Analysis of Residual Dependencies of Independent Components Extracted from fMRI Data

Figure 1

IC maps extracted from simulated datasets. The IC maps (in red-yellow) are transformed in -scores maps, thresholded, and superimposed on the anatomy. Only the ICs related to activated ROI #1 and ROI #2 are shown. (a) Noise level and time delay is 2.5 s; model order . (b) Model order , noise level , and time delay is 1.25 s. In this case, ICA could not separate the two activated regions in different components. Specifically, the activated regions are described by four IC maps. Each map described both ROI #1 and ROI #2. (c) The IC map number 4 estimated in the case of noise level and time delay of 1.25 seconds with model order = 15. To better show the intensity map distribution this IC is shown twice using two different thresholds applied to the -score statistics: the spatial distribution of the map is flatter with respect to the components related to the ROIs.

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