Strength of responses to stimulation during the development of dense cultures. A Increase in ASDR during the first 50 ms post-stimulus, averaged over all 50 presentations and 59 electrodes. Each dot represents a set of stimuli delivered to one culture on a given day, colored by plating batch and horizontally jittered for visual clarity. The line is the interpolated average across all cultures, using a Gaussian window with a half-width of 1 day. B Fraction of stimuli that evoked a burst.