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Song C, Xie S, Zhang X, Han S, Lian Y, Ma K, Mao X, Zhang Y, Cheng J. Similarities and differences of dynamic and static spontaneous brain activity between left and right temporal lobe epilepsy. Brain Imaging Behav 2024; 18:352-367. [PMID: 38087148 DOI: 10.1007/s11682-023-00835-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2023] [Indexed: 06/07/2024]
Abstract
To comprehensively investigate the potential temporal dynamic and static abnormalities of spontaneous brain activity (SBA) in left temporal lobe epilepsy (LTLE) and right temporal lobe epilepsy (RTLE) and to detect whether these alterations correlate with cognition. Twelve SBA metrics, including ALFF, dALFF, fALFF, dfALFF, ReHo, dReHo, DC, dDC, GSCorr, dGSCorr, VMHC, and dVMHC, in 46 LTLE patients, 43 RTLE patients, and 53 healthy volunteers were compared in the voxel-wise analysis. Correlation analyses between metrics in regions showing statistic differences and epilepsy duration, epilepsy severity, and cognition scores were also performed. Compared with the healthy volunteers, the alteration of SBA was identified both in LTLE and RTLE patients. The ALFF, fALFF, and dALFF values in LTLE, as well as the fALFF values in RTLE, increased in the bilateral thalamus, basal ganglia, mesial temporal lobe, cerebellum, and vermis. Increased dfALFF in the bilateral basal ganglia, increased ReHo and dReHo in the bilateral thalamus in the LTLE group, increased ALFF and dALFF in the pons, and increased ReHo and dReHo in the right hippocampus in the RTLE group were also detected. However, the majority of deactivation clusters were in the ipsilateral lateral temporal lobe. For LTLE, the fALFF, DC, dDC, and GSCorr values in the left lateral temporal lobe and the ReHo and VMHC values in the bilateral lateral temporal lobe all decreased. For RTLE, the ALFF, fALFF, dfALFF, ReHo, dReHo, and DC values in the right lateral temporal lobe and the VMHC values in the bilateral lateral temporal lobe all decreased. Moreover, for both the LTLE and RTLE groups, the dVMHC values decreased in the calcarine cortex. The most significant difference between LTLE and RTLE was the higher activation in the cerebellum of the LTLE group. The alterations of many SBA metrics were correlated with cognition and epilepsy duration. The patterns of change in SBA abnormalities in the LTLE and RTLE patients were generally similar. The integrated application of temporal dynamic and static SBA metrics might aid in the investigation of the propagation and suppression pathways of seizure activity as well as the cognitive impairment mechanisms in TLE.
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Affiliation(s)
- Chengru Song
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China
| | - Shanshan Xie
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China
| | - Xiaonan Zhang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China
| | - Shaoqiang Han
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China
| | - Yajun Lian
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Keran Ma
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China
| | - Xinyue Mao
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China
| | - Yong Zhang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China.
| | - Jingliang Cheng
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe Dong Road, Zhengzhou, 450052, China.
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Audrain S, Barnett A, Mouseli P, McAndrews MP. Leveraging the resting brain to predict memory decline after temporal lobectomy. Epilepsia 2023; 64:3061-3072. [PMID: 37643922 DOI: 10.1111/epi.17767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
OBJECTIVE Predicting memory morbidity after temporal lobectomy in patients with temporal lobe epilepsy (TLE) relies on indices of preoperative temporal lobe structural and functional integrity. However, epilepsy is increasingly considered a network disorder, and memory a network phenomenon. We assessed the utility of functional network measures to predict postoperative memory changes. METHODS Seventy-two adults with TLE (37 left/35 right) underwent preoperative resting-state functional magnetic resonance imaging and pre- and postoperative neuropsychological assessment. We compared functional connectivity throughout the memory network of each patient to a healthy control template (n = 19) to identify differences in global organization. A second metric indicated the degree of integration of the to-be-resected temporal lobe with the rest of the memory network. We included these measures in a linear regression model alongside standard clinical variables as predictors of memory change after surgery. RESULTS Left TLE patients with more atypical memory networks, and with greater functional integration of the to-be-resected region with the rest of the memory network preoperatively, experienced the greatest decline in verbal memory after surgery. Together, these two measures explained 44% of variance in verbal memory change, outperforming standard clinical and demographic variables. None of the variables examined was associated with visuospatial memory change in patients with right TLE. SIGNIFICANCE Resting-state connectivity provides valuable information concerning both the integrity of to-be-resected tissue and functional reserve across memory-relevant regions outside of the to-be-resected tissue. Intrinsic functional connectivity has the potential to be useful for clinical decision-making regarding memory outcomes in left TLE, and more work is needed to identify the factors responsible for differences seen in right TLE.
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Affiliation(s)
- Sam Audrain
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Alexander Barnett
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Pedram Mouseli
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Mary Pat McAndrews
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
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Karpychev V, Malyutina S, Zhuravleva A, Bronov O, Kuzin V, Marinets A, Dragoy O. Disruptions in modular structure and network integration of language-related network predict language performance in temporal lobe epilepsy: Evidence from graph-based analysis. Epilepsy Behav 2023; 147:109407. [PMID: 37688840 DOI: 10.1016/j.yebeh.2023.109407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/03/2023] [Accepted: 08/19/2023] [Indexed: 09/11/2023]
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) is a network disorder that alters the total organization of the language-related network. Task-based functional magnetic resonance imaging (fMRI) aimed at functional connectivity is a direct method to investigate how the network is reorganized. However, such studies are scarce and represented mostly by the resting-state analysis of the individual connections between regions. To fill this gap, we used a graph-based analysis, which allows us to cover the total language-related network changes, such as disruptions in an integration/segregation balance, during a language task in TLE. METHODS We collected task-based fMRI data with sentence completion from 19 healthy controls and 28 people with left TLE. Using graph-based analysis, we estimated how the language-related network segregated into modules and tested whether they differed between groups. We evaluated the total network integration and the integration within modules. To assess intermodular integration, we considered the number and location of connector hubs-regions with high connectivity. RESULTS The language-related network was differently segregated during language processing in the groups. While healthy controls showed a module consisting of left perisylvian regions, people with TLE exhibited a bilateral module formed by the anterior language-related areas and a module in the left temporal lobe, reflecting hyperconnectivity within the epileptic focus. As a consequence of this reorganization, there was a statistical tendency that the dominance of the intramodular integration over the total network integration was greater in TLE, which predicted language performance. The increase in the number of connector hubs in the right hemisphere, in turn, was compensatory in TLE. SIGNIFICANCE Our study provides insights into the reorganization of the language-related network in TLE, revealing specific network changes in segregation and integration. It confirms reduced global connectivity and compensation across the healthy hemisphere, commonly observed in epilepsy. These findings advance the understanding of the network-based reorganizational processes underlying language processing in TLE.
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Affiliation(s)
- Victor Karpychev
- Center for Language and Brain, HSE University, Moscow, Russian Federation.
| | - Svetlana Malyutina
- Center for Language and Brain, HSE University, Moscow, Russian Federation
| | - Anna Zhuravleva
- Center for Language and Brain, HSE University, Moscow, Russian Federation
| | - Oleg Bronov
- National Medical and Surgical Center named after N.I. Pirogov, Moscow, Russian Federation
| | - Vasiliy Kuzin
- National Medical and Surgical Center named after N.I. Pirogov, Moscow, Russian Federation
| | - Aleksei Marinets
- National Medical and Surgical Center named after N.I. Pirogov, Moscow, Russian Federation
| | - Olga Dragoy
- Center for Language and Brain, HSE University, Moscow, Russian Federation; Institute of Linguistics, Russian Academy of Sciences, Moscow, Russian Federation
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Gunnarsdottir KM, Li A, Smith RJ, Kang JY, Korzeniewska A, Crone NE, Rouse AG, Cheng JJ, Kinsman MJ, Landazuri P, Uysal U, Ulloa CM, Cameron N, Cajigas I, Jagid J, Kanner A, Elarjani T, Bicchi MM, Inati S, Zaghloul KA, Boerwinkle VL, Wyckoff S, Barot N, Gonzalez-Martinez J, Sarma SV. Source-sink connectivity: a novel interictal EEG marker for seizure localization. Brain 2022; 145:3901-3915. [PMID: 36412516 PMCID: PMC10200292 DOI: 10.1093/brain/awac300] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 07/05/2022] [Accepted: 08/01/2022] [Indexed: 07/26/2023] Open
Abstract
Over 15 million epilepsy patients worldwide have drug-resistant epilepsy. Successful surgery is a standard of care treatment but can only be achieved through complete resection or disconnection of the epileptogenic zone, the brain region(s) where seizures originate. Surgical success rates vary between 20% and 80%, because no clinically validated biological markers of the epileptogenic zone exist. Localizing the epileptogenic zone is a costly and time-consuming process, which often requires days to weeks of intracranial EEG (iEEG) monitoring. Clinicians visually inspect iEEG data to identify abnormal activity on individual channels occurring immediately before seizures or spikes that occur interictally (i.e. between seizures). In the end, the clinical standard mainly relies on a small proportion of the iEEG data captured to assist in epileptogenic zone localization (minutes of seizure data versus days of recordings), missing opportunities to leverage these largely ignored interictal data to better diagnose and treat patients. IEEG offers a unique opportunity to observe epileptic cortical network dynamics but waiting for seizures increases patient risks associated with invasive monitoring. In this study, we aimed to leverage interictal iEEG data by developing a new network-based interictal iEEG marker of the epileptogenic zone. We hypothesized that when a patient is not clinically seizing, it is because the epileptogenic zone is inhibited by other regions. We developed an algorithm that identifies two groups of nodes from the interictal iEEG network: those that are continuously inhibiting a set of neighbouring nodes ('sources') and the inhibited nodes themselves ('sinks'). Specifically, patient-specific dynamical network models were estimated from minutes of iEEG and their connectivity properties revealed top sources and sinks in the network, with each node being quantified by source-sink metrics. We validated the algorithm in a retrospective analysis of 65 patients. The source-sink metrics identified epileptogenic regions with 73% accuracy and clinicians agreed with the algorithm in 93% of seizure-free patients. The algorithm was further validated by using the metrics of the annotated epileptogenic zone to predict surgical outcomes. The source-sink metrics predicted outcomes with an accuracy of 79% compared to an accuracy of 43% for clinicians' predictions (surgical success rate of this dataset). In failed outcomes, we identified brain regions with high metrics that were untreated. When compared with high frequency oscillations, the most commonly proposed interictal iEEG feature for epileptogenic zone localization, source-sink metrics outperformed in predictive power (by a factor of 1.2), suggesting they may be an interictal iEEG fingerprint of the epileptogenic zone.
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Affiliation(s)
| | - Adam Li
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Rachel J Smith
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Joon-Yi Kang
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Anna Korzeniewska
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Nathan E Crone
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Adam G Rouse
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jennifer J Cheng
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Michael J Kinsman
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Patrick Landazuri
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Utku Uysal
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Carol M Ulloa
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nathaniel Cameron
- Department of Neurosurgery, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Iahn Cajigas
- Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jonathan Jagid
- Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Andres Kanner
- Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Turki Elarjani
- Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Manuel Melo Bicchi
- Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sara Inati
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Varina L Boerwinkle
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
| | - Sarah Wyckoff
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
| | - Niravkumar Barot
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | | | - Sridevi V Sarma
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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Song C, Zhang X, Han S, Ma K, Wang K, Mao X, Lian Y, Zhang X, Zhu J, Zhang Y, Cheng J. More than just statics: Static and temporal dynamic changes in intrinsic brain activity in unilateral temporal lobe epilepsy. Front Hum Neurosci 2022; 16:971062. [PMID: 36118964 PMCID: PMC9471141 DOI: 10.3389/fnhum.2022.971062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/01/2022] [Indexed: 11/17/2022] Open
Abstract
Background Temporal lobe epilepsy (TLE) is the most prevalent refractory focal epilepsy and is more likely accompanied by cognitive impairment. The fully understanding of the neuronal activity underlying TLE is of great significance. Objective This study aimed to comprehensively explore the potential brain activity abnormalities affected by TLE and detect whether the changes were associated with cognition. Methods Six static intrinsic brain activity (IBA) indicators [amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), regional homogeneity (ReHo), degree centrality (DC), global signal correlation (GSCorr), and voxel-mirrored homotopic connectivity (VMHC)] and their corresponding dynamic indicators, such as dynamic ALFF (dALFF), dynamic fALFF (dfALFF), dynamic ReHo (dReHo), dynamic DC (dDC), dynamic VMHC (dVMHC), and dynamic GSCorr (dGSCorr), in 57 patients with unilateral TLE and 42 healthy volunteers were compared. Correlation analyses were also performed between these indicators in areas displaying group differences and cognitive function, epilepsy duration, and severity. Results Marked overlap was present among the abnormal brain regions detected using various static and dynamic indicators, primarily including increased ALFF/dALFF/fALFF in the bilateral medial temporal lobe and thalamus, decreased ALFF/dALFF/fALFF in the frontal lobe contralateral to the epileptogenic side, decreased fALFF, ReHo, dReHo, DC, dDC, GSCorr, dGSCorr, and VMHC in the temporal neocortex ipsilateral to the epileptogenic foci, decreased dReHo, dDC, dGSCorr, and dVMHC in the occipital lobe, and increased ALFF, fALFF, dfALFF, ReHo, and DC in the supplementary motor area ipsilateral to the epileptogenic foci. Furthermore, most IBA indicators in the abnormal brain region significantly correlated with the duration of epilepsy and several cognitive scale scores (P < 0.05). Conclusion The combined application of static and dynamic IBA indicators could comprehensively reveal more real abnormal neuronal activity and the impairment and compensatory mechanisms of cognitive function in TLE. Moreover, it might help in the lateralization of epileptogenic foci and exploration of the transmission and inhibition pathways of epileptic activity.
