Diffusion tensor tractography reveals disrupted structural connectivity in childhood absence epilepsy.
OBJECTIVE
The structural connection patterns of the human brain are the underlying bases for functional connectivity. Although abnormal functional connectivity has been uncovered in childhood absence epilepsy (CAE) in previous electroencephalography and functional magnetic resonance imaging studies, little is known regarding the structural connectivity in CAE. We hypothesized that the structural connectivity would be disrupted in response to the decreased brain function in CAE.


METHODS
Diffusion tensor imaging tractography was utilized to map the white matter (WM) structural network, composed of 90 cortical and sub-cortical regions, in 18 CAE and 18 age- and gender-matched healthy controls. Graph theoretical methods were applied to investigate the alterations in the topological and nodal properties of the networks in these patients.


RESULTS
Both the CAE and the controls showed small-world properties in their WM networks. However, the network connection strength, absolute clustering coefficient, and global/local efficiency were significantly decreased, but characteristic path length was significantly increased in the CAE compared with the controls. Significantly decreased WM connections, nodal properties, and impaired sub-networks were found in the sub-cortical structures, orbitofrontal area, and limbic cortex in the CAE. Moreover, network connection strength, local efficiency, and nodal features in some regions were significantly negatively correlated with the duration of epilepsy.


CONCLUSIONS
The present study demonstrated, for the first time, the disrupted topological organization of WM networks in CAE. The decreased connectivity and efficiency in the orbitofrontal and sub-cortical regions may serve as anatomical evidence to support the functional abnormalities related to the epileptic discharges observed in CAE. Moreover, the orbitofrontal sub-network may play a key role in CAE. These findings open up new avenues toward the understanding of absence epilepsy.
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Kaiqing
K
Xue
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Cheng
C
Luo
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Dan
D
Zhang
Department of Neurology, West China Hospital of Sichuan University, Chengdu, China.
Tianhua
T
Yang
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Jianfu
J
Li
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Diankun
D
Gong
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Long
L
Chen
Neuroimaging Department, Cuban Neuroscience Center, La Habana, Cuba.
Yasser Iturria
YI
Medina
Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
Jean
J
Gotman
Department of Neurology, West China Hospital of Sichuan University, Chengdu, China.
Dong
D
Zhou
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China. Electronic address: dyao@uestc.edu.cn.
Dezhong
D
Yao
D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004832:Epilepsy, Absence / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009415:Nerve Net / Q000473:pathology* / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology
Absence epilepsy; Diffusion tensor tractography; Graph theory; Structural connectivity