The effects of respiratory CO2 fluctuations in the resting-state BOLD signal differ between eyes open and eyes closed
Journal
Magnetic Resonance Imaging
Journal Volume
31
Journal Issue
3
Pages
336-345
Date Issued
2013
Author(s)
Abstract
Resting fluctuations in arterial CO2 (a cerebral vasodilator) are believed to be an important source of low-frequency blood oxygenation level dependent (BOLD) signal fluctuations. In this study we focus on the two commonly used resting-states in functional magnetic resonance imaging experiments, eyes open and eyes closed, and quantify the degree to which measured spontaneous fluctuations in the partial pressure of end-tidal CO2 (Petco2) relate to BOLD signal time series. A significantly longer latency of BOLD signal changes following Petco2 fluctuations was found in the eyes closed condition compared to with eyes open, which may reveal different intrinsic vascular response delays in CO2 reactivity or an alteration in the net BOLD signal arising from Petco2 fluctuations and altered neural activity with eyes closed. By allowing a spatially varying time delay for the compensation of this temporal difference, a more spatially consistent CO2 correlation map can be obtained. Finally, Granger-causality analysis demonstrated a "causal" relationship between Petco2 and BOLD. The identified dominant Petco2→BOLD directional coupling supports the notion that Petco2 fluctuations are indeed a cause of resting BOLD variance in the majority of subjects. ? 2013 Elsevier Inc.
Subjects
carbon dioxide
adult
article
blood vessel reactivity
BOLD signal
eye movement
female
functional assessment
functional magnetic resonance imaging
functional neuroimaging
human
human experiment
image analysis
image processing
latent period
male
normal human
nuclear magnetic resonance scanner
priority journal
signal transduction
brain
brain circulation
comparative study
lung gas exchange
metabolism
methodology
nerve cell network
nuclear magnetic resonance imaging
physiology
reproducibility
rest
sensitivity and specificity
Adult
Brain
Carbon Dioxide
Cerebrovascular Circulation
Female
Functional Neuroimaging
Humans
Magnetic Resonance Imaging
Male
Nerve Net
Pulmonary Gas Exchange
Reproducibility of Results
Rest
Sensitivity and Specificity
Type
journal article