Model order selection in group independent component analysis (ICA) has a significant effect on the obtained components. This study investigated the reproducible brain regions of abnormal default-mode network (DMN) functional connectivity related with cocaine addiction through different model order settings in group ICA. Resting-state fMRI data from 24 cocaine addicts and 24 healthy controls were temporally concatenated and processed by group ICA using model orders of 10, 20, 30, 40, and 50, respectively. For each model order, the group ICA approach was repeated 100 times using the ICASSO toolbox and after clustering the obtained components, centrotype-based anterior and posterior DMN components were selected for further analysis. Individual DMN components were obtained through back-reconstruction and converted to z-score maps. A whole brain mixed effects factorial ANOVA was performed to explore the differences in resting-state DMN functional connectivity between cocaine addicts and healthy controls. The hippocampus, which showed decreased functional connectivity in cocaine addicts for all the tested model orders, might be considered as a reproducible abnormal region in DMN associated with cocaine addiction. This finding suggests that using group ICA to examine the functional connectivity of the hippocampus in the resting-state DMN may provide an additional insight potentially relevant for cocaine-related diagnoses and treatments.
Bibliographical noteFunding Information:
This research was supported in part by the World Class University (WCU) Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science, and Technology , under Grant R31-10008 ; and in part by the NRF Grant 2012-005741 funded by the Ministry of Education, Science, and Technology . We also would like to thank Clare Kelly with Grant R03DA024775 from the National Institute on Drug Abuse for collecting and sharing the dataset.
- Cocaine addiction
- Default-mode network
- Functional connectivity
- Group ICA
- Model order
ASJC Scopus subject areas