ERO and phase-locking index (PLI) analyses were accomplished from the same datasets that were used to generate the cortical ERP data reported in a previous publication (Ehlers et al., 1999). Data from each trial generated by the stimuli were processed by a time-frequency analysis algorithm, which utilizes the S-transform (Stockwell et al., 1996), a generalization of the Gabor transform (Gabor, 1946), defined as: S[jT,nNT]=∑m=0N−1H[m+nNT]e−2π2m2n2ei2πmjNn≠0
