Information Transmission in the Auditory Brainstem Figure 1. Enhancement of synchrony and rate relative to auditory nerve in chinchilla and cat. Panels A and B display dot raster plots for the responses of an auditory nerve fiber and a cochlear nucleus neuron, respectively, in chinchilla. Only the neural responses obtained in the last 20 stimulus presentations are shown. Stimulus waveforms with an arbitrary phase are superimposed on panels A and B (continuous traces). Panels C and D contain period histograms obtained from responses to CF tones of the ANF and the VCN neuron, respectively. Panels E and F display period histograms obtained from responses of one ANF and one VCN neuron, respectively, in cat. Power spectrum densities (PSDs) of the responses shown in A and B are displayed in the insets C and D, respectively. The first dot in every inset is placed at the frequency corresponding to CF ( = f0). Period histograms were shifted to make their maximum value occur at 0.5. doi:10.1371/journal.pone.0044286.g001 neuron to follow the stimulus period compared to the ANF, which translates to a higher firing rate for the VCN neuron, especially for stimulus levels above 40 dB SPL. The same observation applies to the results in the cat (insets in Figs. 2E and 2F). In response to certain above-CF tones, VCN neurons in Fig. 2 fire more vigorously near the response onset (i.e., before 20 ms) than during the steady-state part. This behavior is clearly seen in the dot raster plot of the responses to 800-Hz tones of the neuron in the Fig. 2D inset. For stimulus levels above 40–50 dB SPL, PLOS ONE | www.plosone.org 4 September 2012 | Volume 7 | Issue 9 | e44286