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Egocentric and allocentric representations in auditory cortex

Town, Stephen M.; Brimijoin, W. Owen; Bizley, Jennifer K.

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Authors

Stephen M. Town

W. Owen Brimijoin

Jennifer K. Bizley



Abstract

A key function of the brain is to provide a stable representation of an object’s location in the world. In hearing, sound azimuth and elevation are encoded by neurons throughout the auditory system, and auditory cortex is necessary for sound localization. However, the coordinate frame in which neurons represent sound space remains undefined: classical spatial receptive fields in head-fixed subjects can be explained either by sensitivity to sound source location relative to the head (egocentric) or relative to the world (allocentric encoding). This coordinate frame ambiguity can be resolved by studying freely moving subjects; here we recorded spatial receptive fields in the auditory cortex of freely moving ferrets. We found that most spatially tuned neurons represented sound source location relative to the head across changes in head position and direction. In addition, we also recorded a small number of neurons in which sound location was represented in a world-centered coordinate frame. We used measurements of spatial tuning across changes in head position and direction to explore the influence of sound source distance and speed of head movement on auditory cortical activity and spatial tuning. Modulation depth of spatial tuning increased with distance for egocentric but not allocentric units, whereas, for both populations, modulation was stronger at faster movement speeds. Our findings suggest that early auditory cortex primarily represents sound source location relative to ourselves but that a minority of cells can represent sound location in the world independent of our own position.

Citation

Town, S. M., Brimijoin, W. O., & Bizley, J. K. (in press). Egocentric and allocentric representations in auditory cortex. PLoS Biology, 15(6), Article e2001878. https://doi.org/10.1371/journal.pbio.2001878

Journal Article Type Article
Acceptance Date May 9, 2017
Online Publication Date Jun 15, 2017
Deposit Date Jul 19, 2017
Publicly Available Date Jul 19, 2017
Journal PLoS Biology
Print ISSN 1544-9173
Electronic ISSN 1545-7885
Publisher Public Library of Science
Peer Reviewed Peer Reviewed
Volume 15
Issue 6
Article Number e2001878
DOI https://doi.org/10.1371/journal.pbio.2001878
Public URL https://nottingham-repository.worktribe.com/output/866178
Publisher URL http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2001878
Additional Information Town SM, Brimijoin WO, Bizley JK (2017) Egocentric and allocentric representations in auditory cortex. PLoS
Biol 15(6): e2001878. https://doi.org/10.1371/journal.pbio.
2001878.
Contract Date Jul 19, 2017

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