Brainstem firing rate depends on absolute frequency, unlike the auditory nerve

Evidence

An important qualifier is that the entracking observed is not always the extreme form (exactly 1 spike/cycle), particularly at frequencies above a few 100 Hz. The defining property is that there is an effect of absolute frequency on average firing rate so that rate increases monotonically with frequency up to a certain maximum. Thus, in the brainstem, firing rate does not only depend on SPL and stimulus frequency relative to CF, as it does in the AN, but also depends on absolute stimulus frequency. For the extreme cases of this behavior a stronger statement can be made: SPL and stimulus frequency relative to CF have remarkably little effect, and absolute frequency is the overriding stimulus parameter determining response rate. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4494