Estimates of localized power of non-stationary evoked potential time series were obtained using the S-transform, a time-frequency representation method developed by Stockwell et al. (Stockwell 2007; Stockwell et al. 1996). This method has been previously described and implemented in our laboratory to evaluate event-related signals in the time-frequency domain (Jones et al. 2006b; Kamarajan et al. 2006; Rangaswamy et al. 2007).
