Abstract
Head motion is one of major concerns in current resting-state functional MRI studies. Image realignment including motion estimation and spatial resampling is often applied to achieve rigid-body motion correction. While the accurate estimation of motion parameters has been addressed in most studies, spatial resampling could also produce spurious variance, and lead to unexpected errors on the amplitude of BOLD signal. In this study, two simulation experiments were designed to characterize these variance related with spatial resampling. The fluctuation amplitude of spurious variance was first investigated using a set of simulated images with estimated motion parameters from a real dataset, and regions more likely to be affected by spatial resampling were found around the peripheral regions of the cortex. The other simulation was designed with three typical types of motion parameters to represent different extents of motion. It was found that areas with significant correlation between spurious variance and head motion scattered all over the brain and varied greatly from one motion type to another. In the last part of this study, four popular motion regression approaches were applied respectively and their performance in reducing spurious variance was compared. Among them, Friston 24 and Voxel-specific 12 model (Friston et al., 1996), were found to have the best outcomes. By separating related effects during fMRI analysis, this study provides a better understanding of the characteristics of spatial resampling and the interpretation of motion-BOLD relationship.
Highlights
Functional magnetic resonance imaging is a technique that utilizes the blood oxygen level dependent (BOLD) effect to indirectly detect the neuronal activity. fMRI studies have shown explosive growth and a wide range of clinical applications (Greicius, 2008; Lee et al, 2013)
The result of one sample t-test revealed that the regions more likely to be affected by volumetric registration appeared around the peripheral regions of the cortex, including most areas of the frontal cortex, the middle, and superior temporal gyrus, middle occipital gyrus and a tiny area of the inferior parietal lobule (Figure 3, n = 44, per-voxel threshold of p = 0.01 and a FWE-corrected threshold of p = 0.05 via the bug-fixed 3dClustSim, t >2.416)
This study aimed to evaluate the influence of spatial resampling and the merits of motion regression approaches with a simulation metric
Summary
Functional magnetic resonance imaging (fMRI) is a technique that utilizes the blood oxygen level dependent (BOLD) effect to indirectly detect the neuronal activity. fMRI studies have shown explosive growth and a wide range of clinical applications (Greicius, 2008; Lee et al, 2013). Functional magnetic resonance imaging (fMRI) is a technique that utilizes the blood oxygen level dependent (BOLD) effect to indirectly detect the neuronal activity. Since neuronal activities can cause BOLD signal changes of a few percent at best locally in the brain, Abbreviations: fMRI, functional magnetic resonance imaging; BOLD, blood oxygen level dependent; WM, white matter; CSF, cerebral spinal fluid; ALFF, amplitude of low frequency fluctuation; MNI, Montreal Neurological Institute; FWHM, full-width half-maximum; SD, the standard deviation; SV, spurious variance; TDvox, the voxel-wise total displacement; SDmean, the mean of SD values within the brain. Foam pad, bite bars or facial masks have been used to fix the head position and alleviate the influence of head motion directly These restraint devices can make the subject uncomfortable and distracted more likely to trigger undesired neuronal activities (Lueken et al, 2012). Prospective motion correction maintains a relative invariable position between the imaging volume and the moving brain by tracking head motion and continuously updating the imaging pulse sequence (Maclaren et al, 2013), but the special requirements for sequence design reduce its effectiveness in routine experiments
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
