We used a randomization method motivated by deBettencourt et al. (2011) and threshold-free cluster enhancement (Smith and Nichols, 2009) to correct for multiple comparisons, by running a complete STV fMRI analysis after permuting the yτ=450ms values randomly within each class. 100 permutations were run for each subject. We carried these randomization results through to the group level and thresholded the statistical maps at per-voxel p = 0.005. For each cluster in the resulting null distribution, we summed the negative logarithm of the p-value over each voxel in the cluster. This provided a score for each cluster that, while highly dependent on cluster size, also accounted for some variation in the magnitude of the z-scores within the cluster. We determined a threshold based on the 99th percentile of these null-distribution cluster scores, or a p-value of 0.01.
