Auditory nerve phase locking can encode slow waveform fluctuations across filters

Evidence

A temporal code based on consistent periodicities could represent these two frequencies easily — the auditory nerve can phase lock to these low frequencies. As the auditory filter frequency increases, however, interactions between components begin to occur and the output waveforms no longer appear sinusoidal. The waveform outputs of the 1300- and 3000-Hz auditory filters contain multiple frequencies leading to a modulated waveform having slow and fast fluctuations. A temporal code would have the ability to represent the slow fluctuations, as the auditory nerve would phase lock to the fundamental frequency. Note that these filtered waveforms repeat at the same rate as the 100-Hz tone, and their 10-ms periods are illustrated in Figure 6–8. Synchrony in the output waveforms across multiple auditory filters could provide a very robust code for the period (and therefore the pitch) of a sound. Psychophysical models capture the temporal synchrony across frequency bands in the form of acrossfrequency autocorrelation, which determines the periodicities present in the stimulus and captures whether those periodicities are coherent across frequency. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1231

Categorization

• DEFINE: Introduces across-frequency autocorrelation as the model capturing temporal synchrony in pitch.