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Abstract #3703

The Effect of Hypercapnia on Resting State FMRI

Jinsoo Uh1, Feng Xu1, Uma Yezhuvath1, Yamei Cheng1, Hong Gu2, Yihong Yang2, Hanzhang Lu1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Neuroimaging Research Branch, National Institute on Drug Abuse, National Institute of Health, Baltimore, MD, USA

Hypercapnia (HC) challenge provides an excellent model condition for studying brain activity. We investigated the effect of HC on Resting State Network (RSN) and compared it with that on visual-evoked BOLD signals. We found that RSN shows a reduction in both cluster size and signal amplitude due to HC challenge. We also found a similar reduction of visual fMRI signal in the same subjects. This result indicates that vascular effects such as basal CBF and venous oxygenation contribute to the reduction of RSN as they do to visual fMRI signal. Thus, caution should be used in interpreting BOLD RSN changes.