Event-related electrophysiological data for the target stimulus from the visual oddball task and the auditory oddball task were analyzed. The amplitude envelope of the S-transform time-frequency region was averaged across single trials, per individual, to obtain estimates of event-related total power. Mean power was calculated for each electrode within time-frequency regions of interest that were defined by frequency band range and time intervals. The measures used in this analysis were the total power in the theta band (3.0-7.0 Hz) oscillation at the frontal (Fz), central (Cz), and parietal (Pz) midline electrodes extracted from the 300-700 ms. time window, which corresponds to the window of the P3 component in the event-related waveforms. The time window and frequency band were chosen to capture relevant data from both tasks at the cost of being overly wide in both frequency and time ranges for each task individually, and used for reporting previous theta ERO results from our laboratory (Kang et al., 2012). The electrodes were chosen because of previous use in studies from our own laboratory (Jones et al., 2006a,b) and other developmental studies (Stige et al., 2007; Nanova et al., 2008). Correlations between measures were estimated using a method described in section 2.3.2.