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Affiliation(s)
- Chengru Song
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Xiaonan Zhang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Shaoqiang Han
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Keran Ma
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Kefan Wang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Xinyue Mao
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Yajun Lian
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | - Jinxia Zhu
- MR Collaboration, Siemens Healthcare Ltd., Beijing, China
| | - Yong Zhang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Jingliang Cheng
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China
- Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China
- Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China
- Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China
- Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
- Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
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Sala-Padro J, Gifreu-Fraixino A, Miró J, Rodriguez-Fornells A, Rico I, Plans G, Santurino M, Falip M, Càmara E. Verbal Learning and Longitudinal Hippocampal Network Connectivity in Temporal Lobe Epilepsy Surgery. Front Neurol 2022; 13:854313. [PMID: 35800085 PMCID: PMC9253296 DOI: 10.3389/fneur.2022.854313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022] Open
Abstract
Introduction Learning new verbal information can be impaired in 20–40% of patients after mesial temporal lobe resection. In recent years, understanding epilepsy as a brain network disease, and investigating the relationship between large-scale resting networks and cognition has led to several advances. Aligned studies suggest that it is the integrity of the hippocampal connectivity with these large-scale networks what is relevant for cognition, with evidence showing a functional and structural heterogeneity along the long axis hippocampus bilaterally. Objective Our aim is to examine whether pre-operative resting-state connectivity along the long hippocampal axis is associated with verbal learning decline after anterior temporal lobe resection. Methods Thirty-one patients with epilepsy who underwent an anterior temporal lobe resection were pre-surgically scanned at 3-tesla, and pre/post-surgery evaluated for learning deficits using the Rey Auditory Verbal Learning Task (RAVLT). Eighteen controls matched by age, gender and handedness were also scanned and evaluated with the RAVLT. We studied the functional connectivity along the (anterior/posterior) long axis hippocampal subregions and resting-state functionally-defined brain networks involved in learning [executive (EXE), dorsal attention (DAN) and default-mode (DMN) networks]. Functional connectivity differences between the two groups of patients (learning intact or with learning decline) and controls were investigated with MANOVA and discriminant analysis. Results There were significant differences in the pattern of hippocampal connectivity among the groups. Regarding the anterior connectivity hippocampal pattern, our data showed an increase of connectivity in the pathological side with the DAN (p = 0.011) and the EXE (p = 0.008) when comparing learning-decline vs. learning-intact patients. Moreover, the non-pathological side showed an increase in the anterior connectivity pattern with the DAN (p = 0.027) between learning-decline vs. learning-intact patients. In contrast, the posterior hippocampus showed a reduction of connectivity in the learning-decline patients with the DMN, both in the pathological (p = 0.004) and the non-pathological sides (p = 0.036). Finally, the discriminant analysis based on the pre-operative connectivity pattern significantly differentiated the learning-decline patients from the other groups (p = 0.019). Conclusion Our findings reveal bilateral connectivity disruptions along the longitudinal axis of the hippocampi with resting-state networks, which could be key to identify those patients at risk of verbal learning decline after epilepsy surgery.
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Affiliation(s)
- Jacint Sala-Padro
- Epilepsy Unit, Hospital de Bellvitge, Barcelona, Spain
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | | | - Júlia Miró
- Epilepsy Unit, Hospital de Bellvitge, Barcelona, Spain
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Antoni Rodriguez-Fornells
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
- Department of Cognition, Development and Educational Science, L'Hospitalet de Llobregat, University of Barcelona, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies, ICREA, Barcelona, Spain
| | | | - Gerard Plans
- Epilepsy Unit, Hospital de Bellvitge, Barcelona, Spain
| | | | - Mercè Falip
- Epilepsy Unit, Hospital de Bellvitge, Barcelona, Spain
| | - Estela Càmara
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
- Department of Cognition, Development and Educational Science, L'Hospitalet de Llobregat, University of Barcelona, Barcelona, Spain
- *Correspondence: Estela Càmara
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Jiang H, Kokkinos V, Ye S, Urban A, Bagić A, Richardson M, He B. Interictal SEEG Resting-State Connectivity Localizes the Seizure Onset Zone and Predicts Seizure Outcome. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200887. [PMID: 35545899 PMCID: PMC9218648 DOI: 10.1002/advs.202200887] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Indexed: 05/23/2023]
Abstract
Localization of epileptogenic zone currently requires prolonged intracranial recordings to capture seizure, which may take days to weeks. The authors developed a novel method to identify the seizure onset zone (SOZ) and predict seizure outcome using short-time resting-state stereotacticelectroencephalography (SEEG) data. In a cohort of 27 drug-resistant epilepsy patients, the authors estimated the information flow via directional connectivity and inferred the excitation-inhibition ratio from the 1/f power slope. They hypothesized that the antagonism of information flow at multiple frequencies between SOZ and non-SOZ underlying the relatively stable epilepsy resting state could be related to the disrupted excitation-inhibition balance. They found flatter 1/f power slope in non-SOZ regions compared to the SOZ, with dominant information flow from non-SOZ to SOZ regions. Greater differences in resting-state information flow between SOZ and non-SOZ regions are associated with favorable seizure outcome. By integrating a balanced random forest model with resting-state connectivity, their method localized the SOZ with an accuracy of 88% and predicted the seizure outcome with an accuracy of 92% using clinically determined SOZ. Overall, this study suggests that brief resting-state SEEG data can significantly facilitate the identification of SOZ and may eventually predict seizure outcomes without requiring long-term ictal recordings.
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Affiliation(s)
- Haiteng Jiang
- Department of Biomedical EngineeringCarnegie Mellon UniversityPittsburghPA15213USA
- Department of NeurobiologyAffiliated Mental Health Center & Hangzhou Seventh People's HospitalZhejiang University School of MedicineHangzhou310013P. R. China
- NHC and CAMS Key Laboratory of Medical NeurobiologyMOE Frontier Science Center for Brain Science and Brain‐machine IntegrationSchool of Brain Science and Brain MedicineZhejiang UniversityHangzhou310058P. R. China
| | - Vasileios Kokkinos
- University of Pittsburgh Comprehensive Epilepsy CenterDepartment of NeurologyUniversity of Pittsburgh School of MedicinePittsburghPA15232USA
- Massachusetts General HospitalBostonMA02114USA
| | - Shuai Ye
- Department of Biomedical EngineeringCarnegie Mellon UniversityPittsburghPA15213USA
| | - Alexandra Urban
- University of Pittsburgh Comprehensive Epilepsy CenterDepartment of NeurologyUniversity of Pittsburgh School of MedicinePittsburghPA15232USA
| | - Anto Bagić
- University of Pittsburgh Comprehensive Epilepsy CenterDepartment of NeurologyUniversity of Pittsburgh School of MedicinePittsburghPA15232USA
| | - Mark Richardson
- University of Pittsburgh Comprehensive Epilepsy CenterDepartment of NeurologyUniversity of Pittsburgh School of MedicinePittsburghPA15232USA
- Massachusetts General HospitalBostonMA02114USA
| | - Bin He
- Department of Biomedical EngineeringCarnegie Mellon UniversityPittsburghPA15213USA
- Neuroscience InstituteCarnegie Mellon UniversityPittsburghPA15213USA
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8
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Hao S, Yang C, Li Z, Ren J. Distinguishing patients with temporal lobe epilepsy from normal controls with the directed graph measures of resting-state fMRI. Seizure 2022; 96:25-33. [DOI: 10.1016/j.seizure.2022.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 12/30/2022] Open
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9
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Wang K, Zhang X, Song C, Ma K, Bai M, Zheng R, Wei Y, Chen J, Cheng J, Zhang Y, Han S. Decreased Intrinsic Neural Timescales in Mesial Temporal Lobe Epilepsy. Front Hum Neurosci 2021; 15:772365. [PMID: 34955790 PMCID: PMC8693765 DOI: 10.3389/fnhum.2021.772365] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/16/2021] [Indexed: 01/02/2023] Open
Abstract
It is well established that epilepsy is characterized by the destruction of the information capacity of brain network and the interference with information processing in regions outside the epileptogenic focus. However, the potential mechanism remains poorly understood. In the current study, we applied a recently proposed approach on the basis of resting-state fMRI data to measure altered local neural dynamics in mesial temporal lobe epilepsy (mTLE), which represents how long neural information is stored in a local brain area and reflect an ability of information integration. Using resting-state-fMRI data recorded from 36 subjects with mTLE and 36 healthy controls, we calculated the intrinsic neural timescales (INT) of neural signals by summing the positive magnitude of the autocorrelation of the resting-state brain activity. Compared to healthy controls, the INT values were significantly lower in patients in the right orbitofrontal cortices, right insula, and right posterior lobe of cerebellum. Whereas, we observed no statistically significant changes between patients with long- and short-term epilepsy duration or between left-mTLE and right-mTLE. Our study provides distinct insight into the brain abnormalities of mTLE from the perspective of the dynamics of the brain activity, highlighting the significant role of intrinsic timescale in understanding neurophysiological mechanisms. And we postulate that altered intrinsic timescales of neural signals in specific cortical brain areas may be the neurodynamic basis of cognitive impairment and emotional comorbidities in mTLE patients.
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Affiliation(s)
- Kefan Wang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China
| | - Xiaonan Zhang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Chengru Song
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Keran Ma
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Man Bai
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Ruiping Zheng
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Yarui Wei
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Jingli Chen
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Jingliang Cheng
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Yong Zhang
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
| | - Shaoqiang Han
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Key Laboratory for Functional Magnetic Resonance Imaging and Molecular Imaging of Henan Province, Zhengzhou, China.,Engineering Technology Research Center for Detection and Application of Brain Function of Henan Province, Zhengzhou, China.,Engineering Research Center of Medical Imaging Intelligent Diagnosis and Treatment of Henan Province, Zhengzhou, China.,Key Laboratory of Magnetic Resonance and Brain Function of Henan Province, Zhengzhou, China.,Key Laboratory of Brain Function and Cognitive Magnetic Resonance Imaging of Zhengzhou, Zhengzhou, China.,Key Laboratory of Imaging Intelligence Research Medicine of Henan Province, Zhengzhou, China
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10
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Földi T, Lőrincz ML, Berényi A. Temporally Targeted Interactions With Pathologic Oscillations as Therapeutical Targets in Epilepsy and Beyond. Front Neural Circuits 2021; 15:784085. [PMID: 34955760 PMCID: PMC8693222 DOI: 10.3389/fncir.2021.784085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022] Open
Abstract
Self-organized neuronal oscillations rely on precisely orchestrated ensemble activity in reverberating neuronal networks. Chronic, non-malignant disorders of the brain are often coupled to pathological neuronal activity patterns. In addition to the characteristic behavioral symptoms, these disturbances are giving rise to both transient and persistent changes of various brain rhythms. Increasing evidence support the causal role of these "oscillopathies" in the phenotypic emergence of the disease symptoms, identifying neuronal network oscillations as potential therapeutic targets. While the kinetics of pharmacological therapy is not suitable to compensate the disease related fine-scale disturbances of network oscillations, external biophysical modalities (e.g., electrical stimulation) can alter spike timing in a temporally precise manner. These perturbations can warp rhythmic oscillatory patterns via resonance or entrainment. Properly timed phasic stimuli can even switch between the stable states of networks acting as multistable oscillators, substantially changing the emergent oscillatory patterns. Novel transcranial electric stimulation (TES) approaches offer more reliable neuronal control by allowing higher intensities with tolerable side-effect profiles. This precise temporal steerability combined with the non- or minimally invasive nature of these novel TES interventions make them promising therapeutic candidates for functional disorders of the brain. Here we review the key experimental findings and theoretical background concerning various pathological aspects of neuronal network activity leading to the generation of epileptic seizures. The conceptual and practical state of the art of temporally targeted brain stimulation is discussed focusing on the prevention and early termination of epileptic seizures.
