLE (64% male) aged 8 to 16 years (M=12.62; SD=2.26) who underwent comprehensive neuropsychological evaluation. RESULTS Correlation analyses revealed significant association between patient depression and WCST Total Perseverations, BRIEF Behavioral Regulation Index (BRI) and family stress. Perseverative errors on the WCST and the BRI were found to significantly predict depression features in youth with TLE. Patient performance on WCST was also found to fully mediate the significant relationship between hippocampal sclerosis (HS) and depression in pediatric TLE. Finally, logistic regression indicated HS in the presence of TLE was associated with a four-fold risk of clinically significant depression ratings. CONCLUSIONS The current findings offer strong support for the relationship between executive function (EF) and depression in pediatric TLE. Also, as HS is not modifiable, these findings suggest EF intervention may be a potential modality for improving health-related quality of life (HRQOL) in youth with TLE. (JINS, 2018, 24, 606-616).
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23
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Zhu X, He Z, Luo C, Qiu X, He S, Peng A, Zhang L, Chen L. Altered spontaneous brain activity in MRI-negative refractory temporal lobe epilepsy patients with major depressive disorder: A resting-state fMRI study. J Neurol Sci 2018; 386:29-35. [PMID: 29406962 DOI: 10.1016/j.jns.2018.01.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/31/2017] [Accepted: 01/09/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate alterations in spontaneous brain activity in MRI-negative refractory temporal lobe epilepsy patients with major depressive disorder using resting-state functional magnetic resonance imaging (RS-fMRI). METHODS Eighteen MRI-negative refractory temporal lobe epilepsy patients with major depressive disorder (PDD), 17 MRI-negative refractory temporal lobe epilepsy patients without major depressive disorder (nPDD), and 21 matched healthy controls (HC) were recruited from West China Hospital of SiChuan University from April 2016 to June 2017. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) and 17-item Hamilton Depression Rating Scale were employed to confirm the diagnosis of major depressive disorder and assess the severity of depression. All participants underwent RS-fMRI scans using a 3.0T MRI system. MRI data were compared and analyzed using the amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) to measure spontaneous brain activity. These two methods were both used to evaluate spontaneous cerebral activity. RESULTS The PDD group showed significantly altered spontaneous brain activity in the bilateral mesial prefrontal cortex, precuneus, angular gyrus, right parahippocampal gyrus, and right temporal pole. Meanwhile, compared with HC, the nPDD group demonstrated altered spontaneous brain activity in the temporal neocortex but no changes in mesial temporal structures. CONCLUSION The PDD group showed regional brain activity alterations in the prefrontal-limbic system and dysfunction of the default mode network. The underlying pathophysiology of PDD may be provided for further studies.
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Affiliation(s)
- Xi Zhu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhongqiong He
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China (UESTC), Chengdu, China
| | - Cheng Luo
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China (UESTC), Chengdu, China
| | - Xiangmiao Qiu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shixu He
- Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Anjiao Peng
- Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Lin Zhang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Lei Chen
- Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China.
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24
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Ravizza T, Onat FY, Brooks-Kayal AR, Depaulis A, Galanopoulou AS, Mazarati A, Numis AL, Sankar R, Friedman A. WONOEP appraisal: Biomarkers of epilepsy-associated comorbidities. Epilepsia 2016; 58:331-342. [PMID: 28035782 DOI: 10.1111/epi.13652] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2016] [Indexed: 01/04/2023]
Abstract
Neurologic and psychiatric comorbidities are common in patients with epilepsy. Diagnostic, predictive, and pharmacodynamic biomarkers of such comorbidities do not exist. They may share pathogenetic mechanisms with epileptogenesis/ictogenesis, and as such are an unmet clinical need. The objectives of the subgroup on biomarkers of comorbidities at the XIII Workshop on the Neurobiology of Epilepsy (WONOEP) were to present the state-of-the-art recent research findings in the field that highlighting potential biomarkers for comorbidities in epilepsy. We review recent progress in the field, including molecular, imaging, and genetic biomarkers of comorbidities as discussed during the WONOEP meeting on August 31-September 4, 2015, in Heybeliada Island (Istanbul, Turkey). We further highlight new directions and concepts from studies on comorbidities and potential new biomarkers for the prediction, diagnosis, and treatment of epilepsy-associated comorbidities. The activation of various molecular signaling pathways such as the "Janus Kinase/Signal Transducer and Activator of Transcription," "mammalian Target of Rapamycin," and oxidative stress have been shown to correlate with the presence and severity of subsequent cognitive abnormalities. Furthermore, dysfunction in serotonergic transmission, hyperactivity of the hypothalamic-pituitary-adrenocortical axis, the role of the inflammatory cytokines, and the contributions of genetic factors have all recently been regarded as relevant for understanding epilepsy-associated depression and cognitive deficits. Recent evidence supports the utility of imaging studies as potential biomarkers. The role of such biomarker may be far beyond the diagnosis of comorbidities, as accumulating clinical data indicate that comorbidities can predict epilepsy outcomes. Future research is required to reveal whether molecular changes in specific signaling pathways or advanced imaging techniques could be detected in the clinical settings and correlate with epilepsy-associated comorbidities. A reliable biomarker will allow a more accurate diagnosis and improved treatment of epilepsy-associated comorbidities.
