Spectro-temporal templates unify the pitch of resolved and unresolved harmonics

Abstract

Pitch is a fundamental attribute in auditory perception that is involved in source identification and segregation, music, and speech understanding. When harmonics are well-resolved, the induced pitch is usually salient and precise; however, when the harmonics are not completely resolved, the pitch percept becomes less salient and poorly discriminated. Previous models relying on harmonic spectral templates have been able to account fully for the pitch of the resolved but not of the unresolved harmonics. I will describe a biologically motivated model of templates that combine both spectral and temporal cues to estimate both pitch percepts. Specifically, the pitch of unresolved harmonics is estimated through bandpass filters implemented by resonances in the dendritic trees of neurons in the early auditory pathway. It is demonstrated that organizing and exploiting such dendritic tuning can arise spontaneously even in response to white noise. We show how these temporal cues become integrated with those of spectrally resolved harmonics, effectively creating spectro-temporal harmonic templates for all pitch percepts. We finally discuss how this approach can account for all major monaural pitch percepts, as well as pitch percepts evoked by dichotic binaural stimuli.