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Affiliation(s)
- Tamás Földi
- MTA-SZTE "Momentum" Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged, Hungary.,HCEMM-USZ Magnetotherapeutics Research Group, University of Szeged, Szeged, Hungary.,Child and Adolescent Psychiatry, Department of the Child Health Center, University of Szeged, Szeged, Hungary
| | - Magor L Lőrincz
- MTA-SZTE "Momentum" Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged, Hungary.,Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, Szeged, Hungary.,Neuroscience Division, Cardiff University, Cardiff, United Kingdom
| | - Antal Berényi
- MTA-SZTE "Momentum" Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged, Hungary.,HCEMM-USZ Magnetotherapeutics Research Group, University of Szeged, Szeged, Hungary.,Neuroscience Institute, New York University, New York, NY, United States
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11
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Oser N, Hubacher M, Nageleisen-Weiss A, van Mierlo P, Huber R, Weber P, Bölsterli BK, Datta AN. 6-year course of sleep homeostasis in a case with epilepsy-aphasia spectrum disorder. Epilepsy Behav Rep 2021; 16:100488. [PMID: 34693247 PMCID: PMC8517280 DOI: 10.1016/j.ebr.2021.100488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/27/2021] [Accepted: 09/24/2021] [Indexed: 11/11/2022] Open
Abstract
The overnight change of the slope of SSW as EEG marker for nocturnal regeneration. Reorganization of brain networks can rescue cognitive functions at least partially. Corticosteroids lead to a stabilization of the homeostasis of slope of SSW.
The epilepsy-aphasia spectrum consists of epilepsies with a strong activation of epileptic discharges during non-rapid-eye-movement (NREM) sleep, variable seizure burden and language problems. The homeostatic decrease of slow waves (SW) during NREM sleep (i.e. their amplitude/slope and power) has been related to brain recovery and cognitive function. Epileptic discharges during NREM-sleep were related to an impairment of the decrease of the slope of SW and to cognitive deficits. In this longitudinal case study, we aim to relate this electrophysiological marker, i.e. overnight change of slope of SW, to imaging and behavior. We report a young girl with a fluctuating course in the epilepsy-aphasia spectrum, ranging from the benign end with self-limited childhood epilepsy with centrotemporal spikes (SLECTS) to the severe end with epileptic encephalopathy with continuous spike waves during sleep (CSWS) with two phases of cognitive regression. She was documented over a period of six years including 12 PSGs, six language fMRIs and seven neuropsychological assessments. We longitudinally studied focal and total spike wave index (SWI), detected SW during NREM sleep, calculated their slopes (first and last hour of NREM sleep and overnight change). Deterioration of overnight decrease of the slope of SW was paralleled by the occurrence of the EEG picture of bilateral synchronous electrical status epilepticus during sleep (ESES) and neuropsychological deficits, and this impairment was reversible with resolution of ESES and was accompanied by cognitive improvement. A laterality switch from left to right sided language dominance occurred during recovery from the second regression phase. This might reflect a compensating process. Later, the laterality switched back to the left, possibly facilitated by a low SWI on the left hemisphere. The qualitative analysis of this case supports the view that the longitudinal course of the overnight change of the slope of SW, as an objective, quantitative EEG measure, is related to the course of cognitive function and functional language MR analysis.
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Affiliation(s)
- Nadine Oser
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, Basel, Switzerland
| | - Martina Hubacher
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, Basel, Switzerland
| | - Annette Nageleisen-Weiss
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, Basel, Switzerland
| | - Pieter van Mierlo
- Epilog NV, Ghent, Belgium.,Medical Image and Signal Processing Group, Ghent University, Belgium
| | - Reto Huber
- Department of Pediatric Neurology and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Switzerland.,Child Development Center and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Switzerland.,Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital, University of Zürich, Switzerland
| | - Peter Weber
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, Basel, Switzerland
| | - Bigna K Bölsterli
- Department of Pediatric Neurology and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Switzerland
| | - Alexandre N Datta
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, Basel, Switzerland
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12
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Highly consistent temporal lobe interictal spike networks revealed from foramen ovale electrodes. Clin Neurophysiol 2021; 132:2065-2074. [PMID: 34284241 DOI: 10.1016/j.clinph.2021.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVE A major challenge that limits understanding and treatment of epileptic events from mesial temporal structures comes from our inability to detect and map interictal networks reproducibly using scalp electrodes. Here, we developed a novel approach to map interictal spike networks and demonstrate their relationships to seizure onset and lesions in patients with foramen ovale electrode implantations. METHODS We applied the direct Directed Transfer Function to reveal interictal spike propagation from bilateral foramen ovale electrodes on 10 consecutive patients and co-registered spatially with both seizure onset zones and temporal lobe lesions. RESULTS Highly reproducible, yet unique interictal spike networks were seen for each patient (correlation: 0.93 ± 0.13). Interictal spikes spread in both anterior and posterior directions within each temporal lobe, often reverberating between sites. Spikes propagated to the opposite temporal lobe predominantly through posterior pathways. Patients with structural lesions (N = 4), including tumors and sclerosis, developed reproducible spike networks adjacent to their lesions that were highly lateralized compared to patients without lesions. Only 5% of mesial temporal lobe spikes were time-locked with scalp electrode spikes. Our preliminary observation on two lesional patients suggested that along with lesion location, Interictal spike networks also partially co-registered with seizure onset zones suggesting interrelationship between seizure onset and a subset of spike networks. CONCLUSIONS This is the first demonstration of patient-specific, reproducible interictal spike networks in mesial temporal structures that are closely linked to both temporal lobe lesions and seizure onset zones. SIGNIFICANCE Interictal spike connectivity is a novel approach to map epileptic networks that could help advance invasive and non-invasive epilepsy treatments.
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Changes in the Functional Brain Network of Children Undergoing Repeated Epilepsy Surgery: An EEG Source Connectivity Study. Diagnostics (Basel) 2021; 11:diagnostics11071234. [PMID: 34359317 PMCID: PMC8306224 DOI: 10.3390/diagnostics11071234] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/29/2021] [Accepted: 07/05/2021] [Indexed: 11/19/2022] Open
Abstract
About 30% of children with drug-resistant epilepsy (DRE) continue to have seizures after epilepsy surgery. Since epilepsy is increasingly conceptualized as a network disorder, understanding how brain regions interact may be critical for planning re-operation in these patients. We aimed to estimate functional brain connectivity using scalp EEG and its evolution over time in patients who had repeated surgery (RS-group, n = 9) and patients who had one successful surgery (seizure-free, SF-group, n = 12). We analyzed EEGs without epileptiform activity at varying time points (before and after each surgery). We estimated functional connectivity between cortical regions and their relative centrality within the network. We compared the pre- and post-surgical centrality of all the non-resected (untouched) regions (far or adjacent to resection) for each group (using the Wilcoxon signed rank test). In alpha, theta, and beta frequency bands, the post-surgical centrality of the untouched cortical regions increased in the SF group (p < 0.001) whereas they decreased (p < 0.05) or did not change (p > 0.05) in the RS group after failed surgeries; when re-operation was successful, the post-surgical centrality of far regions increased (p < 0.05). Our data suggest that removal of the epileptogenic focus in children with DRE leads to a gain in the network centrality of the untouched areas. In contrast, unaltered or decreased connectivity is seen when seizures persist after surgery.
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Yang C, Ren J, Li W, Lu M, Wu S, Chu T. Individual-level morphological hippocampal networks in patients with Alzheimer's disease. Brain Cogn 2021; 151:105748. [PMID: 33971496 DOI: 10.1016/j.bandc.2021.105748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 11/15/2022]
Abstract
In patients with Alzheimer's Disease (AD), the hippocampal network has been extensively investigated in previous studies; however, little is known about the morphological network associated with the hippocampus in the AD patients. A total of 68 patients with AD and another 68 gender and age matched healthy subjects were studied. Individual-level morphological hippocampal networks were constructed based on volume and texture features extracted from MRI to study the connections between bilateral hippocampus and 11 other subcortical gray matter structures. The relationship between morphological connections and Mini-Mental State Examination (MMSE) scores was also studied. Connections between bilateral hippocampus and bilateral thalamus, bilateral putamen were significant differences between the AD patients and controls (p < 0.05). There were significantly different in bilateral hippocampal connectivity, and for the left hippocampus, the connection to the right caudate were found to be statistically significant. The morphological connections between left hippocampus and bilateral thalamus (left: R = 0.371, p < 0.001; right: R = 0.411, p < 0.001), bilateral putamen (left: R = 0.383, p < 0.001; right: R = 0.348, p < 0.001), right hippocampus and bilateral thalamus (left: R = 0.370, p < 0.001; right: R = 0.387, p < 0.001), left putamen (R = 0.377, p < 0.001) were significantly positively correlated with the MMSE scores. Similar patterns were observed for left and right hippocampal connectivity and the connections highly associated with MMSE scores were also within the abnormal connections in AD patients.
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Affiliation(s)
- Chunlan Yang
- Department of Environment and Life, Beijing University of Technology, Beijing 100020, China
| | - Jiechuan Ren
- Department of Epilepsy, Neurology Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
| | - Wan Li
- Department of Environment and Life, Beijing University of Technology, Beijing 100020, China
| | - Min Lu
- Department of Environment and Life, Beijing University of Technology, Beijing 100020, China
| | - Shuicai Wu
- Department of Environment and Life, Beijing University of Technology, Beijing 100020, China
| | - Tongpeng Chu
- Department of Radiology, Yantai Yuhuangding Hospital, Affiliated Hospital of Qingdao University, Yantai, Shandong 264000, China.
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Ives-Deliperi V, Butler JT. Mechanisms of cognitive impairment in temporal lobe epilepsy: A systematic review of resting-state functional connectivity studies. Epilepsy Behav 2021; 115:107686. [PMID: 33360743 DOI: 10.1016/j.yebeh.2020.107686] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/16/2020] [Accepted: 11/30/2020] [Indexed: 12/22/2022]
Abstract
Temporal lobe epilepsy is the most common form of focal epilepsy and related cognitive dysfunction impacts significantly on quality of life in patients. Identifying the mechanisms of such impairment would assist in the management and treatment of patients. The study of perturbations in resting-state networks could shed light on this subject. The aim of this systematic review was to synthesize findings on the relationship between aberrant resting-state functional connectivity and cognitive performance in patients with TLE. Literature searches were conducted on Scopus and PubMed electronic databases and 17 relevant articles were extracted, all of which studied the association between resting-state functional connectivity (RSFC) and cognition in adults with TLE. Study findings were synthesized according to methods used to analyze resting-state data, cognitive domains tested, and neuropsychology tasks administered. Results show that increased RSFC in the primary epileptogenic hippocampus, and reduced intra-hemispheric RSFC, are associated with weaker memory performance. In left TLE, memory impairment may be compensated for by bilateral hippocampal connectivity, which is also predictive of better postoperative memory outcomes. In right TLE, memory loss may be compensated for by increased connectivity between the contralateral hippocampus and inferior frontal gyrus. There is also tentative evidence that working memory dysfunction is related to reduced RSFC between the medial frontal-insular parietal network and the medial temporal network, executive dysfunction is related to reduced RSFC between frontal and parietal lobes, and between the frontal lobe and subcortical regions and that language dysfunction is related to reduced RSFC within the left fronto-temporal language network. Multicenter studies could refute or support these findings by enrolling large samples of patients and employing multivariate regression analysis to control for the effects of anatomical disruption, interictal discharges, seizure frequency, medication, and mood. Systematic review registration: PROSPERO: 191323.