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Affiliation(s)
- Teresa Ravizza
- Department of Neuroscience, IRCCS-"Mario Negri" Institute for Pharmacological Research, Milano, Italy
| | - Filiz Y Onat
- Department of Medical Pharmacology, Epilepsy Research Center, School of Medicine Marmara University, Istanbul, Turkey
| | - Amy R Brooks-Kayal
- Department of Pediatrics, Neurology and Pharmaceutical Sciences, Children's Hospital Colorado, University of Colorado Schools of Medicine and Pharmacy, Aurora, Colorado, U.S.A
| | | | - Aristea S Galanopoulou
- Laboratory of Developmental Neuroscience, Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, U.S.A.,Montefiore/Einstein Comprehensive Epilepsy Center, Montefiore Medical Center, Bronx, New York, U.S.A
| | - Andrey Mazarati
- Neurology Division, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Adam L Numis
- Neurology Division, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Raman Sankar
- Neurology Division, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Alon Friedman
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
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25
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Andrade-Machado R, Benjumea-Cuartas V. Temporal plus epilepsy: Anatomo-electroclinical subtypes. IRANIAN JOURNAL OF NEUROLOGY 2016; 15:153-63. [PMID: 27648177 PMCID: PMC5027151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND Mesial temporal lobe epilepsy (TLE) is a remediable epileptic syndrome. About 40% of patients continue to have seizures after standard temporal lobectomy. It has been suggested that some of these patients could actually suffer from a more complex epileptogenic network. Because a few papers have been dedicated to this topic, we decided to write an article updating this theme. METHODS We performed a literature search using the following terminology: "temporal plus epilepsy and networks," "temporal plus epilepsy," "orbito-temporal epilepsy," "temporo-insular epilepsy," "temporo-parieto-occipital (TPO) epilepsy," "parieto-temporal epilepsy," "intracortical evoked potential and temporal plus epilepsy," "temporal lobe connectivity and epilepsy," "intracortical evoked potential and epilepsy surgery," "role of extratemporal structures in TLE," "surgical failure after temporal lobectomy," "Diffusion tensor imaging (DTI) and temporal epilepsy," and "positron emission tomography (PET) in temporal plus lobe epilepsy" in the existing PubMed databases. We searched only English and Spanish literature. Only papers that fit with the above-mentioned descriptors were included as part of the evidence. Other articles were used to reference some aspects of the temporal plus epilepsy. RESULTS A total of 48 papers from 2334 were revised. The most frequently reported auras in these groups of patients are gustatory hallucinations, vestibular illusions, laryngeal and throat constriction, atypical distribution of somatosensory symptoms (perioral and hands, bilaterally hands paresthesias, trunk and other). The most common signs are tonic posturing, hemifacial twist, and frequent bilateral clonic movements. Interictal electroencephalographic (EEG) patterns exhibit regional and frequently bilateral spikes and/or slow waves. The first ictal electrographic change is mostly regional. It is important to note that the evidence is supported by case series or case reports. Thus, most of the data presented could represent the features on these cases and not actually the totality of the iceberg. CONCLUSION Temporal plus epilepsy is a diagnosis that can be done only after the invasive recordings have been analyzed but an adequate suspicion may arise based on clinical, EEG and imaging data.
