The role of canonical neural computations in sound localization
File(s)
Author(s)
Lestang, Jean-Hugues
Type
Thesis or dissertation
Abstract
Localizing sounds is an important ability for many species. However, reverberative sounds
present a significant challenge to the auditory system as later arriving reverberations may carry
confounding localization cues. The ’precedence effect’ refers to a set of perceptual behaviours
related to this situation. Studies investigating the precedence effect observed that the auditory
system tends to focus the core of the localization process on the computation of localization
cues carried by the first arriving sound. Doing so relieves the auditory system from dealing
with contradictory localization cues in later arriving sounds. A recent study by Dietz et al.
(2013) confirmed that human listeners use this approach to deal with dynamic localization
cues. In order to provide an explanation for this finding, we first tested several auditory models
on the specific task described in Dietz et al. (2013) in order to shortlist possible mechanisms
capable of accounting for the early extraction of temporal binaural cues. We found that the
best candidates to account for this data are single cell mechanisms, such as adaptation and
onset firing, as well as inhibitory population mechanisms. To further understand how each
mechanism contributes to the suppression of lagging sounds, we designed more general models
capable of demonstrating the principal features of each mechanism. We tested these models
thoroughly and found that all mechanisms were able to reproduce the results over a wide range
of parameters. This finding suggests that mechanisms responsible for the precedence effect
may not be specialized to perform this specific task but instead may be the results of more
commonly found neural circuits in the brain. Finally, to facilitate comparing the performance
of auditory models on psychoacoustical data, we also designed and implemented an auditory
modelling framework capable of addressing many challenges existing in the field of auditory
modelling.
present a significant challenge to the auditory system as later arriving reverberations may carry
confounding localization cues. The ’precedence effect’ refers to a set of perceptual behaviours
related to this situation. Studies investigating the precedence effect observed that the auditory
system tends to focus the core of the localization process on the computation of localization
cues carried by the first arriving sound. Doing so relieves the auditory system from dealing
with contradictory localization cues in later arriving sounds. A recent study by Dietz et al.
(2013) confirmed that human listeners use this approach to deal with dynamic localization
cues. In order to provide an explanation for this finding, we first tested several auditory models
on the specific task described in Dietz et al. (2013) in order to shortlist possible mechanisms
capable of accounting for the early extraction of temporal binaural cues. We found that the
best candidates to account for this data are single cell mechanisms, such as adaptation and
onset firing, as well as inhibitory population mechanisms. To further understand how each
mechanism contributes to the suppression of lagging sounds, we designed more general models
capable of demonstrating the principal features of each mechanism. We tested these models
thoroughly and found that all mechanisms were able to reproduce the results over a wide range
of parameters. This finding suggests that mechanisms responsible for the precedence effect
may not be specialized to perform this specific task but instead may be the results of more
commonly found neural circuits in the brain. Finally, to facilitate comparing the performance
of auditory models on psychoacoustical data, we also designed and implemented an auditory
modelling framework capable of addressing many challenges existing in the field of auditory
modelling.
Version
Open Access
Date Issued
2019-09
Date Awarded
2019-12
Copyright Statement
Creative Commons Attribution NonCommercial NoDerivatives Licence
Advisor
Goodman, Daniel
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
Electrical and Electronic Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)