PT  - JOURNAL ARTICLE
AU  - Jonathan Laudanski
AU  - Yi Zheng
AU  - Romain Brette
TI  - A structural theory of pitch
AID  - 10.1523/ENEURO.0033-14.2014
DP  - 2014 Nov 12
TA  - eneuro
PG  - ENEURO.0033-14.2014
4099  - http://www.eneuro.org/content/early/2014/11/18/ENEURO.0033-14.2014.short
4100  - http://www.eneuro.org/content/early/2014/11/18/ENEURO.0033-14.2014.full
AB  - Musical notes can be ordered from low to high along a perceptual dimension called « pitch ». A characteristic property of these sounds is their periodic waveform, and periodicity generally correlates with pitch. Thus pitch is often described as the perceptual correlate of the periodicity of the sound’s waveform. However, the existence and salience of pitch also depends in a complex way on other factors, in particular harmonic content: for example, periodic sounds made of high-order harmonics tend to have a weaker pitch than those made of low-order harmonics. Here we examine the theoretical proposition that pitch is the perceptual correlate of the regularity structure of the vibration pattern of the basilar membrane, across place and time - a generalization of the traditional view on pitch. While this proposition also attributes pitch to periodic sounds, we show that it predicts differences between resolved and unresolved harmonic complexes and a complex domain of existence of pitch, in agreement with psychophysical experiments. We also present a possible neural mechanism for pitch estimation based on coincidence detection, which does not require long delays, in contrast with standard temporal models of pitch. Significance statement: Melodies are composed of sounds that can be ordered on a musical scale. “Pitch” is the perceptual dimension on that scale. To a large extent, the periodicity of the sound’s waveform can be mapped to pitch. However, the existence and strength of pitch also depends on the harmonic content sounds, i.e., their timbre, which does not fit with this simple view. We propose to explain these observations by the fact that the input to the auditory system is the spatio-temporal vibration of the basilar membrane in the cochlea, rather than the acoustic waveform. We show that defining pitch as the regularity structure of that vibration can explain some aspects of the complexity of pitch perception.