Fig. 3.

MEG responses to the emergence and violation of a regular pattern. (A) Group-RMS (RMS of individual RMSs; 13 subjects) of brain responses to RAND-REG (Upper) and REG-RAND (Lower) conditions, along with their respective no-change controls. The figures show the entire stimulus epoch, from stimulus onset (t = 0) to offset (t = 4,500 ms). Shaded areas around the curves represent twice the SEM, computed with bootstrap resampling (60; 1,000 iterations; with replacement). Respective transition times are marked by a dotted black line. Intervals where a repeated measures bootstrap procedure indicated significant differences between conditions are marked with a black line, underneath the brain response. The high pass-filtered responses are also plotted underneath the main curve. (B) Single trial data from a representative subject for RAND-REG (Upper) and REG-RAND (Lower). In each panel, the top plot displays the RMS response (in orange or blue, respectively) computed across averaged data from the 40 selected channels for that subject (in gray). Raster plots (Lower) show the single trial data for each condition. Data for each trial were temporally smoothed using a moving average over 10 adjacent samples (16.6 ms) and normalized between 0 and 1 to facilitate visualization. To quantify the temporal jitter in transition responses, the transition time within each trial is estimated by cross-correlating the single trial RMS time course with an ascending (for RAND-REG) or descending (REG-RAND) Heaviside-step function. The lags that gave the maximum correlation value for each trial are plotted in the histograms.