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Affiliation(s)
- Victoria Ives-Deliperi
- Neuroscience Institute, Division of Neurosurgery, University of Cape Town, South Africa.
| | - James T Butler
- Division of Neurology, Department of Medicine, University of Cape Town, South Africa
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He C, Liu P, Wu Y, Chen H, Song Y, Yin J. Gamma-aminobutyric acid (GABA) changes in the hippocampus and anterior cingulate cortex in patients with temporal lobe epilepsy. Epilepsy Behav 2021; 115:107683. [PMID: 33360398 DOI: 10.1016/j.yebeh.2020.107683] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/29/2020] [Accepted: 11/29/2020] [Indexed: 01/25/2023]
Abstract
PURPOSE To explore the changes of gamma-aminobutyric acid (GABA) levels in the bilateral hippocampus and anterior cingulate cortex (ACC) of healthy control subjects and patients with temporal lobe epilepsy (TLE) and the correlation of GABA levels with the clinical symptoms by quantitative magnetic resonance spectroscopy (MRS). METHODS N-acetylaspartate (NAA), creatine (Cr) as well as choline (Cho) and GABA levels in the bilateral hippocampus and ACC were measured in 40 patients with TLE and 26 healthy control (NC) subjects with quantitative Meshcher-Garwood point resolved spectroscopy (MEGA-PRESS). The NAA/(Cho + Cr) and GABA/Cr ratios were compared between the NC and TLE groups. Comparisons were also made between the subgroups with lateralization (left TLE, right TLE and uncertain), short (<10 years) and longer (≥10 years) clinical seizure history (CSH), low (<1/month) and higher (≥1/month) seizure frequency (SF), with and without cognitive impairment (CI) in the patients with TLE, and by antiepileptic medications. Further analyses of the clinical information and metabolite ratios between the patients with TLE with and without CI were preformed. RESULTS The GABA/Cr ratio was significantly decreased in the bilateral hippocampus (left: P = 0.028, right: P = 0.035), while the NAA/(Cho + Cr) ratio was decreased only in the right hippocampus (RH) (P = 0.004) in patients with TLE compared with that of the NCs. Whereas the NAA/(Cho + Cr) ratio showed a consistent decreasing trend in bilateral hippocampus during the CSH, it only showed a significant difference in the RH. The GABA changes in the hippocampal and ACC regions were not consistent during different stages of the disease. In the bilateral hippocampus, the GABA/Cr ratio was decreased in the short seizure history (<10 years) patients with TLE compared with NCs (left: P = 0.018, right: P = 0.012), whereas the long seizure history (≥10 years) patients with TLE showed no difference with the NCs. However, in the ACC, the GABA/Cr ratio of the CI group was significantly decreased compared with that of NCs (P = 0.015). Further analysis showed that the patients with TLE with CI had obvious atrophy of the gray matter volume (GMV) and total parenchymal brain volume (PBV); GABA/Cr ratio was decreased in ACC, but increased in bilateral hippocampus compared with that of the no cognitive impairment (NOCI) group. CONCLUSION The GABA/Cr ratio was more valuable than the NAA/(Cho + Cr) ratio in evaluating the dynamic metabolite changes in patients with TLE. Importantly, the GABA changes in the hippocampal and ACC regions were not consistent during different stages of the disease. In the bilateral hippocampus, the GABA/Cr ratio was decreased at the early stage, but recovered to normal levels later. The decreased GABA/Cr ratio in the ACC might indicate more cerebral cortex was involved, resulting in more CI in patients with TLE.
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Affiliation(s)
- Che He
- Tianjin Medical University, Tianjin, China
| | - Pei Liu
- Tianjin Medical University, Tianjin, China
| | - Yalin Wu
- Tianjin Medical University, Tianjin, China
| | - Hong Chen
- Tianjin Medical University, Tianjin, China
| | - Yijun Song
- Department of Neurology, Tianjin Medical University General Hospital, 154 Anshan Street, Tianjin 300052, China.
| | - Jianzhong Yin
- Department of Radiology, Tianjin First Central Hospital, 24 Fukang Road, Tianjin 300192, China.
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González HFJ, Narasimhan S, Johnson GW, Wills KE, Haas KF, Konrad PE, Chang C, Morgan VL, Rubinov M, Englot DJ. Role of the Nucleus Basalis as a Key Network Node in Temporal Lobe Epilepsy. Neurology 2021; 96:e1334-e1346. [PMID: 33441453 DOI: 10.1212/wnl.0000000000011523] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To determine whether the nucleus basalis of Meynert (NBM) may be a key network structure of altered functional connectivity in temporal lobe epilepsy (TLE), we examined fMRI with network-based analyses. METHODS We acquired resting-state fMRI in 40 adults with TLE and 40 matched healthy control participants. We calculated functional connectivity of NBM and used multiple complementary network-based analyses to explore the importance of NBM in TLE networks without biasing our results by our approach. We compared patients to controls and examined associations of network properties with disease metrics and neurocognitive testing. RESULTS We observed marked decreases in connectivity between NBM and the rest of the brain in patients with TLE (0.91 ± 0.88, mean ± SD) vs controls (1.96 ± 1.13, p < 0.001, t test). Larger decreases in connectivity between NBM and fronto-parietal-insular regions were associated with higher frequency of consciousness-impairing seizures (r = -0.41, p = 0.008, Pearson). A core network of altered nodes in TLE included NBM ipsilateral to the epileptogenic side and bilateral limbic structures. Furthermore, normal community affiliation of ipsilateral NBM was lost in patients, and this structure displayed the most altered clustering coefficient of any node examined (3.46 ± 1.17 in controls vs 2.23 ± 0.93 in patients). Abnormal connectivity between NBM and subcortical arousal community was associated with modest neurocognitive deficits. Finally, a logistic regression model incorporating connectivity properties of ipsilateral NBM successfully distinguished patients from control datasets with moderately high accuracy (78%). CONCLUSIONS These results suggest that while NBM is rarely studied in epilepsy, it may be one of the most perturbed network nodes in TLE, contributing to widespread neural effects in this disabling disorder.
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Affiliation(s)
- Hernán F J González
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA.
| | - Saramati Narasimhan
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Graham W Johnson
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Kristin E Wills
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Kevin F Haas
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Peter E Konrad
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Catie Chang
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Victoria L Morgan
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Mikail Rubinov
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Dario J Englot
- From the Departments of Biomedical Engineering (H.F.J.G., G.W.J., P.E.K., C.C., V.L.M., M.R., D.J.E.) and Electrical Engineering and Computer Science (C.C., V.L.M., M.R., D.J.E.), Vanderbilt University; Departments of Neurological Surgery (S.N., K.E.W., P.E.K., D.J.E.), Radiology and Radiological Sciences (V.L.M., D.J.E.), and Neurology (K.F.H.) and Vanderbilt University Institute of Imaging Science (H.F.J.G., S.N., G.W.J., K.E.W., C.C., V.L.M., D.J.E.), Vanderbilt University Medical Center, Nashville, TN; and Department of Psychology (M.R.), Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
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18
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A Review of Accelerated Long-Term Forgetting in Epilepsy. Brain Sci 2020; 10:brainsci10120945. [PMID: 33297371 PMCID: PMC7762289 DOI: 10.3390/brainsci10120945] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022] Open
Abstract
Accelerated long-term forgetting (ALF) is a memory disorder that manifests by a distinct pattern of normal memory for up to an hour after learning, but an increased rate of forgetting during the subsequent hours and days. The topic of ALF has gained much attention in group studies with epilepsy patients and the phenomenon has been shown to have contradictory associations with seizures, epileptiform activity, imaging data, sleep, and antiepileptic medication. The aim of this review was to explore how clinical and imaging data could help determine the topographic and physiological substrate of ALF, and what is the possible use of this information in the clinical setting. We have reviewed 51 group studies in English to provide a synthesis of the existing findings concerning ALF in epilepsy. Analysis of recently reported data among patients with temporal lobe epilepsy, transient epileptic amnesia, and generalized and extratemporal epilepsies provided further indication that ALF is likely a disorder of late memory consolidation. The spatial substrate of ALF might be located along the parts of the hippocampal-neocortical network and novel studies reveal the increasingly possible importance of damage in extrahippocampal sites. Further research is needed to explore the mechanisms of cellular impairment in ALF and to develop effective methods of care for patients with the disorder.
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Iannotti GR, Preti MG, Grouiller F, Carboni M, De Stefano P, Pittau F, Momjian S, Carmichael D, Centeno M, Seeck M, Korff CM, Schaller K, De Ville DV, Vulliemoz S. Modulation of epileptic networks by transient interictal epileptic activity: A dynamic approach to simultaneous EEG-fMRI. NEUROIMAGE-CLINICAL 2020; 28:102467. [PMID: 33395963 PMCID: PMC7645285 DOI: 10.1016/j.nicl.2020.102467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 09/15/2020] [Accepted: 10/09/2020] [Indexed: 12/27/2022]
Abstract
EEG-fMRI has been instrumental in characterizing brain networks in epilepsy. Its value is documented in the pre-surgical assessment of drug-resistant epilepsy. The delineation of brain areas to resect is fundamental for the post-surgical outcome. Standard EEG-fMRI in epilepsy assesses static functional connectivity of the network. EEG-fMRI dynamic connectivity identifies transitory features of specific connections. We integrate dynamic fMRI connectivity and dynamic patterns of simultaneous scalp EEG. This allows to better characterize the spatiotemporal aspects of epileptic networks. This may help in more efficiently target the surgical intervention.
Epileptic networks, defined as brain regions involved in epileptic brain activity, have been mapped by functional connectivity in simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) recordings. This technique allows to define brain hemodynamic changes, measured by the Blood Oxygen Level Dependent (BOLD) signal, associated to the interictal epileptic discharges (IED), which together with ictal events constitute a signature of epileptic disease. Given the highly time-varying nature of epileptic activity, a dynamic functional connectivity (dFC) analysis of EEG-fMRI data appears particularly suitable, having the potential to identify transitory features of specific connections in epileptic networks. In the present study, we propose a novel method, defined dFC-EEG, that integrates dFC assessed by fMRI with the information recorded by simultaneous scalp EEG, in order to identify the connections characterised by a dynamic profile correlated with the occurrence of IED, forming the dynamic epileptic subnetwork. Ten patients with drug-resistant focal epilepsy were included, with different aetiology and showing a widespread (or multilobar) BOLD activation, defined as involving at least two distinct clusters, located in two different lobes and/or extended to the hemisphere contralateral to the epileptic focus. The epileptic focus was defined from the IED-related BOLD map. Regions involved in the occurrence of interictal epileptic activity; i.e., forming the epileptic network, were identified by a general linear model considering the timecourse of the fMRI-defined focus as main regressor. dFC between these regions was assessed with a sliding-window approach. dFC timecourses were then correlated with the sliding-window variance of the IED signal (VarIED), to identify connections whose dynamics related to the epileptic activity; i.e., the dynamic epileptic subnetwork. As expected, given the very different clinical picture of each individual, the extent of this subnetwork was highly variable across patients, but was but was reduced of at least 30% with respect to the initially identified epileptic network in 9/10 patients. The connections of the dynamic subnetwork were most commonly close to the epileptic focus, as reflected by the laterality index of the subnetwork connections, reported higher than the one within the original epileptic network. Moreover, the correlation between dFC timecourses and VarIED was predominantly positive, suggesting a strengthening of the dynamic subnetwork associated to the occurrence of IED. The integration of dFC and scalp IED offers a more specific description of the epileptic network, identifying connections strongly influenced by IED. These findings could be relevant in the pre-surgical evaluation for the resection or disconnection of the epileptogenic zone and help in reaching a better post-surgical outcome. This would be particularly important for patients characterised by a widespread pathological brain activity which challenges the surgical intervention.
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Affiliation(s)
- G R Iannotti
- EEG and Epilepsy, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland; Functional Brain Mapping Lab, Department of Fundamental Neurosciences, University of Geneva, Switzerland; Neurosurgery, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland.
