期刊
NEUROIMAGE
卷 40, 期 4, 页码 1567-1574出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.neuroimage.2007.09.040
关键词
fMRI; breath hold; CO2; CBF; hypercapnia; motor cortex; BOLD; scaling; Hemodynamic
资金
- NINDS NIH HHS [R01 NS039044, NS39044, NS049176-01A2, R01 NS049176] Funding Source: Medline
This study evaluated a calibration technique for scaling the fMRI-BOLD response during a simple motor task. A novel scaling parameter, resting state physiological fluctuation amplitude (RSFA), was tested using previously established scaling factors such as breath hold or 5% CO2. RSFA was hypothesized to contain vascular reactivity information present in the resting state fMRI signal. Subjects were scanned under various stimulus conditions: ( a) rest while breathing room air, (b) bilateral fingertapping, ( c) breath holding and (d) moderate hypercapnia ( breathing 5% CO2 + air). In all subjects who breathed 5% CO2, RSFA correlated highly with the BOLD response amplitude during 5% CO2 inhalation. Also, RSFA correlated highly with the amplitude of the BOLD response elicited by breath hold. RSFA was therefore used as a hemodynamic scaling factor to calibrate both the amplitude and spatial extent of the fMRI-BOLD response during the motor task ( fingertapping). Results revealed that amplitude scaling using RSFA was similar to that using breath hold or 5% CO2, where the spatial extent of activation diminished by 20-37% over all subjects. Spatial extent of activation changed significantly after scaling and only 30-40% of the activated area overlapped with the unscaled activation. RSFA-scaled task-induced fMRI-BOLD response in both amplitude and spatial extent was comparable to that obtained using breath hold or 5% CO2. We conclude that RSFA may be used to hemodynamically scale the fMRI-BOLD response and does not require the use of a hypercapnic challenge ( which may not be purely non-neural), which can be difficult to implement in special populations. (c) 2008 Published by Elsevier Inc.
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