Figure 1.

Different classes of components detected by ICA decomposition of Stroop task fMRI data. (red, z ≥ 2.0; blue, z ≤ 2.0). Negative z values mean those voxels are activated opposite to the plotted time course. (a) Consistently task-related (CTR) component. (b) Transiently task-related (TTR) component. The dotted line shows the time course of the consistently task-related component for comparison. (c) Slowly varying, non-task-related component. The active region for this component was mostly localized to the ventricular system. The lower line shows the mean time course of the active voxels for this component. (d) Quasi-periodic component. This component was largely active in a single slice and had a dominant period of about 12 sec. The spatial distributions of such components were highly reproducible between trials. (e) Suspected abrupt head movement. Note abrupt change in time course, suggesting an abrupt head movement. (f) Component with a “ring-like” spatial structure is suggestive of a head movement.