| | - M G Preti
- Institute of Bioengineering, Center for Neuroprosthetics, Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland; Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland
| | - F Grouiller
- Swiss Center for Affective Sciences, University of Geneva, Switzerland; Laboratory of Behavioral Neurology and Imaging of Cognition, Department of Fundamental Neurosciences, University of Geneva, Switzerland
| | - M Carboni
- EEG and Epilepsy, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland; Functional Brain Mapping Lab, Department of Fundamental Neurosciences, University of Geneva, Switzerland
| | - P De Stefano
- EEG and Epilepsy, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland
| | - F Pittau
- EEG and Epilepsy, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland; Epilepsy Unit, Institution de Lavigny, Switzerland
| | - S Momjian
- Neurosurgery, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland
| | - D Carmichael
- Biomedical Engineering Department, Kings College London, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - M Centeno
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, United Kingdom; Epilepsy Unit, Neurology Department, Clinica Universidad de Pamplona, Navarra, Spain
| | - M Seeck
- EEG and Epilepsy, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland
| | - C M Korff
- Pediatric Neurology Unit, University Hospitals of Geneva, Geneva, Switzerland
| | - K Schaller
- Neurosurgery, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland
| | - D Van De Ville
- Institute of Bioengineering, Center for Neuroprosthetics, Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland; Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland
| | - S Vulliemoz
- EEG and Epilepsy, Clinical Neuroscience Department, University Hospital and Faculty of Medicine of Geneva, Switzerland
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20
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Laurent A, Artiges E, Mellerio C, Boutin-Watine M, Landré E, Semah F, Chassoux F. Metabolic correlates of cognitive impairment in mesial temporal lobe epilepsy. Epilepsy Behav 2020; 105:106948. [PMID: 32062107 DOI: 10.1016/j.yebeh.2020.106948] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/07/2020] [Accepted: 01/24/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE The purpose of the study was to determine the correlations between brain metabolism and cognitive impairment in patients with drug-resistant mesial temporal lobe epilepsy (MTLE). METHODS [18F]-FluoroDeoxyGlucose positron emission tomography ([18F]-FDG-PET) and neuropsychological assessment were performed in 97 patients with MTLE (53 females, 15-56 years old, mean: 31.6 years, standard deviation (SD) = 10.4) with unilateral hippocampal sclerosis (HS, 49 left). We compared brain metabolism and gray matter volume (GMV) between patients with cognitive impairment (intelligence quotient (IQ) and memory index <80) and patients with normal cognition, using statistical parametric mapping (SPM), in the whole population then in right and left HS (RHS, LHS) separately. RESULTS Intelligence quotient (40-121, mean: 83.7 ± 16.9) and memory index (45-133, mean: 80.7 ± 19.3) were impaired in 43% and 51% of the patients, respectively, similarly in RHS and LHS. We did not find any correlations between IQ and clinical factors related to epilepsy; however, there was a significant correlation between low memory index and early age of onset in LHS (p = 0.021), and widespread epileptogenic zone in the whole population (p = 0.033). Impaired IQ correlated with extratemporal hypometabolism, involving frontoparietal networks implicated in the default mode network (DMN), predominantly in the midline cortices. Metabolic asymmetry regarding HS lateralization included the precuneus (pC) in LHS and the anterior cingulate cortex (ACC) in RHS, both areas corresponding to key nodes of the DMN. Memory index correlated with the same frontoparietal networks as for IQ, with an additional involvement of the temporal lobes, which was ipsilateral in RHS and contralateral in LHS. A diffuse decrease of GMV including the ipsilateral hippocampus correlated with cognitive impairment; however, the structural alterations did not match with the hypometabolic areas. CONCLUSIONS Cognitive impairment in MTLE correlates with extratemporal hypometabolism, involving the mesial frontoparietal networks implicated in the DMN and suggesting a disconnection with the affected hippocampus. Asymmetric alterations of connectivity may sustain the predominant ACC and pC metabolic decrease in patients with cognitive impairment.
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Affiliation(s)
- Agathe Laurent
- Epilepsy Unit, Department of Neurosurgery, GHU Paris Sainte-Anne, 75014 Paris, France
| | - Eric Artiges
- INSERM U1000 "Neuroimaging and Psychiatry,", Paris Sud University-Paris Saclay University, Psychiatry Department, 91G16 Orsay, France
| | - Charles Mellerio
- Department of Neuroradiology, GHU Paris Sainte-Anne, 75014 Paris, France
| | - Magali Boutin-Watine
- Epilepsy Unit, Department of Neurosurgery, GHU Paris Sainte-Anne, 75014 Paris, France
| | - Elisabeth Landré
- Epilepsy Unit, Department of Neurosurgery, GHU Paris Sainte-Anne, 75014 Paris, France
| | - Franck Semah
- Department of Nuclear Medicine and INSERM U1171, CHU Lille, F-59000 Lille, France
| | - Francine Chassoux
- Epilepsy Unit, Department of Neurosurgery, GHU Paris Sainte-Anne, 75014 Paris, France; Nuclear Medicine Department, SHFJ, Orsay, France; University Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, 91401, France.
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21
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Morgan VL, Chang C, Englot DJ, Rogers BP. Temporal lobe epilepsy alters spatio-temporal dynamics of the hippocampal functional network. NEUROIMAGE-CLINICAL 2020; 26:102254. [PMID: 32251905 PMCID: PMC7132094 DOI: 10.1016/j.nicl.2020.102254] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022]
Abstract
Mesial temporal lobe epilepsy (TLE) is characterized by transient abnormal electrical activity originating in the hippocampus. The objective of this study was to characterize dynamic spatio-temporal fluctuations in hippocampal network connectivity in mTLE using functional connectivity (FC) mapping in 41 unilateral mTLE patients (28 right, 13 left) and 56 healthy control participants using 3T MRI. Dynamic FC was computed across the scan using sliding 60-s windows. This was compared to static FC computed using the whole 10-min functional MRI scan, and to the variance in the hippocampal functional MRI signal. Four states of healthy hippocampal dynamic FC were identified and compared to TLE patients. TLE patients fluctuated between these four states, but the hippocampus ipsilateral to the seizure focus spent more time in a state distinguished by lower prefrontal and parietal FC than the dominant healthy state. Increased time spent in this state was associated with increased impairment in static FC and increased variance in the hippocampal functional MRI signal. Overall, this work provides evidence that increases in variance in signal fluctuations occurring at the seizure focus in the hippocampus in patients with mTLE may contribute to disruptions in healthy FC network dynamics within an fMRI scan that contribute to decreases in static hippocampal FC. These alterations result in decreased hippocampal connectivity to bilateral prefrontal and parietal regions in TLE which may be related to behavior and cognitive impairments in these patients. Therefore, characterization of an individual patient's hippocampal dynamics at different time scales may provide more specific spatio-temporal profiles of network impairment that may be related to hippocampal dysfunction in TLE.
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Affiliation(s)
- Victoria L Morgan
- Institute of Imaging Science, Vanderbilt University Medical Center, USA.
| | - Catie Chang
- Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Electrical Engineering and Computer Science, Vanderbilt University, USA
| | - Dario J Englot
- Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Neurological Surgery, Vanderbilt University Medical Center, USA
| | - Baxter P Rogers
- Institute of Imaging Science, Vanderbilt University Medical Center, USA
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22
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Lee HJ, Park KM. Intrinsic hippocampal and thalamic networks in temporal lobe epilepsy with hippocampal sclerosis according to drug response. Seizure 2020; 76:32-38. [PMID: 31986443 DOI: 10.1016/j.seizure.2020.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/31/2019] [Accepted: 01/15/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE The aim of this study was to investigate whether intrinsic hippocampal or thalamic networks in patients with temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS) were different according to antiepileptic drug (AED) response. METHODS We enrolled 80 patients with TLE with HS and 40 healthy controls. Of the patients with TLE with HS, 43 were classified as a drug-resistant epilepsy (DRE) group, whereas 37 patients were enrolled as a drug-controlled epilepsy (DCE) group. We investigated the structural connectivity of the global brain, intrinsic hippocampal, and intrinsic thalamic networks based on structural volumes in the patients with DRE and DCE, and analyzed the differences between them. RESULTS There were significant alterations of the intrinsic hippocampal network compared with healthy controls. The average degree and the global efficiency were decreased, whereas the characteristic path length was increased in the patients with DRE compared with those in healthy controls. In the patients with DCE, only the small-worldness index was decreased compared with healthy controls. Compared to the patients with DCE, the mean clustering coefficient was increased in the patients with DRE. CONCLUSION We found that the intrinsic hippocampal network in patients with TLE with HS was different according to AED response. The patients with DRE had more severe disruptions of the intrinsic hippocampal network than those with DCE compared with healthy controls. These findings suggested that the hippocampal network might be related to AED response and could be a new biomarker of medical outcome in patients with TLE with HS.
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Affiliation(s)
- Ho-Joon Lee
- Department of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea.
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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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Zhou X, Zhang Z, Liu J, Qin L, Pang X, Zheng J. Disruption and lateralization of cerebellar-cerebral functional networks in right temporal lobe epilepsy: A resting-state fMRI study. Epilepsy Behav 2019; 96:80-86. [PMID: 31103016 DOI: 10.1016/j.yebeh.2019.03.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/13/2019] [Accepted: 03/13/2019] [Indexed: 01/05/2023]
Abstract
Numerous studies have highlighted important roles for the cerebellum in cognition and movement, based on numerous fiber connections between the cerebrum and cerebellum. Abnormal cerebellar activity caused by epileptic discharges has been reported in previous studies, but researchers have not clearly determined whether aberrant cerebellar activity contributes to the disruption of the cerebellar-cerebral networks in right temporal lobe epilepsy (rTLE). Here, thirty patients with rTLE and 30 age- and sex-matched healthy controls (HCs) were recruited. All participants underwent the Attention Network Test (ANT) and resting-state functional magnetic resonance imaging (rs-fMRI) scanning. Cerebellar functional networks were extracted and analyzed by defining seeds in the cerebellum. A correlation analysis was performed between attentional performance and voxels that showed differences in functional connectivity (FC) in patients compared with HCs. Relative to HCs, patients exhibited significantly decreased FC in the dentate nucleus (DN) network (right DN with the left postcentral gyrus, left precentral gyrus, left cuneus, and left calcarine gyrus) and motor network (right cerebellar lobule V with the right putamen) and increased FC in the executive control network (right cerebellar crus I with the right inferior parietal lobule). Alerting, orienting, and executive control performances were impaired in patients with rTLE. Furthermore, the executive control effect was significantly correlated with aberrant FC strength between the right DN and the left precentral/postcentral gyrus. Our findings highlight that the disrupted cerebellar-cerebral functional network ipsilateral to the epileptogenic focus causes both impairments in and compensatory effects on attentional deficits in patients with rTLE. These findings contribute to our understanding of the cerebellar damage caused by epileptic discharges and the corresponding effect on attentional performance.
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Affiliation(s)
- Xia Zhou
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zhao Zhang
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jinping Liu
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Lu Qin
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xiaomin Pang
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jinou Zheng
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.
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Comparing the Wada Test and Functional MRI for the Presurgical Evaluation of Memory in Temporal Lobe Epilepsy. Curr Neurol Neurosci Rep 2019; 19:31. [PMID: 31044310 DOI: 10.1007/s11910-019-0945-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW The usefulness of the Wada test (WT) predicting memory impairment from temporal lobe epilepsy (TLE) surgery has been debated, and it has progressively been replaced by functional MRI (fMRI). We review the current role of WT and fMRI in the presurgical assessment of TLE, and how novel surgical techniques might improve cognitive outcomes. RECENT FINDINGS fMRI's ability to predict global amnesia has not been assessed. Although WT can produce false-positive results, it is still indicated in patients at risk for developing global amnesia: those with significant bilateral or contralateral memory deficits. In the current review, WT exhibited no added value, beyond preclinical data, for predicting material-specific memory impairment, whereas fMRI was reliable for either verbal or non-verbal memory decline. Abnormal functional connectivity on resting state fMRI (rs-fMRI) between the posterior cingulate and the hippocampus may be a predictor of postsurgical memory outcomes. Restricted resections to the pathogenic tissue, stereotactic laser, radiosurgery, and SEEG-guided thermos-coagulation were associated with better cognitive outcome. fMRI should be used routinely in the presurgical workup of TLE to predict verbal and/or non-verbal memory decline, whereas WT may be indicated when there is a high risk of postsurgical global amnesia. Rs-fMRI is a promising tool for the presurgical workup of TLE, and more restricted resections are recommended to enhance cognitive outcomes.
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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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Zhang C, Yang H, Liu C, Zhang G, Chen N, Li K. Brain network alterations of mesial temporal lobe epilepsy with cognitive dysfunction following anterior temporal lobectomy. Epilepsy Behav 2018; 87:123-130. [PMID: 30115603 DOI: 10.1016/j.yebeh.2018.07.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/01/2018] [Accepted: 07/21/2018] [Indexed: 11/17/2022]
Abstract
The aims of this study were to investigate the brain network connectivity alterations of intractable unilateral mesial temporal lobe epilepsy (MTLE) with cognitive dysfunction before and after anterior temporal lobectomy (ATL) using resting-state functional magnetic resonance imaging (rs-fMRI) study and to further observe the correlation between the brain network connectivity with cognitive performance. Fourteen patients with unilateral left MTLE before and after ATL were compared with thirty healthy controls (HCs) on functional connectivity (FC) between resting-state networks (RSNs). The correlation between the neuropsychological tests of patients and abnormal FC was further investigated. When compared with the HCs, patients before surgery showed significantly changed FC between special RSNs. No difference of FC was found between each RSN when patients were compared with the HCs after surgery. Compared with patients before surgery, patients after surgery showed significantly decreased FC between RSNs. Abnormal FC between RSNs significantly correlated with Montreal Cognitive Assessment (MoCA) scores. Our study suggested that dynamic alterations of RSN after ATL in unilateral MTLE may be closely related with seizure generating. However, unchanged FC between RSN before and after ATL may be closely related with cognitive performance. The present findings may help us understand the feature of brain network alterations in patients with left MTLE who became seizure-free following ATL.
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Affiliation(s)
- Chao Zhang
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, PR China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, PR China
| | - Hongyu Yang
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, PR China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, PR China
| | - Chang Liu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, PR China
| | - Guojun Zhang
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, PR China
| | - Nan Chen
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, PR China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, PR China.
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, PR China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, PR China.
