Natural ITD statistics predict human auditory spatial perception.

Rodrigo Pavão,Elyse S Sussman,Brian J Fischer,José L Peña

doi:10.7554/elife.51927

Rodrigo Pavão, Elyse S Sussman + Show 2 more

Open Access

https://doi.org/10.7554/elife.51927

Copy DOI

Journal: eLife	Publication Date: Oct 12, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: Albert Einstein College of Medicine, Seattle University

Abstract

A neural code adapted to the statistical structure of sensory cues may optimize perception. We investigated whether interaural time difference (ITD) statistics inherent in natural acoustic scenes are parameters determining spatial discriminability. The natural ITD rate of change across azimuth (ITDrc) and ITD variability over time (ITDv) were combined in a Fisher information statistic to assess the amount of azimuthal information conveyed by this sensory cue. We hypothesized that natural ITD statistics underlie the neural code for ITD and thus influence spatial perception. To test this hypothesis, sounds with invariant statistics were presented to measure human spatial discriminability and spatial novelty detection. Human auditory spatial perception showed correlation with natural ITD statistics, supporting our hypothesis. Further analysis showed that these results are consistent with classic models of ITD coding and can explain the ITD tuning distribution observed in the mammalian brainstem.

Highlights

Humans and other species localize sound sources in the horizontal plane using sub-millisecond interaural time difference (ITD) between signals arriving at the two ears (Middlebrooks and Green 1991)
ITD statistics estimated from human HRTFs and properties of cochlear filters To test the hypothesis that natural ITD statistics influence the neural code underlying sound localization, we estimated
Our study proposes a new factor influencing the amount of spatial information carried by auditory stimuli, the ITD variability over time (ITDv)

Summary

Introduction

Humans and other species localize sound sources in the horizontal plane using sub-millisecond interaural time difference (ITD) between signals arriving at the two ears (Middlebrooks and Green 1991). Classical psychophysical studies demonstrated that humans detect sound location better in the front than in the periphery (Mills 1958; Yost 1974; Makous and Middlebrooks 1990). Better sound discrimination and localization in frontal locations can be predicted from the geometry of the head and the placing of the ears, causing higher ITD rate of change as a function of azimuth in the front (Woodworth 1938; Feddersen et al 1957; Gelfand 2016; Brown et al 2018)

Methods

Results

Conclusion