title: Specific resting-state brain networks in mesial temporal lobe epilepsy.
abstract: 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.
authors: Montreal Neurological Institute and Hospital, McGill University , Montreal, QC , Canada.
authors: Mona
authors: M
authors: Maneshi
authors: Functional Neuroimaging Unit, Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal , Montreal, QC , Canada.
authors: Shahabeddin
authors: S
authors: Vahdat
authors: Montreal Neurological Institute and Hospital, McGill University , Montreal, QC , Canada.
authors: Firas
authors: F
authors: Fahoum
authors: Montreal Neurological Institute and Hospital, McGill University , Montreal, QC , Canada ; Multimodal Functional Imaging Laboratory, Department of Biomedical Engineering, McGill University , Montreal, QC , Canada.
authors: Christophe
authors: C
authors: Grova
authors: Montreal Neurological Institute and Hospital, McGill University , Montreal, QC , Canada.
authors: Jean
authors: J
authors: Gotman
keywords: brain networks; functional connectivity; independent component analysis; resting-state fMRI; temporal lobe epilepsy