Fundamental frequency is coded dually via harmonics and envelope rate

Evidence

Taking these results together, we note that auditory nerve fibers may phase lock to pure tones, as long at their characteristic frequencies are below 3 to 5 kHz. For pure tones, then, the temporal code is a low-frequency phenomenon. For complex tones, however, the temporal code is present in both highand low-frequency fibers. … Given that fundamental frequency is represented as individual harmonics but also in the repetition rate, both highand low-frequency auditory nerve fibers can code for the fundamental frequency. Low-frequency fibers will phase lock to individual harmonic components, whereas high-frequency fibers will phase lock to the fluctuation rate of the envelope. Psychophysically, this temporal code is implemented as an autocorrelation function, which is discussed in the next section. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1218

Categorization

• XREF: The dual coding of F0 (place via harmonics, temporal via envelope) connects to the classic ‘residue’ or ‘missing fundamental’ literature and to cochlear-implant coding design.