Temporal lobe epilepsy shows divergent functional connectivity patterns in different thalamic nuclei

2020 ◽  
Author(s):  
Rong Li ◽  
Leiyao Zhang ◽  
Danni Guo ◽  
Ting Zou ◽  
Xuyang Wang ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Thalamic Nuclei ◽  
Connectivity Patterns

scholarly journals Thalamic Arousal Network Disturbances in Temporal Lobe Epilepsy and Improvement After Surgery

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Hernán F J González ◽  
Srijata Chakravorti ◽  
Sarah E Goodale ◽  
Kanupriya Gupta ◽  
Daniel O Claassen ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epilepsy Surgery ◽  
Occipital Lobe ◽  
Visuospatial Attention ◽  
Partial Recovery ◽  
Thalamic Nuclei ◽  
Spearman's Rho ◽  
Spearman’S Rho

Abstract INTRODUCTION The effects of temporal lobe epilepsy (TLE) on subcortical arousal structures remain incompletely understood. Here we evaluate thalamic arousal network functional connectivity in TLE and examine changes after epilepsy surgery. METHODS We examined 26 adult TLE patients and 26 matched control participants and used resting-state functional magnetic resonance imaging (fMRI) to measure functional connectivity between the thalamus (entire thalamus and 19 bilateral thalamic nuclei) and both neocortex and brainstem ascending reticular activating system (ARAS) nuclei. Postoperative imaging was completed for 19 patients > 1 yr after surgery and compared to preoperative baseline. RESULTS Before surgery, TLE patients demonstrated abnormal thalamo-occipital functional connectivity, losing the normal negative fMRI correlation between the intralaminar central lateral (CL) nucleus and medial occipital lobe seen in controls (P < .001, paired t-test). Patients also had abnormal connectivity between ARAS and CL, lower ipsilateral intrathalamic connectivity, and smaller ipsilateral thalamic volume compared to controls (P < .05 for each, paired t-tests). Abnormal brainstem-thalamic connectivity was associated with impaired visuospatial attention (? = −0.50, P = .02, Spearman's rho), while lower intrathalamic connectivity and volume were related to higher frequency of consciousness-sparing seizures (P < .02, Spearman's rho). After epilepsy surgery, patients with improved seizures showed partial recovery of thalamo-occipital and brainstem-thalamic connectivity, with values more closely resembling controls (P < .01 for each, ANOVA). CONCLUSION Overall, TLE patients demonstrate impaired connectivity in thalamic arousal networks that may be involved in visuospatial attention, but these disturbances may partially recover after successful epilepsy surgery. Thalamic arousal network dysfunction may contribute to morbidity in TLE.

scholarly journals Thalamic arousal network disturbances in temporal lobe epilepsy and improvement after surgery

2019 ◽  
Vol 90 (10) ◽  
pp. 1109-1116 ◽  
Author(s):  
Hernán F J González ◽  
Srijata Chakravorti ◽  
Sarah E Goodale ◽  
Kanupriya Gupta ◽  
Daniel O Claassen ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epilepsy Surgery ◽  
Occipital Lobe ◽  
Visuospatial Attention ◽  
Partial Recovery ◽  
Thalamic Nuclei ◽  
Spearman's Rho ◽  
Spearman’S Rho

ObjectiveThe effects of temporal lobe epilepsy (TLE) on subcortical arousal structures remain incompletely understood. Here, we evaluate thalamic arousal network functional connectivity in TLE and examine changes after epilepsy surgery.MethodsWe examined 26 adult patients with TLE and 26 matched control participants and used resting-state functional MRI (fMRI) to measure functional connectivity between the thalamus (entire thalamus and 19 bilateral thalamic nuclei) and both neocortex and brainstem ascending reticular activating system (ARAS) nuclei. Postoperative imaging was completed for 19 patients >1 year after surgery and compared with preoperative baseline.ResultsBefore surgery, patients with TLE demonstrated abnormal thalamo-occipital functional connectivity, losing the normal negative fMRI correlation between the intralaminar central lateral (CL) nucleus and medial occipital lobe seen in controls (p < 0.001, paired t-test). Patients also had abnormal connectivity between ARAS and CL, lower ipsilateral intrathalamic connectivity, and smaller ipsilateral thalamic volume compared with controls (p < 0.05 for each, paired t-tests). Abnormal brainstem–thalamic connectivity was associated with impaired visuospatial attention (ρ = −0.50, p = 0.02, Spearman’s rho) while lower intrathalamic connectivity and volume were related to higher frequency of consciousness-sparing seizures (p < 0.02, Spearman’s rho). After epilepsy surgery, patients with improved seizures showed partial recovery of thalamo-occipital and brainstem–thalamic connectivity, with values more closely resembling controls (p < 0.01 for each, analysis of variance).ConclusionsOverall, patients with TLE demonstrate impaired connectivity in thalamic arousal networks that may be involved in visuospatial attention, but these disturbances may partially recover after successful epilepsy surgery. Thalamic arousal network dysfunction may contribute to morbidity in TLE.

scholarly journals Resting state functional connectivity patterns associated with pharmacological treatment resistance in temporal lobe epilepsy

