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Proceedings Paper

The impact of respiratory and cardiac effects on the phase and magnitude of resting-state fMRI signal
Author(s): Zikuan Chen; Vince Calhoun
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Paper Abstract

Functional magnetic resonance imaging (fMRI) relies on detecting small changes in signal during brain activities, in presence of various noise, including those caused by respiration and cardiac pulsation. In the resting state, there is no explicit task event except the baseline neuroactivities of awakeness and other unknowns. However, the resting state is accompanied with the cardiac and respiration pulsations, which are the explicit non-neuronal physiological sources of fMRI signals. By recording the respiration and cardiac waveforms in synchrony with the fMRI scanning, we may estimate the physiological modulation artifacts in the fMRI dataset by the temporal correlations between the waveforms and the fMRI signal. In this work, we demonstrate that the respiration and cardiac modulation effects on the magnitude and phase components of the complex fMRI signal, including temporal correlation and time latency. In particular, our results show that: 1) the fMRI phase is slightly more modulated by the physiological modulations than its magnitude counterpart; 2) the fMRI signal (both magnitude and phase) shows 1 to 2s latency to respiration stimulus, and 0 to 1s latency to cardiac stimulus. For physiological artifact removal, we compare the band-stop filtering method with the RETROICOR method and find the former can remove the physiological modulations in a stable and consistent manner in frequency domain (stopping the signature frequencies irrespective of asynchrony.

Paper Details

Date Published: 16 March 2011
PDF: 10 pages
Proc. SPIE 7965, Medical Imaging 2011: Biomedical Applications in Molecular, Structural, and Functional Imaging, 79652A (16 March 2011); doi: 10.1117/12.877321
Show Author Affiliations
Zikuan Chen, The Mind Research Network (United States)
Vince Calhoun, The Mind Research Network (United States)
Univ. of New Mexico (United States)


Published in SPIE Proceedings Vol. 7965:
Medical Imaging 2011: Biomedical Applications in Molecular, Structural, and Functional Imaging
John B. Weaver; Robert C. Molthen, Editor(s)

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