Fig. 7. Burst profile representations, averaged over 15 experiments (chosen from those in which the PPN did not include activity of an early unit). The mean cumulative amplitude burst profiles were calculated for each recording. (Ai) Mean cumulative amplitude burst profiles averaged over all preparations. (Aii) Magnification of the burst time window. (Bi, Bii) The first derivative of the above, normalized to yield burst energy densities. Again, the left and right columns differ only by the horizontal (time) domain. Note the strong pre-burst PPN inhibition and the post-burst inhibition in all three nerves. (C) Time-lag diagram calculated by linear extrapolation of burst onset and termination times in cumulative amplitude traces from each of the recordings. The diagram summarizes burst temporal progression in the three nerves (means ± S.D.). N=15, 14 and 5 for FC, MPN and PPN, respectively.