Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy

Haneef, Zulfi; Lenartowicz, Agatha; Yeh, Hsiang J.; Engel, Jerome; Stern, John M.

doi:10.3791/51442

Cited by 30 publications

(28 citation statements)

References 42 publications

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“…In addition, the pattern of WM diffusivity alterations found in our sample group could play a significant role in the widespread decrease in connectivity found in MTLE patients (Englot et al, 2015, Haneef et al, 2014, Voets et al, 2012). Previous studies have reported decreased connectivity in MTLE in bilateral posterior temporal and parieto-occipital cortices, perisylvian region, lateral and medial frontal neocortex, posterior cingulum/precuneus and insular cortex (Englot et al, 2015, Haneef et al, 2014, Voets et al, 2012).…”

Section: Discussionmentioning

confidence: 64%

“…Previous studies have reported decreased connectivity in MTLE in bilateral posterior temporal and parieto-occipital cortices, perisylvian region, lateral and medial frontal neocortex, posterior cingulum/precuneus and insular cortex (Englot et al, 2015, Haneef et al, 2014, Voets et al, 2012). The decrease in connectivity may account for the deleterious effects of epilepsy including gray matter atrophy, cortical hypometabolism, neuropsychological deficits, and cognitive impairment (Thom, 2014).…”

Section: Discussionmentioning

confidence: 90%

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Combined 18F-FDG-PET and diffusion tensor imaging in mesial temporal lobe epilepsy with hippocampal sclerosis

Aparicio¹,

Carreño

Bargalló

et al. 2016

NeuroImage: Clinical

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ObjectivesSeveral studies using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) or diffusion tensor imaging (DTI) have found both temporal and extratemporal abnormalities in patients with mesial temporal lobe epilepsy with ipsilateral hippocampal sclerosis (MTLE-HS), but data are lacking about the findings of both techniques in the same patients. We aimed to determine whether the extent of 18F-FDG-PET hypometabolism is related to DTI abnormalities.MethodsTwenty-one patients with MTLE-HS underwent comprehensive preoperative evaluation; 18 (86%) of these underwent epilepsy surgery. We analyzed and compared the pattern of white matter (WM) alterations on DTI and cortical hypometabolism on 18F-FDG-PET.ResultsWe found widespread temporal and extratemporal 18F-FDG-PET and DTI abnormalities. Patterns of WM abnormalities and cortical glucose hypometabolism involved similar brain regions, being more extensive in the left than the right MTLE-HS. We classified patients into three groups according to temporal 18F-FDG-PET patterns: hypometabolism restricted to the anterior third (n = 7), hypometabolism extending to the middle third (n = 7), and hypometabolism extending to the posterior third (n = 7). Patients with anterior temporal hypometabolism showed DTI abnormalities in anterior association and commissural tracts while patients with posterior hypometabolism showed WM alterations in anterior and posterior tracts.ConclusionsPatients with MTLE-HS have widespread metabolic and microstructural abnormalities that involve similar regions. The distribution patterns of these gray and white matter abnormalities differ between patients with left or right MTLE, but also with the extent of the 18F-FDG-PET hypometabolism along the epileptogenic temporal lobe. These findings suggest a variable network involvement among patients with MTLE-HS.

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Section: Discussionmentioning

confidence: 64%

Section: Discussionmentioning

confidence: 90%

Combined 18F-FDG-PET and diffusion tensor imaging in mesial temporal lobe epilepsy with hippocampal sclerosis

Aparicio¹,

Carreño

Bargalló

et al. 2016

NeuroImage: Clinical

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“…Several studies have reported disrupted functional connectivity in resting-state functional connectivity in patients with epilepsy (Englot et al, 2015, Haneef et al, 2014a, Luo et al, 2011, Maneshi et al, 2014, Voets et al, 2012). More specifically, works employing the complex network analysis approach have shown increased characteristic path lengths (Horstmann et al, 2010, Chiang and Haneef, 2014, Otte et al, 2012, Vlooswijk et al, 2011) in epilepsy in fMRI as well as in white matter studies, which is in alignment with our results, and confirms the overall disruption of functional connectivity.…”

