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Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells

One general categorization of retinal ganglion cells is to segregate them into tonically or phasically responding neurons, each conveying discrete aspects of the visual scene. Although best identified in the output signals of the retina, this distinction is initiated at the first synapse: between ph...

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Detalles Bibliográficos
Autores principales: Sethuramanujam, Santhosh, Slaughter, Malcolm M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4459976/
https://www.ncbi.nlm.nih.gov/pubmed/26053500
http://dx.doi.org/10.1371/journal.pone.0129133
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author Sethuramanujam, Santhosh
Slaughter, Malcolm M.
author_facet Sethuramanujam, Santhosh
Slaughter, Malcolm M.
author_sort Sethuramanujam, Santhosh
collection PubMed
description One general categorization of retinal ganglion cells is to segregate them into tonically or phasically responding neurons, each conveying discrete aspects of the visual scene. Although best identified in the output signals of the retina, this distinction is initiated at the first synapse: between photoreceptors and the dendrites of bipolar cells. In this study we found that the output synapses of bipolar cells also contribute to separate these pathways. Both transient and sustained ganglion cells can produce maintained spike activity, but bipolar cell glutamate release exhibits a divergence that corresponds to the response characteristics of the ganglion cells. Comparing light intensity coding in the sustained and transient ON pathways revealed that they shared the intensity spectrum. The transient pathway had greater sensitivity but smaller dynamic range, and switched from intensity coding to event detection at light levels where sustained pathway sensitivity began to rise. The distinctive properties of the sustained pathway depended upon inhibition and shifted toward those of the transient pathway in the absence of inhibition. The transient system was comparatively unaffected by the loss of inhibition and this was due to the concomitant activation of perisynaptic NMDA receptors. Overall, the properties of bipolar cell dendritic and axon terminals both contribute to the formation of key aspects of the sustained/transient dichotomy normally associated with ganglion cells.
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spelling pubmed-44599762015-06-16 Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells Sethuramanujam, Santhosh Slaughter, Malcolm M. PLoS One Research Article One general categorization of retinal ganglion cells is to segregate them into tonically or phasically responding neurons, each conveying discrete aspects of the visual scene. Although best identified in the output signals of the retina, this distinction is initiated at the first synapse: between photoreceptors and the dendrites of bipolar cells. In this study we found that the output synapses of bipolar cells also contribute to separate these pathways. Both transient and sustained ganglion cells can produce maintained spike activity, but bipolar cell glutamate release exhibits a divergence that corresponds to the response characteristics of the ganglion cells. Comparing light intensity coding in the sustained and transient ON pathways revealed that they shared the intensity spectrum. The transient pathway had greater sensitivity but smaller dynamic range, and switched from intensity coding to event detection at light levels where sustained pathway sensitivity began to rise. The distinctive properties of the sustained pathway depended upon inhibition and shifted toward those of the transient pathway in the absence of inhibition. The transient system was comparatively unaffected by the loss of inhibition and this was due to the concomitant activation of perisynaptic NMDA receptors. Overall, the properties of bipolar cell dendritic and axon terminals both contribute to the formation of key aspects of the sustained/transient dichotomy normally associated with ganglion cells. Public Library of Science 2015-06-08 /pmc/articles/PMC4459976/ /pubmed/26053500 http://dx.doi.org/10.1371/journal.pone.0129133 Text en © 2015 Sethuramanujam, Slaughter http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Sethuramanujam, Santhosh
Slaughter, Malcolm M.
Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells
title Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells
title_full Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells
title_fullStr Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells
title_full_unstemmed Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells
title_short Properties of a Glutamatergic Synapse Controlling Information Output from Retinal Bipolar Cells
title_sort properties of a glutamatergic synapse controlling information output from retinal bipolar cells
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4459976/
https://www.ncbi.nlm.nih.gov/pubmed/26053500
http://dx.doi.org/10.1371/journal.pone.0129133
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