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Abstract #1172

Resting-State Functional Connectivity Strength Depends on the Magnitude of Resting BOLD Fluctuations and Not Differences in CBF

Anna Leigh Rack-Gomer1,2, Joy Liau3, Thomas T. Liu1,2

1Bioengineering, UC San Diego, La Jolla, CA, United States; 2Center for Functional MRI, UC San Diego, La Jolla, CA, United States; 3School of Medicine , UC San Diego, La Jolla, CA, United States

Interpretation of inter-subject differences in resting-state functional connectivity is complicated by the BOLD signals dependence on vascular factors. We found functional connectivity strength to be correlated with resting-state fluctuation amplitude (RSFA) across healthy subjects, where RSFA has previously been shown to correspond to vascular reactivity within subjects. However, we did not find RSFA to be related to either the task-related cerebral blood flow (CBF) response or baseline CBF, suggesting that RSFA does not indicate vascular differences across subjects. Instead, RSFA may reflect true differences in spontaneous neural activity, which contribute to the normal variability found in resting-state functional connectivity.