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Affiliation(s)
- René Andrade-Machado
- Department of Epilepsy, National Institute of Neurology, CES University, Medellín, Colombia
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Bernhardt BC, Bernasconi N, Hong SJ, Dery S, Bernasconi A. Subregional Mesiotemporal Network Topology Is Altered in Temporal Lobe Epilepsy. Cereb Cortex 2016; 26:3237-48. [PMID: 26223262 PMCID: PMC4898674 DOI: 10.1093/cercor/bhv166] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is the most frequent drug-resistant epilepsy in adults and commonly associated with variable degrees of mesiotemporal atrophy on magnetic resonance imaging (MRI). Analyses of inter-regional connectivity have unveiled disruptions in large-scale cortico-cortical networks; little is known about the topological organization of the mesiotemporal lobe, the limbic subnetwork central to the disorder. We generated covariance networks based on high-resolution MRI surface-shape descriptors of the hippocampus, entorhinal cortex, and amygdala in 134 TLE patients and 45 age- and sex-matched controls. Graph-theoretical analysis revealed increased path length and clustering in patients, suggesting a shift toward a more regularized arrangement; findings were reproducible after split-half assessment and across 2 parcellation schemes. Analysis of inter-regional correlations and module participation showed increased within-structure covariance, but decreases between structures, particularly with regards to the hippocampus and amygdala. While higher clustering possibly reflects topological consequences of axonal sprouting, decreases in interstructure covariance may be a consequence of disconnection within limbic circuitry. Preoperative network parameters, specifically the segregation of the ipsilateral hippocampus, predicted long-term seizure freedom after surgery.
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Affiliation(s)
- Boris C. Bernhardt
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Deparment of Social Neuroscience, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Neda Bernasconi
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
| | - Seok-Jun Hong
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
| | - Sebastian Dery
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
| | - Andrea Bernasconi
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
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Broggini ACS, Esteves IM, Romcy-Pereira RN, Leite JP, Leão RN. Pre-ictal increase in theta synchrony between the hippocampus and prefrontal cortex in a rat model of temporal lobe epilepsy. Exp Neurol 2016; 279:232-242. [PMID: 26953232 DOI: 10.1016/j.expneurol.2016.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/03/2016] [Accepted: 03/03/2016] [Indexed: 12/15/2022]
Abstract
The pathologically synchronized neuronal activity in temporal lobe epilepsy (TLE) can be triggered by network events that were once normal. Under normal conditions, hippocampus and medial prefrontal cortex (mPFC) work in synchrony during a variety of cognitive states. Abnormal changes in this circuit may aid to seizure onset and also help to explain the high association of TLE with mood disorders. We used a TLE rat model generated by perforant path (PP) stimulation to understand whether synchrony between dorsal hippocampal and mPFC networks is altered shortly before a seizure episode. We recorded hippocampal and mPFC local field potentials (LFPs) of animals with spontaneous recurrent seizures (SRSs) to verify the connectivity between these regions. We showed that SRSs decrease hippocampal theta oscillations whereas coherence in theta increases over time prior to seizure onset. This increase in synchrony is accompanied by a stronger coupling between hippocampal theta and mPFC gamma oscillation. Finally, using Granger causality we showed that hippocampus/mPFC synchrony increases in the pre-ictal phase and this increase is likely to be caused by hippocampal networks. The dorsal hippocampus is not directly connected to the mPFC; however, the functional coupling in theta between these two structures rises pre-ictally. Our data indicates that the increase in synchrony between dorsal hippocampus and mPFC may be predictive of seizures and may help to elucidate the network mechanisms that lead to seizure generation.
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Affiliation(s)
- Ana Clara Silveira Broggini
- Department of Neurosciences and Behavior, Ribeirao Preto Medical School, University of Sao Paulo (USP), Av Bandeirantes 3900, CEP 14049-900 Ribeirao Preto, SP, Brazil.
