sink and source oscillations. The positive (red-purple) areas in the factor loadings plots (Fig. 7A) indicate the time-frequency range for a given factor, for example, spanning alpha to delta frequencies (spectral peak at 9 Hz) between 400 and 800 ms (temporal peak at 610 ms) for factor 610–9 (alpha ERD). The corresponding topographies reveal at which sites (scalp regions) factor scores are increased or decreased in relation to the grand mean (removed by factoring the covariance matrix), which translates into synchronization (ERS) or desynchronization (ERD). For the alpha ERD factor, the corresponding topographies for controls reveal little ‘alpha ERD’ (i.e., alpha to theta ERD between 400 and 800 ms) for nontargets across all sites (broad orange in Fig. 7B, row 2, column 1), prominent alpha ERD for targets over parietal, particular right parietal sites (blue areas in Fig. 7B, row 2, column 2), and less alpha ERD for novels over the same right parietal region (light blue areas in Fig. 7B, row 2, column 3). By comparison, alpha ERD was notably reduced in CHR patients (blue areas in Fig. 7B, row 1, columns 2 and 3). This pattern is entirely consistent which what can be seen from the original ERSP
