中国科学院行为科学重点实验室知识库

As researchers increase their efforts to characterize variations in the functional connectome across studies and individuals, concerns about the many sources of nuisance variation present and their impact on resting state fMRI (R-fMRI) measures continue to grow. Although substantial within-site variation can exist efforts to aggregate data across multiple sites such as the 1000 Functional Connectomes Project (FCP) and International Neuroimaging Data-sharing Initiative (INDI) datasets amplify these concerns. The present work draws upon standardization approaches commonly used in the microarray gene expression literature, and to a lesser extent recent imaging studies, and compares them with respect to their impact on relationships between common R-fMRI measures and nuisance variables (e.g., imaging site, motion), as well as phenotypic variables of interest (age, sex). Standardization approaches differed with regard to whether they were applied post-hoc vs. during pre-processing, and at the individual vs. group level; additionally they varied in whether they addressed additive effects vs. additive + multiplicative effects, and were parametric vs. non-parametric. While all standardization approaches were effective at reducing undesirable relationships with nuisance variables, post-hoc approaches were generally more effective than global signal regression (GSR). Across approaches, correction for additive effects (global mean) appeared to be more important than for multiplicative effects (global SD) for all R-fMRI measures, with the exception of amplitude of low frequency fluctuations (ALFF). Group-level post-hoc standardizations for mean-centering and variance-standardization were found to be advantageous in their ability to avoid the introduction of artifactual relationships with standardization parameters; though results between individual and group-level post-hoc approaches were highly similar overall. While post-hoc standardization procedures drastically increased test-retest (TRT) reliability for ALFF, modest reductions were observed for other measures after post-hoc standardizations a phenomena likely attributable to the separation of voxel-wise from global differences among subjects (global mean and SD demonstrated moderate TRT reliability for these measures). Finally, the present work calls into question previous observations of increased anatomical specificity for GSR over mean centering, and draws attention to the near equivalence of global and gray matter signal regression. (C) 2013 Elsevier Inc. All rights reserved.

This work was supported by grants from the National Institute of Mental Health (BRAINS R01MH094639 to M.P.M.; R03MH096321 to M.P.M), the Stavros Niarchos Foundation (M. P. M), the Brain and Behavior Research Foundation (R.C.C.), the National Natural Science Foundation of China (81171409, 81220108014 to X.N.Z.), and the Startup Foundation for Distinguished Research Professor of the Institute of Psychology (Y0CX492S03 to X.N.Z.), the Key Research Program (KSZD-EW-TZ-002 to X.N.Z) of the Chinese Academy of Sciences. Additional support provided by a gift from Joseph P. Healey to the Child Mind Institute (M.P.M.). Thanks to Adriana Di Martino and F. Xavier Castellanos for helpful comments on the manuscript during preparation.