Midbrain local circuits shape sound intensity codes

Hierarchical processing of sensory information requires interaction at multiple levels along the peripheral to central pathway. Recent evidence suggests that interaction between driving and modulating components can shape both top down and bottom up processing of sensory information. Here we show th...

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Main Authors:	Grimsley, Calum Alex, Sanchez, Jason Tait, Sivaramakrishnan, Shobhana
Format:	Online
Language:	English
Published:	Frontiers Media S.A. 2013
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3812908/

id	pubmed-3812908
recordtype	oai_dc
spelling	pubmed-38129082013-11-06 Midbrain local circuits shape sound intensity codes Grimsley, Calum Alex Sanchez, Jason Tait Sivaramakrishnan, Shobhana Neuroscience Hierarchical processing of sensory information requires interaction at multiple levels along the peripheral to central pathway. Recent evidence suggests that interaction between driving and modulating components can shape both top down and bottom up processing of sensory information. Here we show that a component inherited from extrinsic sources combines with local components to code sound intensity. By applying high concentrations of divalent cations to neurons in the nucleus of the inferior colliculus in the auditory midbrain, we show that as sound intensity increases, the source of synaptic efficacy changes from inherited inputs to local circuits. In neurons with a wide dynamic range response to intensity, inherited inputs increase firing rates at low sound intensities but saturate at mid-to-high intensities. Local circuits activate at high sound intensities and widen dynamic range by continuously increasing their output gain with intensity. Inherited inputs are necessary and sufficient to evoke tuned responses, however local circuits change peak output. Push–pull driving inhibition and excitation create net excitatory drive to intensity-variant neurons and tune neurons to intensity. Our results reveal that dynamic range and tuning re-emerge in the auditory midbrain through local circuits that are themselves variable or tuned. Frontiers Media S.A. 2013-10-30 /pmc/articles/PMC3812908/ /pubmed/24198763 http://dx.doi.org/10.3389/fncir.2013.00174 Text en Copyright © 2013 Grimsley, Sanchez and Sivaramakrishnan. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Grimsley, Calum Alex Sanchez, Jason Tait Sivaramakrishnan, Shobhana
spellingShingle	Grimsley, Calum Alex Sanchez, Jason Tait Sivaramakrishnan, Shobhana Midbrain local circuits shape sound intensity codes
author_facet	Grimsley, Calum Alex Sanchez, Jason Tait Sivaramakrishnan, Shobhana
author_sort	Grimsley, Calum Alex
title	Midbrain local circuits shape sound intensity codes
title_short	Midbrain local circuits shape sound intensity codes
title_full	Midbrain local circuits shape sound intensity codes
title_fullStr	Midbrain local circuits shape sound intensity codes
title_full_unstemmed	Midbrain local circuits shape sound intensity codes
title_sort	midbrain local circuits shape sound intensity codes
description	Hierarchical processing of sensory information requires interaction at multiple levels along the peripheral to central pathway. Recent evidence suggests that interaction between driving and modulating components can shape both top down and bottom up processing of sensory information. Here we show that a component inherited from extrinsic sources combines with local components to code sound intensity. By applying high concentrations of divalent cations to neurons in the nucleus of the inferior colliculus in the auditory midbrain, we show that as sound intensity increases, the source of synaptic efficacy changes from inherited inputs to local circuits. In neurons with a wide dynamic range response to intensity, inherited inputs increase firing rates at low sound intensities but saturate at mid-to-high intensities. Local circuits activate at high sound intensities and widen dynamic range by continuously increasing their output gain with intensity. Inherited inputs are necessary and sufficient to evoke tuned responses, however local circuits change peak output. Push–pull driving inhibition and excitation create net excitatory drive to intensity-variant neurons and tune neurons to intensity. Our results reveal that dynamic range and tuning re-emerge in the auditory midbrain through local circuits that are themselves variable or tuned.
publisher	Frontiers Media S.A.
publishDate	2013
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3812908/
_version_	1612021830231523328

Midbrain local circuits shape sound intensity codes

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