Paper Info
Title
Low-frequency fluctuations in the cardiac rate as a source of variance in the resting-state fMRI BOLD signal.
Abstract
Heart rate fluctuations occur in the low-frequency range (<0.1 Hz) probed in functional magnetic resonance imaging (fMRI) studies of resting-state functional connectivity and most fMRI block paradigms and may be related to low-frequency blood-oxygenation-level-dependent (BOLD) signal fluctuations. To investigate this hypothesis, temporal correlations between cardiac rate and resting-state fMRI signal timecourses were assessed at 3 T. Resting-state BOLD fMRI and accompanying physiological data were acquired and analyzed using cross-correlation and regression. Time-shifted cardiac rate timecourses were included as regressors in addition to established physiological regressors (RETROICOR (Glover, G.H., Li, T.Q., Ress, D., 2000. Image-based method for retrospective correction of physiological motion effects in fMRI: RETROICOR. Magn Reson Med 44, 162–167) and respiration volume per unit time (Birn, R.M., Diamond, J.B., Smith, M.A., Bandettini, P.A., 2006b. Separating respiratory-variation-related fluctuations from neuronal-activity-related fluctuations in fMRI. NeuroImage 31, 1536–1548). Significant correlations between the cardiac rate and BOLD signal timecourses were revealed, particularly negative correlations in gray matter at time shifts of 6–12 s and positive correlations at time shifts of 30–42 s (TR=6 s). Regressors consisting of cardiac rate timecourses shifted by delays of between 0 and 24 s explained an additional 1% of the BOLD signal variance on average over the whole brain across 9 subjects, a similar additional variance to that explained by respiration volume per unit time and RETROICOR regressors, even when used in combination with these other physiological regressors. This suggests that including such time-shifted cardiac rate regressors will be beneficial for explaining physiological noise variance and will thereby improve the statistical power in future task-based and resting-state fMRI studies.
Year
DOI
Venue
2007
10.1016/j.neuroimage.2007.07.037
NeuroImage
Keywords
Field
DocType
statistical power,low frequency,magnetic resonance imaging,resting state,rest,brain mapping,neuronal activity,plethysmography,cross correlation
Brain mapping,Neuroscience,Regression,Functional magnetic resonance imaging,Resting state fMRI,Psychology,Cognitive psychology,Heart rate,Statistics,Communication noise,Statistical power,Magnetic resonance imaging
Journal
Volume
Issue
ISSN
38
2
1053-8119
Citations 
PageRank 
References 
120
9.82
10
Authors
7
Search Limit
100120
Name
Order
Citations
PageRank
Karin Shmueli116512.88
Peter van Gelderen240335.74
Jacco A de Zwart333330.78
Silvina G. Horovitz421117.56
Masaki Fukunaga531927.13
J Martijn Jansma613511.05
Jeff H. Duyn783948.39