| | - Ingrid Miranda Esteves
- Department of Neurosciences and Behavior, Ribeirao Preto Medical School, University of Sao Paulo (USP), Av Bandeirantes 3900, CEP 14049-900 Ribeirao Preto, SP, Brazil
| | - Rodrigo Neves Romcy-Pereira
- Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, 59056-450 Natal, RN, Brazil
| | - João Pereira Leite
- Department of Neurosciences and Behavior, Ribeirao Preto Medical School, University of Sao Paulo (USP), Av Bandeirantes 3900, CEP 14049-900 Ribeirao Preto, SP, Brazil
| | - Richardson Naves Leão
- Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, 59056-450 Natal, RN, Brazil; Unit of Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
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Li HJ, Nie X, Gong HH, Zhang W, Nie S, Peng DC. Abnormal resting-state functional connectivity within the default mode network subregions in male patients with obstructive sleep apnea. Neuropsychiatr Dis Treat 2016; 12:203-12. [PMID: 26855576 PMCID: PMC4725694 DOI: 10.2147/ndt.s97449] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND OBJECTIVE Abnormal resting-state functional connectivity (rs-FC) between the central executive network and the default mode network (DMN) in patients with obstructive sleep apnea (OSA) has been reported. However, the effect of OSA on rs-FC within the DMN subregions remains uncertain. This study was designed to investigate whether the rs-FC within the DMN subregions was disrupted and determine its relationship with clinical symptoms in patients with OSA. METHODS Forty male patients newly diagnosed with severe OSA and 40 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (fMRI) examinations and clinical and neuropsychologic assessments. Seed-based region of interest rs-FC method was used to analyze the connectivity between each pair of subregions within the DMN, including the medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), hippocampus formation (HF), inferior parietal cortices (IPC), and medial temporal lobe (MTL). The abnormal rs-FC strength within the DMN subregions was correlated with clinical and neuropsychologic assessments using Pearson correlation analysis in patients with OSA. RESULTS Compared with GSs, patients with OSA had significantly decreased rs-FC between the right HF and the PCC, MPFC, and left MTL. However, patients with OSA had significantly increased rs-FC between the MPFC and left and right IPC, and between the left IPC and right IPC. The rs-FC between the right HF and left MTL was positively correlated with rapid eye movement (r=0.335, P=0.035). The rs-FC between the PCC and right HF was negatively correlated with delayed memory (r=-0.338, P=0.033). CONCLUSION OSA selectively impairs the rs-FC between right HF and PCC, MPFC, and left MTL within the DMN subregions, and provides an imaging indicator for assessment of cognitive dysfunction in OSA patients.
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Affiliation(s)
- Hai-Jun Li
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Xiao Nie
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Hong-Han Gong
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Wei Zhang
- Department of Pneumology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Si Nie
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - De-Chang Peng
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
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Resting-state functional connectivity in epilepsy: growing relevance for clinical decision making. Curr Opin Neurol 2015; 28:158-65. [PMID: 25734954 DOI: 10.1097/wco.0000000000000178] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE OF REVIEW Seizures produce dysfunctional, maladaptive networks, making functional connectivity an ideal technique for identifying complex brain effects of epilepsy. We review the current status of resting-state functional connectivity (rsFC) research, highlighting its potential added value to epilepsy surgery programs. RECENT FINDINGS RsFC research has demonstrated that the brain impact of seizures goes beyond the epileptogenic zone, changing connectivity patterns in widespread cortical regions. There is evidence for abnormal connectivity, but the degree to which these represent adaptive or maladaptive plasticity responses is unclear. Empirical associations with cognitive performance and psychiatric symptoms have helped understand deleterious impacts of seizures outside the epileptogenic zone. Studies in the prediction of outcome suggest that there are identifiable presurgical patterns of functional connectivity associated with a greater likelihood of positive cognitive or seizure outcomes. SUMMARY The role of rsFC remains limited in most clinical settings, but shows great promise for identifying epileptic circuits and foci, predicting outcomes following surgery, and explaining cognitive deficits and psychiatric symptoms of epilepsy. RsFC has demonstrated that even focal epilepsies constitute a network and brain systems disorder. By providing a tool to both identify and characterize the brain network impact of epileptiform activity, rsFC can make a strong contribution to presurgical algorithms in epilepsy.
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Bernhardt BC, Bonilha L, Gross DW. Network analysis for a network disorder: The emerging role of graph theory in the study of epilepsy. Epilepsy Behav 2015; 50:162-70. [PMID: 26159729 DOI: 10.1016/j.yebeh.2015.06.005] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 01/01/2023]
Abstract
Recent years have witnessed a paradigm shift in the study and conceptualization of epilepsy, which is increasingly understood as a network-level disorder. An emblematic case is temporal lobe epilepsy (TLE), the most common drug-resistant epilepsy that is electroclinically defined as a focal epilepsy and pathologically associated with hippocampal sclerosis. In this review, we will summarize histopathological, electrophysiological, and neuroimaging evidence supporting the concept that the substrate of TLE is not limited to the hippocampus alone, but rather is broadly distributed across multiple brain regions and interconnecting white matter pathways. We will introduce basic concepts of graph theory, a formalism to quantify topological properties of complex systems that has recently been widely applied to study networks derived from brain imaging and electrophysiology. We will discuss converging graph theoretical evidence indicating that networks in TLE show marked shifts in their overall topology, providing insight into the neurobiology of TLE as a network-level disorder. Our review will conclude by discussing methodological challenges and future clinical applications of this powerful analytical approach.
