Baseline effects on resting-state functional connectivity

Correlations between spontaneous fluctuations in the blood oxygenation level dependent (BOLD) signal measured with functional MRI are finding increasing use as measures of functional connectivity in the brain, where differences can potentially predict cognitive performance and diagnose disease. However, the interpretation of resting-state functional connectivity changes can be complicated by the BOLD signal's dependence on both neural and vascular factors. For example, prior studies have shown that vasoactive agents that alter baseline cerebral blood flow (CBF), such as caffeine and carbon dioxide, can significantly alter the amplitude and dynamics of the task -related BOLD response. In addition, healthy inter-subject differences in the amplitude of the BOLD response to a visual task are highly correlated with baseline CBF. The purpose of this work was to determine whether resting- state BOLD measures were similarly modulated by inter- subject differences in baseline CBF or vasoactive substances. Since many diseases and pharmacological agents are known to alter the vasculature, this is an important potential confound to investigat