White matter network disorder in mesial temporal epilepsy: An fMRI study
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Updated: Nov 16, 2025
Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy
Published on: August 5, 2014
Wei Cui1, Kun Shang2, Bensheng Qiu3
1Center for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China; Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
Abstract:
Mesial temporal lobe epilepsy (mTLE) has been considered a network disorder disease in which brain regions extending beyond the epileptogenic zones are always affected. However, abnormalities in white matter (WM) functional networks and their associations with widespread network dysfunction are still being identified in mTLE. Accordingly, we investigated the altered functional activities in WM networks in mTLE using fMRI, which has recently been used to probe WM function. We collected resting-state fMRI data from 39 unilateral mTLE patients with hippocampal sclerosis and 29 healthy controls. Eleven WM networks were clustered according to temporal correlation profile. The functional connectivity (FC) of the WM networks were evaluated and compared between the two groups. Furthermore, we assessed the capacity of WM FC for seizure lateralization. According to our analysis, mTLE led to decreased FC within deep WM networks. In addition, the cortical regions involved in seizure propagation and several brain regions displaying interhemispheric disruption showed enhanced functional coupling with deep WM networks. FCs between the ipsilateral deep WM networks and the insula, temporal lobe, and supramarginal gyrus demonstrated positive correlation with seizure frequency. Moreover, the seizure onset zones of 33 patients out of 39 patients could be correctly lateralized. Our findings reveal functional disruptions in WM networks extending to extratemporal regions, supporting the network disorder hypothesis and suggesting that deep WM networks are key network nodes associated with massive dysfunction in mTLE. Moreover, the FC of the WM represents a potentially useful functional imaging measure for the diagnosis of mTLE.
Insights
Mesial temporal lobe epilepsy (mTLE) disrupts white matter (WM) functional networks, showing decreased connectivity in deep WM networks. This functional connectivity aids in diagnosing mTLE and lateralizing seizures.
Area of Science:
- Neuroscience
- Epilepsy Research
- Functional Neuroimaging
Background:
- Mesial temporal lobe epilepsy (mTLE) is increasingly recognized as a network disorder.
- While cortical abnormalities are known, white matter (WM) network dysfunction in mTLE requires further investigation.
- Functional magnetic resonance imaging (fMRI) offers a novel approach to study WM functional activity.
Purpose of the Study:
- To investigate altered functional activities within WM networks in mTLE patients using fMRI.
- To explore the association between WM functional connectivity (FC) and widespread network dysfunction.
- To assess the utility of WM FC for seizure lateralization in mTLE.
Main Methods:
- Resting-state fMRI data were acquired from 39 mTLE patients and 29 healthy controls.
- Eleven WM networks were identified and their functional connectivity (FC) was analyzed.
- FC was compared between groups, and correlations with seizure frequency and lateralization were examined.
Main Results:
- mTLE patients exhibited decreased FC within deep WM networks compared to controls.
- Enhanced functional coupling was observed between deep WM networks and cortical regions involved in seizure propagation and interhemispheric disruption.
- FC between ipsilateral deep WM networks and specific cortical regions correlated positively with seizure frequency.
- Seizure onset zones were successfully lateralized in 33 out of 39 patients using WM FC.
Conclusions:
- Functional disruptions in WM networks extend beyond epileptogenic zones in mTLE, supporting the network disorder hypothesis.
- Deep WM networks are critical nodes implicated in the widespread network dysfunction observed in mTLE.
- WM functional connectivity is a promising imaging biomarker for mTLE diagnosis and seizure lateralization.
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