Figure 1.

Developmental changes in firing pattern. A, Example of bursting firing pattern of a principal neuron from the MNTB of a P5 rat during an in vivo juxtacellular recording. Bottom, Complex waveforms at higher time resolution, consisting of a prespike, and followed by an eEPSP and the postsynaptic action potential (eAP). The bottom panel shows the interevent interval histogram. Preferred intervals cluster around 10 ms, a few hundred milliseconds, and 10 s. B, As in A, except that the age of the rat was P11. The interval histogram shows the lack of very long intervals. C, As in A, except that the age of the rat was P28. Middle, Three complex waveforms; the middle one lacks an eAP. The bottom shows the interval histogram, showing smaller and less variable intervals than at the younger ages. D, Surface plot showing the age dependence of the event interval distribution in a total of 142 units. Sixty-three cells from Tritsch et al. (2010) within the P4–P8 range have been included. In each cell, the histogram is normalized to its largest value. Dashed gray line and arrow indicate hearing onset at P13. E, Developmental decrease in CV of event intervals. F, Developmental increase in average firing rate.