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Affiliation(s)
- Boris C Bernhardt
- Neuroimaging of Epilepsy Laboratory, Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada; Department of Social Neuroscience, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Leonardo Bonilha
- Department of Neurology, Medical University of South Carolina, SC, USA
| | - Donald W Gross
- Division of Neurology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Chen J, Lin D, Zhang C, Li G, Zhang N, Ruan L, Yan Q, Li J, Yu X, Xie X, Pang C, Cao L, Pan J, Xu Y. Antidepressant-like effects of ferulic acid: involvement of serotonergic and norepinergic systems. Metab Brain Dis 2015; 30:129-36. [PMID: 25483788 DOI: 10.1007/s11011-014-9635-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022]
Abstract
Ferulic acid is a polyphenol that has antioxidant, anti-inflammatory and anticancer properties. The present study analyzed the antidepressant-like potential of ferulic acid using two well-validated mouse models of despair test, tail suspension and forced swim tests. The results suggested that ferulic acid treatment at doses of 10, 20, 40 and 80 mg/kg (p.o.) significantly reduced the immobility time in both of these two tests. These doses that affected the depressive-like behaviors did now show any effect on locomotion counts. The further neurochemical assays suggested that ferulic acid increased monoamine neurotransmitter levels in the brain regions that are relative to mood disorders: the hippocampus and frontal cortex. The increased tend to serotonin and norepinephrine was also found in the hypothalamus after higher dose of ferulic acid treatment. The subsequent study suggested that monoamine oxidase A (MAO-A) activity was inhibited in the frontal cortex and hippocampus when treatment with 40 and 80 mg/kg ferulic acid; while MAO-B activity did not change significantly. The current study provides the first lines of evidence that serotonin and norepinephrine, but not dopamine levels were elevated in mouse hippocampus and frontal cortex after ferulic acid treatment. These changes may be attributable to the inhibition of MAO-A activities in the same brain regions.
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Affiliation(s)
- Jianliang Chen
- Department of Otolaryngology, Jiangsu University Affiliated Yixing People's Hospital, Yixing, Jiangsu Province, 214200, China,
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Stretton J, Pope RA, Winston GP, Sidhu MK, Symms M, Duncan JS, Koepp M, Thompson PJ, Foong J. Temporal lobe epilepsy and affective disorders: the role of the subgenual anterior cingulate cortex. J Neurol Neurosurg Psychiatry 2015; 86:144-51. [PMID: 24876189 PMCID: PMC4316913 DOI: 10.1136/jnnp-2013-306966] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Reduced deactivation within the default mode network (DMN) is common in individuals with primary affective disorders relative to healthy volunteers (HVs). It is unknown whether similar network abnormalities are present in temporal lobe epilepsy (TLE) patients with a history of affective psychopathology. METHODS 17 TLE patients with a lifetime affective diagnosis, 31 TLE patients with no formal psychiatric history and 30 HVs were included. We used a visuo-spatial 'n-back' paradigm to compare working memory (WM) network activation between these groups. Post hoc analyses included voxel-based morphometry and diffusion tensor imaging. The Beck Depression Inventory-Fast Screen and Beck Anxiety Inventory were completed on the day of scanning. FINDINGS Each group activated the fronto-parietal WM networks and deactivated the typical DMN in response to increasing task demands. Group comparison revealed that TLE patients with lifetime affective morbidity showed significantly greater deactivation in subgenual anterior cingulate cortex (sACC) than either the TLE-only or the HVs (p<0.001). This effect persisted after covarying for current psychotropic medication and severity of current depressive/anxiety symptoms (all p<0.001). Correlational analysis revealed that this finding was not driven by differences in task performance. There were no significant differences in grey matter volume or structural connectivity between the TLE groups. CONCLUSIONS Our results provide novel evidence suggesting that affective psychopathology in TLE has a neurobiological correlate, and in this context the sACC performs differently compared with network activity in primary affective disorders.
