Associations of resting-state fMRI functional connectivity with flow-BOLD coupling and regional vasculature.
There has been tremendous interest in applying functional magnetic resonance imaging-based resting-state functional connectivity (rs-fcMRI) measurements to the study of brain function. However, a lack of understanding of the physiological mechanisms of rs-fcMRI limits their ability to interpret rs-fcMRI findings. In this work, the authors examine the regional associations between rs-fcMRI estimates and dynamic coupling between the blood oxygenation level-dependent (BOLD) and cerebral blood flow (CBF), as well as resting macrovascular volume. Resting-state BOLD and CBF data were simultaneously acquired using a dual-echo pseudocontinuous arterial spin labeling (pCASL) technique, whereas macrovascular volume fraction was estimated using time-of-flight MR angiography. Functional connectivity within well-known functional networks—including the default mode, frontoparietal, and primary sensory-motor networks—was calculated using a conventional seed-based correlation approach. They found the functional connectivity strength to be significantly correlated with the regional increase in CBF-BOLD coupling strength and inversely proportional to macrovascular volume fraction. These relationships were consistently observed within all functional networks considered. Their findings suggest that highly connected networks observed using rs-fcMRI are not likely to be mediated by common vascular drainage linking distal cortical areas. Instead, high BOLD functional connectivity is more likely to reflect tighter neurovascular connections, attributable to neuronal pathways.
1 Rotman Research Institute at Baycrest Centre, University of Toronto , Toronto, Canada .
Sungho
S
Tak
Jonathan R
JR
Polimeni
Danny J J
DJ
Wang
Lirong
L
Yan
J Jean
JJ
Chen
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D055815:Young Adult
CBF-BOLD coupling; MR angiography; blood volume fraction; cerebral blood flow; resting-state BOLD; resting-state functional connectivity