Comparison of two exploratory data analysis methods for fMRI: fuzzy clustering vs. principal component analysis

Exploratory data-driven methods such as Fuzzy clustering analysis (FCA) and Principal component analysis (PCA) may be considered as hypothesis-generat ing procedures that are complementary to the hypothesis-led statistical inf erential methods in functional magnetic resonance imaging (fMRI). Here, a c omparison between FCA and PCA is presented in a systematic fMRI study, with MR data acquired under the null condition, i.e., no activation, with diffe rent noise contributions and simulated, varying "activation." The contrast- to-noise (CNR) ratio ranged between 1-10. We found that if fMRI data are co rrupted by scanner noise only, FCA and PCA show comparable performance. In the presence of other sources of signal variation (e.g., physiological nois e), FCA outperforms PCA in the entire CNR range of interest in fMRI, partic ularly for low CNR values. The comparison method that we introduced may be used to assess other exploratory approaches such as independent component a nalysis or neural network-based techniques. Crown Copyright (C) 2000. Publi shed by Elsevier Science Inc.