Human pitch is pre-cortical: The essential role of the cochlear fluid

TL;DR

This paper demonstrates that human pitch perception, including complex psychoacoustic phenomena, can be explained by a minimal biophysical cochlear model emphasizing the role of cochlear fluid, challenging the cortical processing assumption.

Contribution

It introduces a purely biophysical cochlear model that reproduces psychoacoustic pitch-shift data, highlighting the cochlear fluid's essential role in pitch perception.

Findings

Reproduces psychoacoustic pitch-shift data from a cochlear model.

Shows cochlear fluid's critical role in pitch perception.

Challenges cortical processing theories of pitch perception.

Abstract

The perceived pitch of a complex harmonic sound changes if the partials of the sound are frequency-shifted by a fixed amount. Simple mathematical rules that the perceived pitch could be expected to follow ('first pitch-shift') are violated in psychoacoustic experiments ('second pitchshift'). For this, commonly cognitive cortical processes were held responsible. Here, we show that human pitch perception can be reproduced from a minimal, purely biophysical, model of the cochlea, by fully recovering the psychoacoustical pitch-shift data of G.F. Smoorenburg (1970) and related physiological measurements from the cat cochlear nucleus. For this to happen, the cochlear fluid plays a distinguished role.