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Song X, Roy B, Kang DW, Aysola RS, Macey PM, Woo MA, Yan-Go FL, Harper RM, Kumar R. Altered resting-state hippocampal and caudate functional networks in patients with obstructive sleep apnea. Brain Behav 2018; 8:e00994. [PMID: 29749715 PMCID: PMC5991585 DOI: 10.1002/brb3.994] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 03/29/2018] [Accepted: 04/06/2018] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Brain structural injury and metabolic deficits in the hippocampus and caudate nuclei may contribute to cognitive and emotional deficits found in obstructive sleep apnea (OSA) patients. If such contributions exist, resting-state interactions of these subcortical sites with cortical areas mediating affective symptoms and cognition should be disturbed. Our aim was to examine resting-state functional connectivity (FC) of the hippocampus and caudate to other brain areas in OSA relative to control subjects, and to relate these changes to mood and neuropsychological scores. METHODS We acquired resting-state functional magnetic resonance imaging (fMRI) data from 70 OSA and 89 healthy controls using a 3.0-Tesla magnetic resonance imaging scanner, and assessed psychological and behavioral functions, as well as sleep issues. After standard fMRI data preprocessing, FC maps were generated for bilateral hippocampi and caudate nuclei, and compared between groups (ANCOVA; covariates, age and gender). RESULTS Obstructive sleep apnea subjects showed significantly higher levels of anxiety and depressive symptoms over healthy controls. In OSA subjects, the hippocampus showed disrupted FC with the thalamus, para-hippocampal gyrus, medial and superior temporal gyrus, insula, and posterior cingulate cortex. Left and right caudate nuclei showed impaired FC with the bilateral inferior frontal gyrus and right angular gyrus. In addition, altered limbic-striatal-cortical FC in OSA showed relationships with behavioral and neuropsychological variables. CONCLUSIONS The compromised hippocampal-cortical FC in OSA may underlie depression and anxious mood levels in OSA, while impaired caudate-cortical FC may indicate deficits in reward processing and cognition. These findings provide insights into the neural mechanisms underlying the comorbidity of mood and cognitive deficits in OSA.
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Affiliation(s)
- Xiaopeng Song
- Department of Anesthesiology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Bhaswati Roy
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, USA
| | - Daniel W Kang
- Department of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Ravi S Aysola
- Department of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Paul M Macey
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, USA
| | - Mary A Woo
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, USA
| | - Frisca L Yan-Go
- Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Ronald M Harper
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA, USA.,Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, USA
| | - Rajesh Kumar
- Department of Anesthesiology, University of California at Los Angeles, Los Angeles, CA, USA.,Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, USA.,Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA, USA.,Department of Bioengineering, University of California at Los Angeles, Los Angeles, CA, USA
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29
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Sideman N, Chaitanya G, He X, Doucet G, Kim NY, Sperling MR, Sharan AD, Tracy JI. Task activation and functional connectivity show concordant memory laterality in temporal lobe epilepsy. Epilepsy Behav 2018; 81:70-78. [PMID: 29499551 DOI: 10.1016/j.yebeh.2018.01.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/12/2018] [Accepted: 01/23/2018] [Indexed: 01/21/2023]
Abstract
OBJECTIVE In epilepsy, asymmetries in the organization of mesial temporal lobe (MTL) functions help determine the cognitive risk associated with procedures such as anterior temporal lobectomy. Past studies have investigated the change/shift in a visual episodic memory laterality index (LI) in mesial temporal lobe structures through functional magnetic resonance imaging (fMRI) task activations. Here, we examine whether underlying task-related functional connectivity (FC) is concordant with such standard fMRI laterality measures. METHODS A total of 56 patients with temporal lobe epilepsy (TLE) (Left TLE [LTLE]: 31; Right TLE [RTLE]: 25) and 34 matched healthy controls (HC) underwent fMRI scanning during performance of a scene encoding task (SET). We assessed an activation-based LI of the hippocampal gyrus (HG) and parahippocampal gyrus (PHG) during the SET and its correspondence with task-related FC measures. RESULTS Analyses involving the HG and PHG showed that the patients with LTLE had a consistently higher LI (right-lateralized) than that of the HC and group with RTLE, indicating functional reorganization. The patients with RTLE did not display a reliable contralateral shift away from the pathology, with the mesial structures showing quite distinct laterality patterns (HG, no laterality bias; PHG, no evidence of LI shift). The FC data for the group with LTLE provided confirmation of reorganization effects, revealing that a rightward task LI may be based on underlying connections between several left-sided regions (middle/superior occipital and left medial frontal gyri) and the right PHG. The FCs between the right HG and left anterior cingulate/medial frontal gyri were also observed in LTLE. Importantly, the data demonstrate that the areas involved in the LTLE task activation shift to the right hemisphere showed a corresponding increase in task-related FCs between the hemispheres. SIGNIFICANCE Altered laterality patterns based on mesial temporal lobe epilepsy (MTLE) pathology manifest as several different phenotypes, varying according to side of seizure onset and the specific mesial structures involved. There is good correspondence between task LI activation and FC patterns in the setting of LTLE, suggesting that reliable visual episodic memory reorganization may require both a shift in nodal activation and a change in nodal connectivity with mesial temporal structures involved in memory.
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Affiliation(s)
- Noah Sideman
- Thomas Jefferson University, Department of Neurology, United States
| | - Ganne Chaitanya
- Thomas Jefferson University, Department of Neurology, United States
| | - Xiaosong He
- Thomas Jefferson University, Department of Neurology, United States
| | - Gaelle Doucet
- Icahn School of Medicine at Mount Sinai, Department of Psychiatry, United States
| | - Na Young Kim
- Thomas Jefferson University, Department of Neurology, United States
| | | | - Ashwini D Sharan
- Thomas Jefferson University, Department of Neurosurgery, United States
| | - Joseph I Tracy
- Thomas Jefferson University, Department of Neurology, United States.
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31
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Englot DJ, D'Haese PF, Konrad PE, Jacobs ML, Gore JC, Abou-Khalil BW, Morgan VL. Functional connectivity disturbances of the ascending reticular activating system in temporal lobe epilepsy. J Neurol Neurosurg Psychiatry 2017. [PMID: 28630376 PMCID: PMC5634927 DOI: 10.1136/jnnp-2017-315732] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Seizures in temporal lobe epilepsy (TLE) disturb brain networks and lead to connectivity disturbances. We previously hypothesised that recurrent seizures in TLE may lead to abnormal connections involving subcortical activating structures including the ascending reticular activating system (ARAS), contributing to neocortical dysfunction and neurocognitive impairments. However, no studies of ARAS connectivity have been previously reported in patients with epilepsy. METHODS We used resting-state functional MRI recordings in 27 patients with TLE (67% right sided) and 27 matched controls to examine functional connectivity (partial correlation) between eight brainstem ARAS structures and 105 cortical/subcortical regions. ARAS nuclei included: cuneiform/subcuneiform, dorsal raphe, locus coeruleus, median raphe, parabrachial complex, pontine oralis, pedunculopontine and ventral tegmental area. Connectivity patterns were related to disease and neuropsychological parameters. RESULTS In control subjects, regions showing highest connectivity to ARAS structures included limbic structures, thalamus and certain neocortical areas, which is consistent with prior studies of ARAS projections. Overall, ARAS connectivity was significantly lower in patients with TLE than controls (p<0.05, paired t-test), particularly to neocortical regions including insular, lateral frontal, posterior temporal and opercular cortex. Diminished ARAS connectivity to these regions was related to increased frequency of consciousness-impairing seizures (p<0.01, Pearson's correlation) and was associated with impairments in verbal IQ, attention, executive function, language and visuospatial memory on neuropsychological evaluation (p<0.05, Spearman's rho or Kendell's tau-b). CONCLUSIONS Recurrent seizures in TLE are associated with disturbances in ARAS connectivity, which are part of the widespread network dysfunction that may be related to neurocognitive problems in this devastating disorder.
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Affiliation(s)
- Dario J Englot
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Pierre-Francois D'Haese
- Department of Electrical Engineering, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Peter E Konrad
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Monica L Jacobs
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Bassel W Abou-Khalil
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Victoria L Morgan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Allone C, Lo Buono V, Corallo F, Pisani LR, Pollicino P, Bramanti P, Marino S. Neuroimaging and cognitive functions in temporal lobe epilepsy: A review of the literature. J Neurol Sci 2017; 381:7-15. [DOI: 10.1016/j.jns.2017.08.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 08/02/2017] [Accepted: 08/07/2017] [Indexed: 02/05/2023]
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Simultaneous Intracranial EEG-fMRI Shows Inter-Modality Correlation in Time-Resolved Connectivity Within Normal Areas but Not Within Epileptic Regions. Brain Topogr 2017; 30:639-655. [DOI: 10.1007/s10548-017-0551-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/24/2017] [Indexed: 12/11/2022]
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34
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Relationship between resting state functional magnetic resonance imaging and memory function in mesial temporal lobe epilepsy. J Neurol Sci 2017; 372:117-125. [DOI: 10.1016/j.jns.2016.10.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/27/2016] [Accepted: 10/27/2016] [Indexed: 11/23/2022]
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35
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Grewe P, Nikstat A, Koch O, Koch-Stoecker S, Bien C. Subjective memory complaints in patients with epilepsy: The role of depression, psychological distress, and attentional functions. Epilepsy Res 2016; 127:78-86. [DOI: 10.1016/j.eplepsyres.2016.08.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 06/21/2016] [Accepted: 08/17/2016] [Indexed: 01/28/2023]
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36
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Robinson LF, He X, Barnett P, Doucet GE, Sperling MR, Sharan A, Tracy JI. The Temporal Instability of Resting State Network Connectivity in Intractable Epilepsy. Hum Brain Mapp 2016; 38:528-540. [PMID: 27628031 DOI: 10.1002/hbm.23400] [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: 05/04/2016] [Revised: 08/11/2016] [Accepted: 08/30/2016] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Focal epilepsies, such as temporal lobe epilepsy (TLE), are known to disrupt network activity in areas outside the epileptogenic zone [Tracy et al., 2015]. We devised a measure of temporal instability of resting state functional connectivity (FC), capturing temporal variations of BOLD correlations between brain regions that is less confounded than the "sliding window" approach common in the literature. METHODS We investigated healthy controls and unilateral TLE patients (right and left seizure focus groups), utilizing group ICA to identify the default mode network (DMN), a network associated with episodic memory, a key cognitive deficit in TLE. Our instability analyses focused on: (1) connectivity between DMN region pairs, both within and between TLE patients and matched controls, (2) whole brain group differences between region pairs ipsilateral or contralateral to the epileptogenic temporal lobe. RESULTS For both the whole brain and a more focused analysis of DMN region pairs, temporal stability appears to characterize the healthy brain. The TLE patients displayed more FC instability compared to controls, with this instability more pronounced for the right TLE patients. SIGNIFICANCE Our findings challenge the view that the resting state signal is stable over time, providing a measure of signal coherence change that may generate insights into the temporal components of network organization. The precuneus was the region within the DMN consistently expressing this instability, suggesting this region plays a key role in large scale temporal dynamics of the DMN, with such dynamics disrupted in TLE, putting key cognitive functions at risk. Hum Brain Mapp 38:528-540, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Lucy F Robinson
- Department of Epidemiology and Biostatistics, Drexel University, Philadelphia, Pennsylvania
| | - Xiaosong He
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Paul Barnett
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Gaёlle E Doucet
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ashwini Sharan
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Joseph I Tracy
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania
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37
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Englot DJ, Konrad PE, Morgan VL. Regional and global connectivity disturbances in focal epilepsy, related neurocognitive sequelae, and potential mechanistic underpinnings. Epilepsia 2016; 57:1546-1557. [PMID: 27554793 DOI: 10.1111/epi.13510] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2016] [Indexed: 12/19/2022]
Abstract
Epilepsy is among the most common brain network disorders, and it is associated with substantial morbidity and increased mortality. Although focal epilepsy was traditionally considered a regional brain disorder, growing evidence has demonstrated widespread network alterations in this disorder that extend beyond the epileptogenic zone from which seizures originate. The goal of this review is to summarize recent investigations examining functional and structural connectivity alterations in focal epilepsy, including neuroimaging and electrophysiologic studies utilizing model-based or data-driven analytic methods. A significant subset of studies in both mesial temporal lobe epilepsy and focal neocortical epilepsy have demonstrated patterns of increased connectivity related to the epileptogenic zone, coupled with decreased connectivity in widespread distal networks. Connectivity patterns appear to be related to the duration and severity of disease, suggesting progressive connectivity reorganization in the setting of recurrent seizures over time. Global resting-state connectivity disturbances in focal epilepsy have been linked to neurocognitive problems, including memory and language disturbances. Although it is possible that increased connectivity in a particular brain region may enhance the propensity for seizure generation, it is not clear if global reductions in connectivity represent the damaging consequences of recurrent seizures, or an adaptive mechanism to prevent seizure propagation away from the epileptogenic zone. Overall, studying the connectome in focal epilepsy is a critical endeavor that may lead to improved strategies for epileptogenic-zone localization, surgical outcome prediction, and a better understanding of the neuropsychological implications of recurrent seizures.
