(A) For each maintenance interval and tempo, bursts are ordered according to their onset time. Below single trials, mean gamma amplitude is plotted as a function of time (trials starting on the left are shown; 131 sessions; interval duration was pseudo-randomly selected on each trial, but is grouped here for presentation; linewidth denotes s.e. across trials). (B) The temporal profile of gamma bursts is plotted for each stimulus transition (1st, 2nd, 3rd, and 4th, dotted lines in A), and for each interval duration (500, 750, and 1000 ms; top to bottom). The bursts have a stereotyped temporal shape and increase in amplitude after each consecutive transition. (C) Mean amplitude of gamma bursts plotted as a function of elapsed time for the three interval durations (500, 750, and 1000 ms; R2 = 0.86, exponential model).