Figure 2

Ten minutes of spontaneous activity from P1 ferret retina recorded using a MEA. The name of the data file is given at the top of the plot. A: the estimated position of each unit is plotted. Each spike train is given a unique number; overlapping numbers indicate that more than one unit was assigned the same position. B: the firing rate estimated in one second bins, averaged across the entire array. Periodic elevations in firing rate, followed by long periods of relative silence, are characteristic of retinal waves. C: the raster showing the spike times of all units (starting with unit one at the bottom). D: the correlation index plot [29], described in detail in Figure 3 (Dynamic).