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Affiliation(s)
- Dario J Englot
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A..
| | - Peter E Konrad
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A
| | - Victoria L Morgan
- Department of Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, U.S.A
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Chengyang L, Daqing H, Jianlin Q, Haisheng C, Qingqing M, Jin W, Jiajia L, Enmao Y, Yongcong S, Xi Z. Short-term memory deficits correlate with hippocampal-thalamic functional connectivity alterations following acute sleep restriction. Brain Imaging Behav 2016; 11:954-963. [DOI: 10.1007/s11682-016-9570-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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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Lopour BA, Staba RJ, Stern JM, Fried I, Ringach DL. Characterization of long-range functional connectivity in epileptic networks by neuronal spike-triggered local field potentials. J Neural Eng 2016; 13:026031. [PMID: 26975603 DOI: 10.1088/1741-2560/13/2/026031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Quantifying the relationship between microelectrode-recorded multi-unit activity (MUA) and local field potentials (LFPs) in distinct brain regions can provide detailed information on the extent of functional connectivity in spatially widespread networks. These methods are common in studies of cognition using non-human animal models, but are rare in humans. Here we applied a neuronal spike-triggered impulse response to electrophysiological recordings from the human epileptic brain for the first time, and we evaluate functional connectivity in relation to brain areas supporting the generation of seizures. APPROACH Broadband interictal electrophysiological data were recorded from microwires adapted to clinical depth electrodes that were implanted bilaterally using stereotactic techniques in six presurgical patients with medically refractory epilepsy. MUA and LFPs were isolated in each microwire, and we calculated the impulse response between the MUA on one microwire and the LFPs on a second microwire for all possible MUA/LFP pairs. Results were compared to clinical seizure localization, including sites of seizure onset and interictal epileptiform discharges. MAIN RESULTS We detected significant interictal long-range functional connections in each subject, in some cases across hemispheres. Results were consistent between two independent datasets, and the timing and location of significant impulse responses reflected anatomical connectivity. However, within individual subjects, the spatial distribution of impulse responses was unique. In two subjects with clear seizure localization and successful surgery, the epileptogenic zone was associated with significant impulse responses. SIGNIFICANCE The results suggest that the spike-triggered impulse response can provide valuable information about the neuronal networks that contribute to seizures using only interictal data. This technique will enable testing of specific hypotheses regarding functional connectivity in epilepsy and the relationship between functional properties and imaging findings. Beyond epilepsy, we expect that the impulse response could be more broadly applied as a measure of long-range functional connectivity in studies of cognition.
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Affiliation(s)
- Beth A Lopour
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA
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Li H, Fan W, Yang J, Song S, Liu Y, Lei P, Shrestha L, Mella G, Chen W, Xu H. Asymmetry in cross-hippocampal connectivity in unilateral mesial temporal lobe epilepsy. Epilepsy Res 2015; 118:14-21. [PMID: 26561924 DOI: 10.1016/j.eplepsyres.2015.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 09/15/2015] [Accepted: 10/25/2015] [Indexed: 01/06/2023]
Abstract
Mesial temporal lobe epilepsy (mTLE) is mostly characterized by hippocampal sclerosis (HS) changes. Although considerable progress has been made in understanding the altered functional network of mTLE patients, whether one side of the abnormal hippocampal (HP) structure will affect the other healthy side of the hippocampal network is still unclear. Here, we used a seed-based method to explore the commonly alterative hippocampal network in mTLE patients by comparing the bilateral hippocampal network of unilateral mTLE patients with healthy control participants. We observed that both sides of the hippocampal network in unilateral mTLE patients were changed independent of the affected or "healthy" side, which may suggest a common plasticity network for both sides of hippocampal sclerosis mesial temporal lobe epilepsy patients. Furthermore, using the HP as the ROI, we found that the functional connectivity of the intra-HP in the left mTLE-HS group was moderately positively correlated with the duration of the disease, while a strong negative correlation between functional connectivity of the intra-HP and duration were detected in the right mTLE-HS group, which suggested that it was easier for the right HP than the left HP to communicate with the contralateral HP according to the progression of mTLE disease because the hippocampus plays different roles in the communication and compensatory mechanism associated with the contralateral side of the hemisphere. We hope that this potential relevance may help us to better characterize mTLE with hippocampal sclerosis and ultimately assist in providing a better diagnosis and more accurate invasive treatments of mTLE.
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Affiliation(s)
- Hong Li
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Wenliang Fan
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Jie Yang
- Department of Communication Sciences and Disorders, Massachusetts General Hospital Institute of Health Professions, Boston, MA, USA.
| | - Shuyan Song
- School of Life Science and Technology, Key Laboratory of Image Processing and Intelligent Control of Education Ministry of China, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Yuan Liu
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Ping Lei
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Lochan Shrestha
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Grace Mella
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Wei Chen
- Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Radiology and Medical Imaging Center, The First People's Hospital of Yibin, Sichuan 644000, China.
| | - Haibo Xu
- Department of Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China.
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Jin SH, Chung CK. Functional substrate for memory function differences between patients with left and right mesial temporal lobe epilepsy associated with hippocampal sclerosis. Epilepsy Behav 2015; 51:251-8. [PMID: 26300534 DOI: 10.1016/j.yebeh.2015.07.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/24/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Little is known about the functional substrate for memory function differences in patients with left or right mesial temporal lobe epilepsy (mTLE) associated with hippocampal sclerosis (HS) from an electrophysiological perspective. To characterize these differences, we hypothesized that hippocampal theta connectivity in the resting-state might be different between patients with left and right mTLE with HS and be correlated with memory performance. METHODS Resting-state hippocampal theta connectivity, identified via whole-brain magnetoencephalography, was evaluated. Connectivity and memory function in 41 patients with mTLE with HS (left mTLE=22; right mTLE=19) were compared with those in 46 age-matched healthy controls and 28 patients with focal cortical dysplasia (FCD) but without HS. RESULTS Connectivity between the right hippocampus and the left middle frontal gyrus was significantly stronger in patients with right mTLE than in patients with left mTLE. Moreover, this connectivity was positively correlated with delayed verbal recall and recognition scores in patients with mTLE. Patients with left mTLE had greater delayed recall impairment than patients with right mTLE and FCD. Similarly, delayed recognition performance was worse in patients with left mTLE than in patients with right mTLE and FCD. No significant differences in memory function between patients with right mTLE and FCD were detected. Patients with right mTLE showed significantly stronger hippocampal theta connectivity between the right hippocampus and left middle frontal gyrus than patients with FCD and left mTLE. CONCLUSION Our results suggest that right hippocampal-left middle frontal theta connectivity could be a functional substrate that can account for differences in memory function between patients with left and right mTLE. This functional substrate might be related to different compensatory mechanisms against the structural hippocampal lesions in left and right mTLE groups. Given the positive correlation between connectivity and delayed verbal memory function, hemispheric-specific hippocampal-frontal theta connectivity assessment could be useful as an electrophysiological indicator of delayed verbal memory function in patients with mTLE with HS.
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Affiliation(s)
- Seung-Hyun Jin
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Chun Kee Chung
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Neurosurgery, Seoul National University Hospital, Seoul, Republic of Korea; Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea.
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Ji GJ, Zhang Z, Xu Q, Wei W, Wang J, Wang Z, Yang F, Sun K, Jiao Q, Liao W, Lu G. Connectome Reorganization Associated With Surgical Outcome in Temporal Lobe Epilepsy. Medicine (Baltimore) 2015; 94:e1737. [PMID: 26448031 PMCID: PMC4616737 DOI: 10.1097/md.0000000000001737] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
To identify the distinct pattern of anatomical network reorganization in surgically refractory mesial temporal lobe epilepsy (MTLE) patients using a longitudinal design. We collected longitudinal diffusion-weighted images of 19 MTLE patients before and after anterior temporal lobectomy. Patients were classified as seizure-free (SF) or nonseizure-free (NSF) at least 1 year after surgery. We constructed whole-brain anatomical networks derived from white matter tractography and evaluated network connectivity measures by graph theoretical analysis. The reorganization trajectories of network measures in SF and NSF patients were investigated by two-way mixed analysis of variance, with factors "group" (SF vs NSF) and "treatment" (presurgery vs postsurgery). Widespread brain structures showed opposite reorganization trajectories in FS and NSF groups (interaction effect). Most of them showed group difference before surgery and then converge after surgery, suggesting that surgery remodeled these structures into a similar status. Conversly, contralateral amygdala-planum-temporale and thalamic-parietal tracts showed higher connectivity strength in NSF than in SF patients after surgery, indicating maladaptive neuroplastic responses to surgery in NSF patients. Our findings suggest that surgical outcomes are associated not only with the preoperative pattern of anatomical connectivity, but also with connectome reconfiguration following surgery. The reorganization of contralateral temporal lobe and corticothalamic tracts may be particularly important for seizure control in MTLE.
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Affiliation(s)
- Gong-Jun Ji
- From the Laboratory of Cognitive Neuropsychology, Department of Medical Psychology, Anhui Medical University, Hefei (G-JJ); Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University (G-JJ, JW, WL); Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou (G-JJ, JW, WL); Department of Medical Imaging, Jinling Hospital, Nanjing University School of Medicine (ZZ, QX, WW, GL); Department of Medical Imaging, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School (ZW); Department of Neurology, Jinling Hospital (FY); Department of Neurosurgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing (KS); Department of Radiology, Taishan Medical University, Tai'an (QJ); and Key Laboratory for Neuroinformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China (WL)
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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: 177] [Impact Index Per Article: 19.7] [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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Douw L, Leveroni CL, Tanaka N, Emerton BC, Cole AC, Reinsberger C, Stufflebeam SM. Loss of resting-state posterior cingulate flexibility is associated with memory disturbance in left temporal lobe epilepsy. PLoS One 2015; 10:e0131209. [PMID: 26110431 PMCID: PMC4481466 DOI: 10.1371/journal.pone.0131209] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 05/30/2015] [Indexed: 01/08/2023] Open
Abstract
The association between cognition and resting-state fMRI (rs-fMRI) has been the focus of many recent studies, most of which use stationary connectivity. The dynamics or flexibility of connectivity, however, may be seminal for understanding cognitive functioning. In temporal lobe epilepsy (TLE), stationary connectomic correlates of impaired memory have been reported mainly for the hippocampus and posterior cingulate cortex (PCC). We therefore investigate resting-state and task-based hippocampal and PCC flexibility in addition to stationary connectivity in left TLE (LTLE) patients. Sixteen LTLE patients were analyzed with respect to rs-fMRI and task-based fMRI (t-fMRI), and underwent clinical neuropsychological testing. Flexibility of connectivity was calculated using a sliding-window approach by determining the standard deviation of Fisher-transformed Pearson correlation coefficients over all windows. Stationary connectivity was also calculated. Disturbed memory was operationalized as having at least one memory subtest score equal to or below the 5th percentile compared to normative data. Lower PCC flexibility, particularly in the contralateral (i.e. right) hemisphere, was found in memory-disturbed LTLE patients, who had up to 22% less flexible connectivity. No significant group differences were found with respect to hippocampal flexibility, stationary connectivity during both rs-fMRI and t-fMRI, or flexibility during t-fMRI. Contralateral resting-state PCC flexibility was able to classify all but one patient with respect to their memory status (94% accuracy). Flexibility of the PCC during rest relates to memory functioning in LTLE patients. Loss of flexible connectivity to the rest of the brain originating from the PCC, particularly contralateral to the seizure focus, is able to discern memory disturbed patients from their preserved counterparts. This study indicates that the dynamics of resting-state connectivity are associated with cognitive status of LTLE patients, rather than stationary connectivity.
