Fig. 4.

Characteristics of the cortical population response to whisker deflection. A, The composite PSTH was formed by summing 434 individual PSTHs across all responding electrodes for all stimuli in all rats. B, Composite PSTHs for on-center electrodes (solid line) and off-center electrodes (dotted line) are shown separately. The sum of these is the total PSTH of A.C, Histogram of total evoked spikes (across the entire array) per stimulus trial is plotted for the same data considered inA. D, For each stimulus site the number of responding electrodes was counted; the distribution of electrode counts is shown by using the bottom scale. Thetop scale indicates the corresponding cortical area, assuming each electrode to be representative of 0.16 mm².