The time courses of factor loadings for the first five response-locked CSD factors extracted for each modality (both more than 90% explained variance after rotation) and corresponding factor score topographies of primary interest are given in Figure 8. Labels were chosen to indicate the peak latency of the factor loadings relative to response onset. In each modality, three CSD factors corresponded to the P3 source immediately preceding the response (auditory peak latency −150 ms; lateral-parietal sources paired with lateral-frontal sinks; 35.3% explained variance; visual −135 ms; mid-parietal and frontopolar sources; 25.1%), the FRN (auditory 45 ms; 4.7%; visual 40 ms; 4.4%; Fz sink maxima with centroparietal sources) and the LN sink (auditory 205 ms; 27.0%; visual 175 ms; 38.6%; occipital sinks with centrotemporal sources) following the response. In each modality, two earlier factors gathered variance evidently associated with stimulus-related activity.