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Affiliation(s)
- Linda Douw
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America
- Department of Radiology, Harvard Medical School, Boston, MA, United States of America
- Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands
- * E-mail:
| | - Catherine L. Leveroni
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, United States of America
| | - Naoaki Tanaka
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America
- Department of Radiology, Harvard Medical School, Boston, MA, United States of America
| | - Britt C. Emerton
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, United States of America
| | - Andrew C. Cole
- Department of Neurology, Massachusetts General Hospital, Boston, MA, United States of America
| | - Claus Reinsberger
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA, United States of America
- Institute of Sports Medicine, Faculty of Science, University of Paderborn, Paderborn, Germany
| | - Steven M. Stufflebeam
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America
- Department of Radiology, Harvard Medical School, Boston, MA, United States of America
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Ridley BGY, Rousseau C, Wirsich J, Le Troter A, Soulier E, Confort-Gouny S, Bartolomei F, Ranjeva JP, Achard S, Guye M. Nodal approach reveals differential impact of lateralized focal epilepsies on hub reorganization. Neuroimage 2015; 118:39-48. [PMID: 26070261 DOI: 10.1016/j.neuroimage.2015.05.096] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 04/30/2015] [Accepted: 05/21/2015] [Indexed: 02/07/2023] Open
Abstract
The impact of the hemisphere affected by impairment in models of network disease is not fully understood. Among such models, focal epilepsies are characterised by recurrent seizures generated in epileptogenic areas also responsible for wider network dysfunction between seizures. Previous work focusing on functional connectivity within circumscribed networks suggests a divergence of network integrity and compensatory capacity between epilepsies as a function of the laterality of seizure onset. We evaluated the ability of complex network theory to reveal changes in focal epilepsy in global and nodal parameters using graph theoretical analysis of functional connectivity data obtained with resting-state fMRI. Graphs of functional connectivity networks were derived from 19 right and 13 left focal epilepsy patients and 15 controls. Topological metrics (degree, local efficiency, global efficiency and modularity) were computed for a whole-brain, atlas-defined network. We also calculated a hub disruption index for each graph metric, measuring the capacity of the brain network to demonstrate increased connectivity in some nodes for decreased connectivity in others. Our data demonstrate that the patient group as a whole is characterised by network-wide pattern of reorganization, even while global parameters fail to distinguish between groups. Furthermore, multiple metrics indicate that epilepsies with differently lateralized epileptic networks are asymmetric in their burden on functional brain networks; with left epilepsy patients being characterised by reduced efficiency and modularity, while in right epilepsy patients we provide the first evidence that functional brain networks are characterised by enhanced connectivity and efficiency at some nodes whereas reduced in others.
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Affiliation(s)
- Ben Gendon Yeshe Ridley
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Celia Rousseau
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Jonathan Wirsich
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Arnaud Le Troter
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Elisabeth Soulier
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Sylvianne Confort-Gouny
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Fabrice Bartolomei
- APHM, Hôpital de la Timone, Service de Neurophysiologie Clinique, 13005 Marseille, France; Aix-Marseille Université, INSERM, Institut de Neuroscience des Systèmes U1106, 13005 Marseille, France.
| | - Jean-Philippe Ranjeva
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
| | - Sophie Achard
- Centre National de la Recherche Scientifique, Grenoble Image Parole Signal Automatique, 38402 Grenoble, France.
| | - Maxime Guye
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, 13005 Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, 13005 Marseille, France.
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Englot DJ, Hinkley LB, Kort NS, Imber BS, Mizuiri D, Honma SM, Findlay AM, Garrett C, Cheung PL, Mantle M, Tarapore PE, Knowlton RC, Chang EF, Kirsch HE, Nagarajan SS. Global and regional functional connectivity maps of neural oscillations in focal epilepsy. Brain 2015; 138:2249-62. [PMID: 25981965 DOI: 10.1093/brain/awv130] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 03/19/2015] [Indexed: 01/27/2023] Open
Abstract
Intractable focal epilepsy is a devastating disorder with profound effects on cognition and quality of life. Epilepsy surgery can lead to seizure freedom in patients with focal epilepsy; however, sometimes it fails due to an incomplete delineation of the epileptogenic zone. Brain networks in epilepsy can be studied with resting-state functional connectivity analysis, yet previous investigations using functional magnetic resonance imaging or electrocorticography have produced inconsistent results. Magnetoencephalography allows non-invasive whole-brain recordings, and can be used to study both long-range network disturbances in focal epilepsy and regional connectivity at the epileptogenic zone. In magnetoencephalography recordings from presurgical epilepsy patients, we examined: (i) global functional connectivity maps in patients versus controls; and (ii) regional functional connectivity maps at the region of resection, compared to the homotopic non-epileptogenic region in the contralateral hemisphere. Sixty-one patients were studied, including 30 with mesial temporal lobe epilepsy and 31 with focal neocortical epilepsy. Compared with a group of 31 controls, patients with epilepsy had decreased resting-state functional connectivity in widespread regions, including perisylvian, posterior temporo-parietal, and orbitofrontal cortices (P < 0.01, t-test). Decreased mean global connectivity was related to longer duration of epilepsy and higher frequency of consciousness-impairing seizures (P < 0.01, linear regression). Furthermore, patients with increased regional connectivity within the resection site (n = 24) were more likely to achieve seizure postoperative seizure freedom (87.5% with Engel I outcome) than those with neutral (n = 15, 64.3% seizure free) or decreased (n = 23, 47.8% seizure free) regional connectivity (P < 0.02, chi-square). Widespread global decreases in functional connectivity are observed in patients with focal epilepsy, and may reflect deleterious long-term effects of recurrent seizures. Furthermore, enhanced regional functional connectivity at the area of resection may help predict seizure outcome and aid surgical planning.
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Affiliation(s)
- Dario J Englot
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 2 Department of Neurological Surgery, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Leighton B Hinkley
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Naomi S Kort
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Brandon S Imber
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 2 Department of Neurological Surgery, University of California, San Francisco, California, USA
| | - Danielle Mizuiri
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Susanne M Honma
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Anne M Findlay
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Coleman Garrett
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Paige L Cheung
- 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Mary Mantle
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Phiroz E Tarapore
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 2 Department of Neurological Surgery, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Robert C Knowlton
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA 4 Department of Neurology, University of California, San Francisco, California, USA
| | - Edward F Chang
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 2 Department of Neurological Surgery, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Heidi E Kirsch
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA 4 Department of Neurology, University of California, San Francisco, California, USA
| | - Srikantan S Nagarajan
- 1 UCSF Comprehensive Epilepsy Centre, University of California, San Francisco, California, USA 3 Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
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van Graan LA, Lemieux L, Chaudhary UJ. Methods and utility of EEG-fMRI in epilepsy. Quant Imaging Med Surg 2015; 5:300-12. [PMID: 25853087 DOI: 10.3978/j.issn.2223-4292.2015.02.04] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/22/2015] [Indexed: 12/13/2022]
Abstract
Brain activity data in general and more specifically in epilepsy can be represented as a matrix that includes measures of electrophysiology, anatomy and behaviour. Each of these sub-matrices has a complex interaction depending upon the brain state i.e., rest, cognition, seizures and interictal periods. This interaction presents significant challenges for interpretation but also potential for developing further insights into individual event types. Successful treatments in epilepsy hinge on unravelling these complexities, and also on the sensitivity and specificity of methods that characterize the nature and localization of underlying physiological and pathological networks. Limitations of pharmacological and surgical treatments call for refinement and elaboration of methods to improve our capability to localise the generators of seizure activity and our understanding of the neurobiology of epilepsy. Simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI), by potentially circumventing some of the limitations of EEG in terms of sensitivity, can allow the mapping of haemodynamic networks over the entire brain related to specific spontaneous and triggered epileptic events in humans, and thereby provide new localising information. In this work we review the published literature, and discuss the methods and utility of EEG-fMRI in localising the generators of epileptic activity. We draw on our experience and that of other groups, to summarise the spectrum of information provided by an increasing number of EEG-fMRI case-series, case studies and group studies in patients with epilepsy, for its potential role to elucidate epileptic generators and networks. We conclude that EEG-fMRI provides a multidimensional view that contributes valuable clinical information to localize the epileptic focus with potential important implications for the surgical treatment of some patients with drug-resistant epilepsy, and insights into the resting state and cognitive network dynamics.
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Affiliation(s)
- Louis André van Graan
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK ; 2 MRI Unit, Epilepsy Society, Chalfont St. Peter SL9 0RJ, UK
| | - Louis Lemieux
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK ; 2 MRI Unit, Epilepsy Society, Chalfont St. Peter SL9 0RJ, UK
| | - Umair Javaid Chaudhary
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK ; 2 MRI Unit, Epilepsy Society, Chalfont St. Peter SL9 0RJ, UK
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Chen XM, Huang DH, Chen ZR, Ye W, Lv ZX, Zheng JO. Temporal lobe epilepsy: decreased thalamic resting-state functional connectivity and their relationships with alertness performance. Epilepsy Behav 2015; 44:47-54. [PMID: 25622022 DOI: 10.1016/j.yebeh.2014.12.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 12/20/2022]
Abstract
OBJECTIVES Studies have provided evidence regarding the pathology of the thalamus in patients with temporal lobe epilepsy (TLE). The thalamus, particularly the right thalamus, is one of the subcortical structures that are most uniformly accepted as being significantly involved in alertness. Moreover, alertness impairment in epilepsy has been reported. This study aimed to investigate alterations in thalamic resting-state functional connectivity (FC) and their relationships with alertness performance in patients with TLE; an issue that has not yet been addressed. METHODS A total of 15 patients with right TLE (rTLE) and 16 healthy controls were recruited for the present study. All of the participants underwent a resting-state functional magnetic resonance imaging (fMRI) scan and the attention network test (ANT). Whole-brain voxel-wise FC analyses were applied to extract the thalamic resting-state functional networks in the patients with rTLE and healthy controls, and the differences between the two groups were evaluated. Correlation analyses were employed to examine the relationships between alterations in thalamic FC and alertness performance in patients with rTLE. RESULTS Compared to the healthy controls, the FC within and between the bilateral thalamus was decreased in the patients with rTLE. Moreover, in the patient group, the bilateral anterior cingulate cortex (ACC) and subcortical regions, including the bilateral brainstem, cerebellum, putamen, right caudate nucleus, and amygdala, exhibited decreased FC with the ipsilateral thalamus (p<0.05, AlphaSim corrected, cluster size>44) but not with the contralateral thalamus (p<0.05, AlphaSim corrected, cluster size>43). The intrinsic and phasic alertness performances of the patients were impaired (p=0.001 and p<0.001, respectively) but not correlated with decreased thalamic FC. Meanwhile, the alertness performance was not altered in right TLE but was negatively correlated with decreased thalamic FC with ACC (p<0.05). CONCLUSIONS Our findings highlight the functional importance of the thalamus in TLE pathology and suggest that damage to the thalamic resting-state functional networks, particularly ipsilateral to the epileptogenic focus, is present in patients with TLE.
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Affiliation(s)
- Xue-Mei Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Dong-Hong Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Zi-Rong Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Wei Ye
- Department of Radiology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Zong-Xia Lv
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Jin-Ou Zheng
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
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Douw L, DeSalvo MN, Tanaka N, Cole AJ, Liu H, Reinsberger C, Stufflebeam SM. Dissociated multimodal hubs and seizures in temporal lobe epilepsy. Ann Clin Transl Neurol 2015; 2:338-52. [PMID: 25909080 PMCID: PMC4402080 DOI: 10.1002/acn3.173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 12/22/2014] [Accepted: 12/22/2014] [Indexed: 11/16/2022] Open
Abstract
Objective Brain connectivity at rest is altered in temporal lobe epilepsy (TLE), particularly in “hub” areas such as the posterior default mode network (DMN). Although both functional and anatomical connectivity are disturbed in TLE, the relationships between measures as well as to seizure frequency remain unclear. We aim to clarify these associations using connectivity measures specifically sensitive to hubs. Methods Connectivity between 1000 cortical surface parcels was determined in 49 TLE patients and 23 controls with diffusion and resting-state functional magnetic resonance imaging. Two types of hub connectivity were investigated across multiple brain modules (the DMN, motor system, etcetera): (1) within-module connectivity (a measure of local importance that assesses a parcel's communication level within its own subnetwork) and (2) between-module connectivity (a measure that assesses connections across multiple modules). Results In TLE patients, there was lower overall functional integrity of the DMN as well as an increase in posterior hub connections with other modules. Anatomical between-module connectivity was globally decreased. Higher DMN disintegration (DD) coincided with higher anatomical between-module connectivity, whereas both were associated with increased seizure frequency. DD related to seizure frequency through mediating effects of anatomical connectivity, but seizure frequency also correlated with anatomical connectivity through DD, indicating a complex interaction between multimodal networks and symptoms. Interpretation We provide evidence for dissociated anatomical and functional hub connectivity in TLE. Moreover, shifts in functional hub connections from within to outside the DMN, an overall loss of integrative anatomical communication, and the interaction between the two increase seizure frequency.
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Affiliation(s)
- Linda Douw
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts ; Department of Anatomy and Neurosciences, VU University Medical Center Amsterdam, The Netherlands
| | - Matthew N DeSalvo
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts
| | - Naoaki Tanaka
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts
| | - Andrew J Cole
- Department of Neurology, Massachusetts General Hospital Boston, Massachusetts
| | - Hesheng Liu
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts
| | - Claus Reinsberger
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Neurology, Brigham and Women's Hospital Boston, Massachusetts
| | - Steven M Stufflebeam
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts
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