Figure 7.

Design matrix for condition-rich ungrouped-events fMRI design. Both panels illustrate the design matrix used for the 96-image experiment, an example of a condition-rich ungrouped-events design. The top panel shows the hemodynamic predictor time courses for the experimental events occurring in the first couple of minutes of the first run. Note that events occur at 4-s trial-onset asynchrony, yielding overlapping but dissociable hemodynamic responses and a reasonable frequency of stimulus presentation. (Each of the 96 conditions occurs exactly once in each run. The condition sequence is independently randomized for each run.) The bottom panel shows the complete design matrix with predictor amplitude color coded (see colorbar on the right). In addition to the 96 predictors for the experimental conditions, the design matrix also includes components modeling slow artefactual trends and residual head-motion artefacts (after rigid-body head-motion correction), and a confound-mean predictor for each run.