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Computational Intelligence and Neuroscience
Volume 2016, Article ID 1068434, 22 pages
http://dx.doi.org/10.1155/2016/1068434
Research Article

Evaluation of Second-Level Inference in fMRI Analysis

Department of Data Analysis, Ghent University, H. Dunantlaan 1, 9000 Ghent, Belgium

Received 9 July 2015; Revised 21 August 2015; Accepted 4 October 2015

Academic Editor: Pierre L. Bellec

Copyright © 2016 Sanne P. Roels et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigate the impact of decisions in the second-level (i.e., over subjects) inferential process in functional magnetic resonance imaging on (1) the balance between false positives and false negatives and on (2) the data-analytical stability, both proxies for the reproducibility of results. Second-level analysis based on a mass univariate approach typically consists of 3 phases. First, one proceeds via a general linear model for a test image that consists of pooled information from different subjects. We evaluate models that take into account first-level (within-subjects) variability and models that do not take into account this variability. Second, one proceeds via inference based on parametrical assumptions or via permutation-based inference. Third, we evaluate 3 commonly used procedures to address the multiple testing problem: familywise error rate correction, False Discovery Rate (FDR) correction, and a two-step procedure with minimal cluster size. Based on a simulation study and real data we find that the two-step procedure with minimal cluster size results in most stable results, followed by the familywise error rate correction. The FDR results in most variable results, for both permutation-based inference and parametrical inference. Modeling the subject-specific variability yields a better balance between false positives and false negatives when using parametric inference.