ABSTRACT
Pitch is a critical dimension of human auditory perception, yet its neural bases are not well-understood, due to the multiplicity of neural codes available for extracting acoustic features relevant for pitch. One strategy for attacking this problem is to examine pitch extraction algorithms in an animal species where the contributions of different neural codes can be easily separated. This paper describes a possible mechanism for periodicity extraction in such a model system, the auditory system of anuran amphibians. Behavioral studies conducted with several anuran species show that these animals are sensitive to features of sounds that mediate pitch perception in humans. The anuran peripheral auditory system extracts periodicity cues from multiple-harmonic sounds primarily by time-domain processing. Eighth nerve fibers are sensitive to the amplitude envelope, harmonic structure, and phase structure of complex sounds, and transmit this information via arrays of phase-locked activity to the central auditory system, which may convert this timing information into a place representation.
