Local Cochlear Correlations of Perceived Pitch

Abstract

Pitch is one of the most salient attributes of the human perception of sound, but is still not well understood. This difficulty originates in the entwined nature of the phenomenon, in which a physical stimulus as well as a psychophysiological signal receiver are involved. In an electronic realization of a biophysically detailed nonlinear model of the cochlea, we find local cochlear correlates of the perceived pitch that explain all essential pitch-shifting phenomena from physical grounds.

Auditory Power-Law Activation Avalanches Exhibit a Fundamental Computational Ground State

“…This model reproduces virtually all mesoscopic biophysical cochlear observations ( [16][17][18][19][20]; in particular Supplemental Material of Refs. [16,18,19]). Fundamental for this is that the sections share the dynamical properties of the microscopic amplification-providing outer hair cells [14,21], which is well modeled by a stimulated Hopf process:…”

“…Based on the detailed biophysics and nonlinear dynamics at work in the cochlea [13,14], we developed a model of the sensor consisting of such sections [16][17][18]. This model reproduces virtually all mesoscopic biophysical cochlear observations ( [16][17][18][19][20]; in particular Supplemental Material of Refs.…”

“…At values μ < 0, the system is below bifurcation to self-oscillation but responds towards stimulation signals FðtÞ as a small-signal amplifier [24,25]. Dissipation by fluidal viscous losses can be described by tailored sixth-order Butterworth low-pass filters [17,18]. The main characteristics of the isolated node dynamics are collected in Fig.…”

“…Figure 2 exhibits the activation network from the input of two complex tones (our complex tones always consist of five consecutive harmonics, starting with the fundamental frequency). Activated nodes relate either to a harmonic of a stimulation or to a combination tone of already activated nodes; combination tones have a prominent role in human pitch perception [18,19,28,29]. A 0.65-kHz tone, e.g., is generated as the 2f 1 − f 2 combination tone, with f 1;2 ¼ f2; 3.35g kHz.…”

Implementation of a digital evaluation platform to analyze bifurcation based nonlinear amplifiers

“…Each cochlea section includes a Hopf-type amplifier. The analog prototype reproduces the high sensitivity and compressive nonlinearity as well as the two-tone suppression and combination-tone generation with high precision (Stoop et al, 2007;Martignoli and Stoop, 2010). Each of them describes a characteristic feature of the cochlea.…”