Maneshi Mona, Vahdat Shahabeddin, Fahoum Firas, Grova Christophe, Gotman Jean
Montreal Neurological Institute and Hospital, McGill University , Montreal, QC , Canada.
Functional Neuroimaging Unit, Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal , Montreal, QC , Canada.
Front Neurol. 2014 Jul 14;5:127. doi: 10.3389/fneur.2014.00127. eCollection 2014.
We studied with functional magnetic resonance imaging (fMRI) differences in resting-state networks between patients with mesial temporal lobe epilepsy (MTLE) and healthy subjects. To avoid any a priori hypothesis, we use a data-driven analysis assessing differences between groups independently of structures involved. Shared and specific independent component analysis (SSICA) is an exploratory method based on independent component analysis, which performs between-group network comparison. It extracts and classifies components (networks) in those common between groups and those specific to one group. Resting fMRI data were collected from 10 healthy subjects and 10 MTLE patients. SSICA was applied multiple times with altered initializations and different numbers of specific components. This resulted in many components specific to patients and to controls. Spatial clustering identified the reliable resting-state networks among all specific components in each group. For each reliable specific network, power spectrum analysis was performed on reconstructed time-series to estimate connectivity in each group and differences between groups. Two reliable networks, corresponding to statistically significant clusters robustly detected with clustering were labeled as specific to MTLE and one as specific to the control group. The most reliable MTLE network included hippocampus and amygdala bilaterally. The other MTLE network included the postcentral gyri and temporal poles. The control-specific network included bilateral precuneus, anterior cingulate, thalamus, and parahippocampal gyrus. Results indicated that the two MTLE networks show increased connectivity in patients, whereas the control-specific network shows decreased connectivity in patients. Our findings complement results from seed-based connectivity analysis (1). The pattern of changes in connectivity between mesial temporal lobe structures and other areas may help us understand the cognitive impairments often reported in patients with MTLE.
我们使用功能磁共振成像(fMRI)研究了内侧颞叶癫痫(MTLE)患者与健康受试者静息态网络的差异。为避免任何先验假设,我们采用数据驱动分析,独立于所涉及的结构评估组间差异。共享和特定独立成分分析(SSICA)是一种基于独立成分分析的探索性方法,用于进行组间网络比较。它提取并分类组间共有的成分(网络)以及特定于一组的成分。从10名健康受试者和10名MTLE患者收集了静息态fMRI数据。对SSICA进行了多次不同初始化和不同数量特定成分的应用。这产生了许多特定于患者和对照组的成分。空间聚类在每组的所有特定成分中识别出可靠的静息态网络。对于每个可靠的特定网络,对重建的时间序列进行功率谱分析,以估计每组的连通性以及组间差异。两个与通过聚类稳健检测到的具有统计学意义的簇相对应的可靠网络被标记为特定于MTLE,另一个为特定于对照组。最可靠的MTLE网络双侧包括海马体和杏仁核。另一个MTLE网络包括中央后回和颞极。对照组特定网络包括双侧楔前叶、前扣带回、丘脑和海马旁回。结果表明,两个MTLE网络在患者中显示出连通性增加,而对照组特定网络在患者中显示出连通性降低。我们的发现补充了基于种子点的连通性分析的结果(1)。内侧颞叶结构与其他区域之间连通性变化的模式可能有助于我们理解MTLE患者中经常报告的认知障碍。