Section: Discussionmentioning

confidence: 99%

“…Even though many studies have shown disruptions in brain connectivity caused by epilepsy (Englot et al, 2015, Haneef et al, 2014a, Luo et al, 2011, Maneshi et al, 2014, Voets et al, 2012), the mechanisms by which the subcortical structures are related to the cortical epileptic processes are largely unknown. We hypothesize that the BG-thalamic system might modulate large scale cortical networks and this modulation might be disturbed in epilepsy.…”

Section: Introductionmentioning

confidence: 99%

Large-scale cortico-subcortical functional networks in focal epilepsies: The role of the basal ganglia

Výtvarová

Mareček

Fousek

et al. 2017

NeuroImage: Clinical

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ObjectivesThe aim was to describe the contribution of basal ganglia (BG) thalamo-cortical circuitry to the whole-brain functional connectivity in focal epilepsies.MethodsInterictal resting-state fMRI recordings were acquired in 46 persons with focal epilepsies. Of these 46, 22 had temporal lobe epilepsy: 9 left temporal (LTLE), 13 right temporal (RTLE); 15 had frontal lobe epilepsy (FLE); and 9 had parietal/occipital lobe epilepsy (POLE). There were 20 healthy controls. The complete weighted network was analyzed based on correlation matrices of 90 and 194 regions. The network topology was quantified on a global and regional level by measures based on graph theory, and connection-level changes were analyzed by the partial least square method.ResultsIn all patient groups except RTLE, the shift of the functional network topology away from random was observed (normalized clustering coefficient and characteristic path length were higher in patient groups than in controls). Links contributing to this change were found in the cortico-subcortical connections. Weak connections (low correlations) consistently contributed to this modification of the network. The importance of regions changed: decreases in the subcortical areas and both decreases and increases in the cortical areas were observed in node strength, clustering coefficient and eigenvector centrality in patient groups when compared to controls. Node strength decreases of the basal ganglia, i.e. the putamen, caudate, and pallidum, were displayed in LTLE, FLE, and POLE. The connectivity within the basal ganglia–thalamus circuitry was not disturbed; the disturbance concerned the connectivity between the circuitry and the cortex.SignificanceFocal epilepsies affect large-scale brain networks beyond the epileptogenic zones. Cortico-subcortical functional connectivity disturbance was displayed in LTLE, FLE, and POLE. Significant changes in the resting-state functional connectivity between cortical and subcortical structures suggest an important role of the BG and thalamus in focal epilepsies.

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“…Resting-state studies have described functional connectivity abnormalities in several cognitive networks in epilepsy such as the well known default-mode network (DMN) [30,31], and its subdivisions [32], in addition to attentional [33], language [34,35], and visuospatial working memory [36] networks putting at risk a wide range of neurocognitive and affective functions.…”

Section: Resting-state Functional Connectivity Reveals Neurocognitivementioning

confidence: 99%

Resting-state functional connectivity in epilepsy

Tracy

Doucet²

2015

Current Opinion in Neurology

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The role of rsFC remains limited in most clinical settings, but shows great promise for identifying epileptic circuits and foci, predicting outcomes following surgery, and explaining cognitive deficits and psychiatric symptoms of epilepsy. RsFC has demonstrated that even focal epilepsies constitute a network and brain systems disorder. By providing a tool to both identify and characterize the brain network impact of epileptiform activity, rsFC can make a strong contribution to presurgical algorithms in epilepsy.

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Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy

Cited by 30 publications

References 42 publications

Combined 18F-FDG-PET and diffusion tensor imaging in mesial temporal lobe epilepsy with hippocampal sclerosis

Combined 18F-FDG-PET and diffusion tensor imaging in mesial temporal lobe epilepsy with hippocampal sclerosis

Large-scale cortico-subcortical functional networks in focal epilepsies: The role of the basal ganglia

Resting-state functional connectivity in epilepsy

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