The auditory response-related midfrontal sink (FRN) was significantly reduced in patients compared with controls (Figure 9C; cf. factor 45 in Table 4A). A group × condition interaction confirmed that an old-greater-than-new sink was present in controls, F(1, 38) = 10.5, p = .003, but not patients, F(1, 38) < 1.0, ns. The corresponding centroparietal source was also smaller in patients compared to controls but there were no condition effects at these sites. In contrast, the visual FRN revealed only an overall significant old/new effect (cf. factor 40 in Table 4B) stemming from greater sinks to old than new stimuli. The corresponding centroparietal source, which also revealed an overall old/new effect originating from old-greater-than-new sources (M ± SD, old = 0.78 ± 0.85, new = 0.54 ± 0.70), was again reduced in patients (cf. factor 40 in Figure 8D). Thus, a response-related midfrontal sink and centroparietal source activity was markedly reduced in patients, particularly for auditory stimuli.
