Figure 1.

(A) Grand average ERP responses in the placebo condition to the sixth tone of stimulus trains (“standard tone”; black line) and the first tone of stimulus trains (“deviant” tone; dashed line) across frontal and central electrodes. (B) Spatiotemporal SPM representation of the MMN response in the placebo condition: Comparison between the first and the sixth tone presentations, the “deviant” and the “standard”, respectively. SPM analysis was performed across all 64 channels and across the entire epoch [−100 400]. The SPM results show a significant negative difference over bilateral frontal electrodes in the range of 160 and 180 ms, peaking at 177 ms.