ERPs topographies to target stimuli at peak latency are shown in Fig. 3. The auditory P300 was maximally positive over parietal scalp regions when observed at peak latency. The target stimulus effect displayed a midline focus of activity at centro-parietal area in the healthy control group, and the focus shifted to left hemisphere in depressed patients. In anxiety disorder patients, the foci were displayed in the right posterior scalp area. ERPs topographies to standard stimuli at the same time points are shown in Fig. 3 where all topographies showed obvious foci close to midline at posterior scalp area.
