ERSP and ITC measures were examined with EEGLab version 11.0.4.3b, MATLab version R2011a, with statistical analyses performed in R1.15.1. Our data processing pipeline involved computing ERSP and ITC values in EEGLab, using algorithms for implementing a time × frequency spectrogram (Delorme & Makeig, 2004). Specifically, we relied on the EEGLab function “newtimef” to calculate the average ERSP and ITC across the medial frontal channel cluster. ERSP and ITC calculations relied on both fast Fourier Transform (at the lowest frequency) and wavelet decomposition (at the highest frequency). Using the standard setting with EEGLab (cycles were set as [3,0.5]), cycles increase linearly with frequency from 0 for FFT (same window width at all frequencies) to 1 for wavelet (same number of cycles at all frequencies). Specifically, the software uses 3 cycles at lowest frequency to 11.25 cycles at highest. The time-frequency decomposition yields a time × frequency transform with a complex number for every time point, frequency, and trial. ERSP and ITC data were obtained at 53 linear-spaced frequencies, 4.0-30.0 Hz, and 290 linear-spaced time points from -582 to 578 ms (i.e., 836 ms sliding window) relative to the stimulus onset1.
