Re: [AUDITORY] Seeking advice on using ANF firing rate to reslove front-back confusion in sound localization model

Subject: Re: [AUDITORY] Seeking advice on using ANF firing rate to reslove front-back confusion in sound localization model

From: Jan Schnupp <000000e042a1ec30-dmarc-request@xxxxxxxxxxxxxxx>

Date: Wed, 26 Feb 2025 14:26:43 +0800

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Comments: To: Qin Liu <qin.liu@xxxxxxx>

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Reply-to: Jan Schnupp <jan.schnupp@xxxxxxxxxxxxxx>

Sender: AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxxxxxxxxx>

Dear Qin,

I do not think your problem is solvable without some kind of assumptions about HRTF and/or cross-frequency integration.

I am also confused about the fact that you are looking ant ANF rates and MSO, as MSO is usually thought of as a structure interested in fine timing rather than temporally coarse rates.

And presumably, if your current solution can't do front-back, then I assume you can't do top and bottom either?

In any event, whether you look at either ILDs or ITDs in any one frequency band, these will only narrow down source directions to one specific cone of confusion.

And you cannot do better unless you incorporate at least some knowledge or assumption about what the shapes of these cones are and how they differ for each cue and frequency band, and combine info across frequencies accordingly, in a sense by discounting directions where the solution cones do not intersect and favoring directions where they do.

Jan

---------------------------------------

Prof Jan Schnupp

Gerald Choa Neuroscience Institute

The Chinese University of Hong Kong

Sha Tin

Hong Kong

https://auditoryneuroscience.com

http://jan.schnupp.net

On Wed, 26 Feb 2025 at 13:23, Qin Liu <000003c563e12bd3-dmarc-request@xxxxxxxxxxxxxxx> wrote:

Dear auditory list,

I am currently working on a project involving sound localization using firing rates from auditory nerve fibers (ANFs) and the medial superior olive (MSO). However, I have encountered an issue: I am unable to distinguish between front and back sound sources using MSO firing rates alone but only the left-right.

I am considering whether auditory nerve fiber (ANF) firing rates might provide a solution, but I am uncertain how to utilize them effectively. For instance, I have experimented with analyzing the positive gradients of ANF firing rates but have not yet achieved meaningful results.

Could anyone suggest an auditory metric derived from binaural signals, ANF firing rates, or MSO that could classify front/back sources without relying on HRTF template matching? Any insights or alternative approaches would be invaluable to my work.

Thank you in advance. I sincerely appreciate any guidance you can offer.

Best regards,

Qin Liu
Doctoral Student
Laboratory of Wave Engineering, École Polytechnique Fédérale de Lausanne (EPFL)
Email: qin.liu@xxxxxxx