title: Reducing Individual Variation for fMRI Studies in Children by Minimizing Template Related Errors.
abstract: Spatial normalization is an essential process for group comparisons in functional MRI studies. In practice, there is a risk of normalization errors particularly in studies involving children, seniors or diseased populations and in regions with high individual variation. One way to minimize normalization errors is to create a study-specific template based on a large sample size. However, studies with a large sample size are not always feasible, particularly for children studies. The performance of templates with a small sample size has not been evaluated in fMRI studies in children. In the current study, this issue was encountered in a working memory task with 29 children in two groups. We compared the performance of different templates: a study-specific template created by the experimental population, a Chinese children template and the widely used adult MNI template. We observed distinct differences in the right orbitofrontal region among the three templates in between-group comparisons. The study-specific template and the Chinese children template were more sensitive for the detection of between-group differences in the orbitofrontal cortex than the MNI template. Proper templates could effectively reduce individual variation. Further analysis revealed a correlation between the BOLD contrast size and the norm index of the affine transformation matrix, i.e., the SFN, which characterizes the difference between a template and a native image and differs significantly across subjects. Thereby, we proposed and tested another method to reduce individual variation that included the SFN as a covariate in group-wise statistics. This correction exhibits outstanding performance in enhancing detection power in group-level tests. A training effect of abacus-based mental calculation was also demonstrated, with significantly elevated activation in the right orbitofrontal region that correlated with behavioral response time across subjects in the trained group.
authors.affiliation: Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou, Zhejiang, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Weng
authors.affiliation: Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou, Zhejiang, P.R. China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Dong
authors.affiliation: Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang, P.R. China.
authors.forename: Hongjian
authors.initials: H
authors.lastname: He
authors.affiliation: Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou, Zhejiang, P.R. China.
authors.forename: Feiyan
authors.initials: F
authors.lastname: Chen
authors.affiliation: The First Hospital of Qiqihar, Qiqihar, Heilongjiang, P.R. China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Peng
mesh_terms: D000465:Algorithms; D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000502:physiology; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D059629:Signal-To-Noise Ratio