Functional connectivity of cortical resting-state networks is differentially affected by rest conditions

Optimal conditions for resting-state functional magnetic resonance imaging (rs-fMRI) are still highly debated. Here, we comprehensively assessed the effects of various rest conditions on all cortical resting-state networks (RSNs) defined by an established atlas. Twenty-two healthy college students (22 +/- 4 years old, 12 females) were scanned on a GE 3T MRI scanner. Rs-fMRI datasets were collected under four different conditions for each subject: (1) eyes open in dim light (Eyes-Open), (2) eyes closed and awake (Eyes-Closed), (3) eyes closed while remembering four numbers through the scan session (Eyes-Closed-Number) and (4) asked to watch a movie (Movie). We completed a thorough examination of the 17 functional RSNs defined by Yeo and colleagues. Importantly, the movie led to changes in global connectivity and should be avoided as a rest condition. Conversely, there were no significant connectivity differences between conditions within the frontoparietal control and limbic networks and the following subnetworks as defined by Yeo et al.: default -B, dorsal-attention -B and salience/ventral-attention-B. These were not even significant when compared to the highly stimulative Movie condition. A significant difference was not found between Eyes-Closed and Eyes-Closed-Number condi-tions in whole-brain, within-network and between-network comparisons. When considering other rest condi-tions, however, we observed connectivity changes in some subnetworks, including those of the default-mode network. Overall, we found conditions with more external stimulation led to more changes in functional con-nectivity during rs-fMRI. In conclusion, the comprehensive results of our study can aid in choosing rest condi-tions for the study of overall and specific functional networks.

Automated summary

The study compared the effects of different rest conditions on cortical resting-state networks and found that watching a movie led to global connectivity changes and should be avoided as a rest condition. Connectivity changes were observed in some subnetworks with more external stimulation leading to greater changes in functional connectivity during rs-fMRI.