2018 ◽  
Author(s):  
Christina Pressl ◽  
Philip Brandner ◽  
Stefan Schaffelhofer ◽  
Karen Blackmon ◽  
Patricia Dugan ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Resting State ◽  
Treatment Resistance ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Treatment Resistant ◽  
Connectivity Patterns ◽  
Seizure Foci

AbstractThere are no functional imaging based biomarkers for pharmacological treatment response in temporal lobe epilepsy (TLE). In this study, we investigated whether there is an association between resting state functional brain connectivity (RsFC) and seizure control in TLE. We screened a large database containing resting state functional magnetic resonance imaging (Rs-fMRI) data from 286 epilepsy patients. Patient medical records were screened for seizure characterization, EEG reports for lateralization and location of seizure foci to establish uniformity of seizure localization within patient groups. Rs-fMRI data from patients with well-controlled left TLE, patients with treatment-resistant left TLE, and healthy controls were analyzed. Healthy controls and cTLE showed similar functional connectivity patterns, whereas trTLE exhibited a significant bilateral decrease in thalamo-hippocampal functional connectivity. This work is the first to demonstrate differences in neural network connectivity between well-controlled and treatment-resistant TLE. These differences are spatially highly focused and suggest sites for the etiology and possibly treatment of TLE. Altered thalamo-hippocampal RsFC thus is a potential new biomarker for TLE treatment resistance.SummaryResting State functional magnetic resonance imaging (Rs-fMRI), previously utilized to predict lateralization of seizure foci in temporal lobe epilepsy (TLE), is utilized to determine potential mechanisms and biomarkers for treatment-resistant and well-controlled unilateral TLE. We found significant differences in thalamo-hippocampal functional connectivity between treatment-resistant and well-controlled TLE patients. Differences in functional connectivity were focused to thalamo-hippocampal connections and more pronounced in the hemisphere ipsilateral to seizure foci. Aberrant functional connectivity patterns as measured by Rs-fMRI could thus serve as biomarkers for treatment response in TLE.

scholarly journals Hippocampal Functional Connectivity Patterns During Spatial Working Memory Differ in Right Versus Left Temporal Lobe Epilepsy

2013 ◽  
Vol 3 (4) ◽  
pp. 398-406 ◽  
Author(s):  
Gaëlle Doucet ◽  
Karol Osipowicz ◽  
Ashwini Sharan ◽  
Michael R. Sperling ◽  
Joseph I. Tracy
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Spatial Working Memory ◽  
Left Temporal Lobe ◽  
Connectivity Patterns

Functional connectivity networks are disrupted in left temporal lobe epilepsy

2006 ◽  
Vol 59 (2) ◽  
pp. 335-343 ◽  
Author(s):  
Anthony B. Waites ◽  
Regula S. Briellmann ◽  
Michael M. Saling ◽  
David F. Abbott ◽  
Graeme D. Jackson
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Left Temporal Lobe

scholarly journals Intrinsic Thalamic Network in Temporal Lobe Epilepsy With Hippocampal Sclerosis According to Surgical Outcomes

2021 ◽  
Vol 12 ◽  
Author(s):  
Kyoo Ho Cho ◽  
Ho-Joon Lee ◽  
Kyoung Heo ◽  
Sung Eun Kim ◽  
Dong Ah Lee ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Surgical Outcomes ◽  
Hippocampal Sclerosis ◽  
Three Dimensional ◽  
Thalamic Nuclei ◽  
Characteristic Path Length ◽  
Ipsilateral Hemisphere ◽  
Hippocampal Subfields ◽  
Significant Difference

Background: The aim of this study was to identify the differences of intrinsic amygdala, hippocampal, or thalamic networks according to surgical outcomes in temporal lobe epilepsy (TLE) patients with hippocampal sclerosis (HS).Methods: We enrolled 69 pathologically confirmed TLE patients with HS. All patients had pre-operative three-dimensional T1-weighted MRI using a 3.0 T scanner. We obtained the structural volumes of the amygdala nuclei, hippocampal subfields, and thalamic nuclei. Then, we investigated the intrinsic networks based on volumes of these structures using structural covariance and graph theoretical analysis.Results: Of the 69 TLE patients with HS, 21 patients (42.1%) had poor surgical outcomes, whereas 40 patients (57.9%) had good surgical outcomes. The volumes in the amygdala nuclei, hippocampal subfields, and thalamic nuclei were not different according to surgical outcome. In addition, the intrinsic amygdala and hippocampal networks were not different between the patients with poor and good surgical outcomes. However, there was a significant difference in the intrinsic thalamic network in the ipsilateral hemisphere between them. The eccentricity and small-worldness index were significantly increased, whereas the characteristic path length was decreased in the patients with poor surgical outcomes compared to those with good surgical outcomes.Conclusion: We successfully demonstrated significant differences in the intrinsic thalamic network in the ipsilateral hemisphere between TLE patients with HS with poor and good surgical outcomes. This result suggests that the pre-operative intrinsic thalamic network can be related with surgical outcomes in TLE patients with HS.

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