Figure 1

Signal processing of evoked potential responses in control and schizophrenic groups.(a) The EEG signals of behavioral performance at a task in which subjects had to identify and temporally order rapidly successive brief stimuli that in some trials. (b) Examples of evoked potential responses recorded in The Brain Atlas III Computer of the Biologic System Company. The system's versatility allows the user to record up to 4 sets of stimulus-evoked activity (including auditory ERP, visual ERP etc) and display and analyze the data in a variety of ways. The amplifier was used as follows: high filter, 30; low filter; 1.0; and gain, 20,000. (c)&(d) Averages were computed for the brain responses to target tones. Peak P300 amplitude, which accounts for individual variations in P300 latency, was measured as the most positive point from 250 to 400. Peak P400 amplitude, which accounts for individual variations in P400 latency, was measured as the most positive point from 400 to 500. The components of ERPs were identified as follows, P100, N100, P200, N200, P300, and P400. The figure 1c showed the averaged signals of evoked potentials from one normal control. The figure 1d showed the averaged signals of evoked potentials from one schizophrenic patient.