Periodicity Pitch Perception

Abstract

This study presents a computational model to reproduce the biological dynamics of "listening to music." A biologically plausible model of periodicity pitch detection is proposed and simulated. Periodicity pitch is computed across a range of the auditory spectrum. Periodicity pitch is detected from subsets of activated auditory nerve fibers (ANFs). These activate connected model octopus cells, which trigger model neurons detecting onsets and offsets; thence model interval-tuned neurons are innervated at the right interval times; and finally, a set of common interval-detecting neurons indicate pitch. Octopus cells rhythmically spike with the pitch periodicity of the sound. Batteries of interval-tuned neurons stopwatch-like measure the inter-spike intervals of the octopus cells by coding interval durations as first spike latencies (FSLs). The FSL-triggered spikes synchronously coincide through a monolayer spiking neural network at the corresponding receiver pitch neurons.

Periodicity Pitch Perception Part III: Sensibility and Pachinko Volatility

“…This corresponds to the maximum return time of 2 ms. The constant delay is derived from the Poisson firing statistics of octopus cells and was determined in Aubie's modified model as 18 μs standard deviation (SDEV) (Klefenz and Harczos, 2020 ). The dendritic path lengths are expressed as n delays ( D ) with a uniform delay constant D of 18 μs.…”

“…High-fidelity audio recording and playback technologies use a minimum standard sampling rate of 44.1 kHz. How auditory neuron ensembles cope with this sampling rate was not clear until recently, when a computational neuroscience model illustrated periodic pitch perception on a microsecond scale (Klefenz and Harczos, 2020 ). In the model, equilibrium tipping points are evoked by an excess of excitatory vesicles relative to the currently available reservoir of inhibitory vesicles at the soma of inferior colliculus (IC) neurons and recorded with extreme temporal precision.…”

“…The inter-spike intervals (ISI) of octopus cells are measured by batteries of interval-tuned neurons (ITNs) by encoding the interval durations as first spike latencies (FSLs) (Aubie et al, 2009 , 2012 ). Aubie's model is formulated in NEURON with excitatory NMDAR/AMPAR GABAergic inhibition 1 (Kopp-Scheinpflug et al, 2018 ) and has been adapted and optimized to work reliably in the microsecond range (Klefenz and Harczos, 2020 ). For better understanding, some parts of the two articles in the Periodicity Pitch Perception series (Harczos and Klefenz, 2018 ; Klefenz and Harczos, 2020 ) are recapitulated and some of the figures are reprinted.…”

“…The model and our hypothesis is tested with two audio samples taken from the Fraunhofer dataset also used in Klefenz and Harczos ( 2020 ) for terms of comparability. The first one is a recording of a female singer, who sings the vowel “a” with a pitch of C4 (261Hz) and the second a pure sine tone with the same pitch.…”

“…This wiring scheme represents a local receptive field for each octopus' cell. Adjacent receptive fields partially overlap and share multiple ANFs as inputs (Klefenz and Harczos, 2020 ).…”