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Neural Plasticity
Volume 2016, Article ID 8583420, 11 pages
http://dx.doi.org/10.1155/2016/8583420
Research Article

Distinctive Structural and Effective Connectivity Changes of Semantic Cognition Network across Left and Right Mesial Temporal Lobe Epilepsy Patients

1Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
2Departments of Psychology and Linguistics, Xidian University, Xi’an 710126, China
3Neuroimaging Laboratory, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen 518060, China
4Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
5Department of Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
6Department of Biomedical Engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
7Center of Stroke, Beijing Institute for Brain Disorder, Beijing 100069, China
8Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing 100053, China
9Center of Epilepsy, Beijing Institute for Brain Disorder, Beijing 100069, China

Received 10 July 2016; Accepted 20 September 2016

Academic Editor: Kevin K. W. Wang

Copyright © 2016 Xiaotong Fan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Occurrence of language impairment in mesial temporal lobe epilepsy (mTLE) patients is common and left mTLE patients always exhibit a primary problem with access to names. To explore different neuropsychological profiles between left and right mTLE patients, the study investigated both structural and effective functional connectivity changes within the semantic cognition network between these two groups and those from normal controls. We found that gray matter atrophy of left mTLE patients was more severe than that of right mTLE patients in the whole brain and especially within the semantic cognition network in their contralateral hemisphere. It suggested that seizure attacks were rather targeted than random for patients with hippocampal sclerosis (HS) in the dominant hemisphere. Functional connectivity analysis during resting state fMRI revealed that subregions of the anterior temporal lobe (ATL) in the left HS patients were no longer effectively connected. Further, we found that, unlike in right HS patients, increased causal linking between ipsilateral regions in the left HS epilepsy patients cannot make up for their decreased contralateral interaction. It suggested that weakened contralateral connection and disrupted effective interaction between subregions of the unitary, transmodal hub of the ATL may be the primary cause of anomia in the left HS patients.