Figure 2A compares the grand mean CSD waveforms of patients and controls at selected left-hemispheric inferior lateral-parietal sites where N1 sink was prominent for words (P7, P9), and at homologous right-hemispheric sites for faces (P8, P10) for both RM and WM paradigms. These corrected (i.e., peak-aligned) grand mean CSDs were highly comparable to those not adjusted for N1 sink peak latency (supplementary Figure S1 depicts these CSDs along with their nose-referenced ERP counterparts). A distinct component structure, consisting of P1 source (approximate peak latency 85 ms), N1 sink (145 ms), and P2 source (240 ms for faces), was observed for the three groups in both paradigms. In all conditions, however, auditory hallucinators revealed marked reductions of N1 sink compared to nonhallucinators and controls who had almost identical N1 sink amplitudes. In contrast, no obvious group differences were seen for P1 source amplitude. Parallel ANOVAs computed for P1 source factors (RM vs. WM, 98 vs. 105 ms peak latency, 6.1% vs. 5.2% explained variance) yielded no significant effects involving group (all F ≤1.88, all p ≥ .16).