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Affiliation(s)
- J Stretton
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK MRC Cognition and Brain Science Unit, Cambridge, UK
| | - R A Pope
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK Clinical Psychopharmacology Unit, University College London, London, UK
| | - G P Winston
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
| | - M K Sidhu
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
| | - M Symms
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
| | - J S Duncan
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
| | - M Koepp
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
| | - P J Thompson
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
| | - J Foong
- Epilepsy Society MRI Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
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Caciagli L, Bernhardt BC, Hong SJ, Bernasconi A, Bernasconi N. Functional network alterations and their structural substrate in drug-resistant epilepsy. Front Neurosci 2014; 8:411. [PMID: 25565942 PMCID: PMC4263093 DOI: 10.3389/fnins.2014.00411] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 11/24/2014] [Indexed: 12/24/2022] Open
Abstract
The advent of MRI has revolutionized the evaluation and management of drug-resistant epilepsy by allowing the detection of the lesion associated with the region that gives rise to seizures. Recent evidence indicates marked chronic alterations in the functional organization of lesional tissue and large-scale cortico-subcortical networks. In this review, we focus on recent methodological developments in functional MRI (fMRI) analysis techniques and their application to the two most common drug-resistant focal epilepsies, i.e., temporal lobe epilepsy related to mesial temporal sclerosis and extra-temporal lobe epilepsy related to focal cortical dysplasia. We put particular emphasis on methodological developments in the analysis of task-free or “resting-state” fMRI to probe the integrity of intrinsic networks on a regional, inter-regional, and connectome-wide level. In temporal lobe epilepsy, these techniques have revealed disrupted connectivity of the ipsilateral mesiotemporal lobe, together with contralateral compensatory reorganization and striking reconfigurations of large-scale networks. In cortical dysplasia, initial observations indicate functional alterations in lesional, peri-lesional, and remote neocortical regions. While future research is needed to critically evaluate the reliability, sensitivity, and specificity, fMRI mapping promises to lend distinct biomarkers for diagnosis, presurgical planning, and outcome prediction.
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Affiliation(s)
- Lorenzo Caciagli
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University Montreal, QC, Canada
| | - Boris C Bernhardt
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University Montreal, QC, Canada
| | - Seok-Jun Hong
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University Montreal, QC, Canada
| | - Andrea Bernasconi
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University Montreal, QC, Canada
| | - Neda Bernasconi
- Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University Montreal, QC, Canada
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Kemmotsu N, Kucukboyaci NE, Leyden KM, Cheng CE, Girard HM, Iragui VJ, Tecoma ES, McDonald CR. Frontolimbic brain networks predict depressive symptoms in temporal lobe epilepsy. Epilepsy Res 2014; 108:1554-63. [PMID: 25223729 PMCID: PMC4194230 DOI: 10.1016/j.eplepsyres.2014.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 07/10/2014] [Accepted: 08/21/2014] [Indexed: 01/10/2023]
Abstract
Psychiatric co-morbidities in epilepsy are of great concern. The current study investigated the relative contribution of structural and functional connectivity (FC) between medial temporal (MT) and prefrontal regions in predicting levels of depressive symptoms in patients with temporal lobe epilepsy (TLE). Twenty-one patients with TLE [11 left TLE (LTLE); 10 right TLE (RTLE)] and 20 controls participated. Diffusion tensor imaging was performed to obtain fractional anisotropy (FA) of the uncinate fasciculus (UF), and mean diffusivity (MD) of the amygdala (AM) and hippocampus (HC). Functional MRI was performed to obtain FC strengths between the AM and HC and prefrontal regions of interest including anterior prefrontal (APF), orbitofrontal, and inferior frontal regions. Participants self-reported depression symptoms on the Beck Depression Inventory-II. Greater depressive symptoms were associated with stronger FC of ipsilateral HC-APF, lower FA of the bilateral UF, and higher MD of the ipsilateral HC in LTLE, and with lower FA of the contralateral UF in RTLE. Regression analyses indicated that FC of the ipsilateral HC-APF was the strongest contributor to depression in LTLE, explaining 68.7% of the variance in depression scores. Both functional and microstructural measures of frontolimbic dysfunction were associated with depressive symptoms. These connectivity variables may be moderating which patients present with depression symptoms. In particular, FC MRI may provide a more sensitive measure of depression-related dysfunction, at least in patients with LTLE. Employing sensitive measures of frontolimbic network dysfunction in TLE may help provide new insight into mood disorders in epilepsy that could eventually guide treatment planning.
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Affiliation(s)
- Nobuko Kemmotsu
- Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
| | - N Erkut Kucukboyaci
- Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA; SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA.
| | - Kelly M Leyden
- Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA.
| | - Christopher E Cheng
- Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA.
| | - Holly M Girard
- SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA.
| | - Vicente J Iragui
- Department of Neuroscience, University of California, San Diego, La Jolla, CA, USA.
| | - Evelyn S Tecoma
- SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA; Department of Neuroscience, University of California, San Diego, La Jolla, CA, USA.
| | - Carrie R McDonald
- Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA.
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