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Extraretinal Spike Normalization in Retinal Ganglion Cell Axons

Spike conduction velocity characteristically differs between myelinated and unmyelinated axons. Here we test whether spikes of myelinated and unmyelinated paths differ in other respects by measuring rat retinal ganglion cell (RGC) spike duration in the intraretinal, unmyelinated nerve fiber layer an...

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Autores principales: Fogli Iseppe, Alex, Ogata, Genki, Johnson, Jeffrey S., Partida, Gloria J., Johnson, Nicholas, Passaglia, Christopher L., Ishida, Andrew T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Society for Neuroscience 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7110362/
https://www.ncbi.nlm.nih.gov/pubmed/32086286
http://dx.doi.org/10.1523/ENEURO.0504-19.2020
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author Fogli Iseppe, Alex
Ogata, Genki
Johnson, Jeffrey S.
Partida, Gloria J.
Johnson, Nicholas
Passaglia, Christopher L.
Ishida, Andrew T.
author_facet Fogli Iseppe, Alex
Ogata, Genki
Johnson, Jeffrey S.
Partida, Gloria J.
Johnson, Nicholas
Passaglia, Christopher L.
Ishida, Andrew T.
author_sort Fogli Iseppe, Alex
collection PubMed
description Spike conduction velocity characteristically differs between myelinated and unmyelinated axons. Here we test whether spikes of myelinated and unmyelinated paths differ in other respects by measuring rat retinal ganglion cell (RGC) spike duration in the intraretinal, unmyelinated nerve fiber layer and the extraretinal, myelinated optic nerve and optic chiasm. We find that rapid spike firing and illumination broaden spikes in intraretinal axons but not in extraretinal axons. RGC axons thus initiate spikes intraretinally and normalize spike duration extraretinally. Additionally, we analyze spikes that were recorded in a previous study of rhesus macaque retinogeniculate transmission and find that rapid spike firing does not broaden spikes in optic tract. The spike normalization we find reduces the number of spike properties that can change during RGC light responses. However, this is not because identical spikes fire in all axons. Instead, our recordings show that different subtypes of RGC generate axonal spikes of different durations and that the differences resemble spike duration increases that alter neurotransmitter release from other neurons. Moreover, previous studies have shown that RGC spikes of shorter duration can fire at higher maximum frequencies. These properties should facilitate signal transfer by different mechanisms at RGC synapses onto subcortical target neurons.
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spelling pubmed-71103622020-04-01 Extraretinal Spike Normalization in Retinal Ganglion Cell Axons Fogli Iseppe, Alex Ogata, Genki Johnson, Jeffrey S. Partida, Gloria J. Johnson, Nicholas Passaglia, Christopher L. Ishida, Andrew T. eNeuro Research Article: New Research Spike conduction velocity characteristically differs between myelinated and unmyelinated axons. Here we test whether spikes of myelinated and unmyelinated paths differ in other respects by measuring rat retinal ganglion cell (RGC) spike duration in the intraretinal, unmyelinated nerve fiber layer and the extraretinal, myelinated optic nerve and optic chiasm. We find that rapid spike firing and illumination broaden spikes in intraretinal axons but not in extraretinal axons. RGC axons thus initiate spikes intraretinally and normalize spike duration extraretinally. Additionally, we analyze spikes that were recorded in a previous study of rhesus macaque retinogeniculate transmission and find that rapid spike firing does not broaden spikes in optic tract. The spike normalization we find reduces the number of spike properties that can change during RGC light responses. However, this is not because identical spikes fire in all axons. Instead, our recordings show that different subtypes of RGC generate axonal spikes of different durations and that the differences resemble spike duration increases that alter neurotransmitter release from other neurons. Moreover, previous studies have shown that RGC spikes of shorter duration can fire at higher maximum frequencies. These properties should facilitate signal transfer by different mechanisms at RGC synapses onto subcortical target neurons. Society for Neuroscience 2020-03-19 /pmc/articles/PMC7110362/ /pubmed/32086286 http://dx.doi.org/10.1523/ENEURO.0504-19.2020 Text en Copyright © 2020 Fogli Iseppe et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
spellingShingle Research Article: New Research
Fogli Iseppe, Alex
Ogata, Genki
Johnson, Jeffrey S.
Partida, Gloria J.
Johnson, Nicholas
Passaglia, Christopher L.
Ishida, Andrew T.
Extraretinal Spike Normalization in Retinal Ganglion Cell Axons
title Extraretinal Spike Normalization in Retinal Ganglion Cell Axons
title_full Extraretinal Spike Normalization in Retinal Ganglion Cell Axons
title_fullStr Extraretinal Spike Normalization in Retinal Ganglion Cell Axons
title_full_unstemmed Extraretinal Spike Normalization in Retinal Ganglion Cell Axons
title_short Extraretinal Spike Normalization in Retinal Ganglion Cell Axons
title_sort extraretinal spike normalization in retinal ganglion cell axons
topic Research Article: New Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7110362/
https://www.ncbi.nlm.nih.gov/pubmed/32086286
http://dx.doi.org/10.1523/ENEURO.0504-19.2020
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