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Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei

A direct retinal projection targets the suprachiasmatic nucleus (SCN) (an important hypothalamic control center). The accepted function of this projection is to convey information about ambient light (irradiance) to synchronize the SCN’s endogenous circadian clock with local time and drive the diurn...

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Autores principales: Mouland, Joshua W., Stinchcombe, Adam R., Forger, Daniel B., Brown, Timothy M., Lucas, Robert J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cell Press 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5462621/
https://www.ncbi.nlm.nih.gov/pubmed/28528901
http://dx.doi.org/10.1016/j.cub.2017.04.039
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author Mouland, Joshua W.
Stinchcombe, Adam R.
Forger, Daniel B.
Brown, Timothy M.
Lucas, Robert J.
author_facet Mouland, Joshua W.
Stinchcombe, Adam R.
Forger, Daniel B.
Brown, Timothy M.
Lucas, Robert J.
author_sort Mouland, Joshua W.
collection PubMed
description A direct retinal projection targets the suprachiasmatic nucleus (SCN) (an important hypothalamic control center). The accepted function of this projection is to convey information about ambient light (irradiance) to synchronize the SCN’s endogenous circadian clock with local time and drive the diurnal variations in physiology and behavior [1, 2, 3, 4]. Here, we report that it also renders the SCN responsive to visual images. We map spatial receptive fields (RFs) for SCN neurons and find that only a minority are excited (or inhibited) by light from across the scene as expected for irradiance detectors. The most commonly encountered units have RFs with small excitatory centers, combined with very extensive inhibitory surrounds that reduce their sensitivity to global changes in light in favor of responses to spatial patterns. Other units have larger excitatory RF centers, but these always cover a coherent region of visual space, implying visuotopic order at the single-unit level. Approximately 75% of light-responsive SCN units modulate their firing according to simple spatial patterns (drifting or inverting gratings) without changes in irradiance. The time-averaged firing rate of the SCN is modestly increased under these conditions, but including spatial contrast did not significantly alter the circadian phase resetting efficiency of light. Our data indicate that the SCN contains information about irradiance and spatial patterns. This newly appreciated sensory capacity provides a mechanism by which behavioral and physiological systems downstream of the SCN could respond to visual images [5].
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spelling pubmed-54626212017-06-15 Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei Mouland, Joshua W. Stinchcombe, Adam R. Forger, Daniel B. Brown, Timothy M. Lucas, Robert J. Curr Biol Report A direct retinal projection targets the suprachiasmatic nucleus (SCN) (an important hypothalamic control center). The accepted function of this projection is to convey information about ambient light (irradiance) to synchronize the SCN’s endogenous circadian clock with local time and drive the diurnal variations in physiology and behavior [1, 2, 3, 4]. Here, we report that it also renders the SCN responsive to visual images. We map spatial receptive fields (RFs) for SCN neurons and find that only a minority are excited (or inhibited) by light from across the scene as expected for irradiance detectors. The most commonly encountered units have RFs with small excitatory centers, combined with very extensive inhibitory surrounds that reduce their sensitivity to global changes in light in favor of responses to spatial patterns. Other units have larger excitatory RF centers, but these always cover a coherent region of visual space, implying visuotopic order at the single-unit level. Approximately 75% of light-responsive SCN units modulate their firing according to simple spatial patterns (drifting or inverting gratings) without changes in irradiance. The time-averaged firing rate of the SCN is modestly increased under these conditions, but including spatial contrast did not significantly alter the circadian phase resetting efficiency of light. Our data indicate that the SCN contains information about irradiance and spatial patterns. This newly appreciated sensory capacity provides a mechanism by which behavioral and physiological systems downstream of the SCN could respond to visual images [5]. Cell Press 2017-06-05 /pmc/articles/PMC5462621/ /pubmed/28528901 http://dx.doi.org/10.1016/j.cub.2017.04.039 Text en © 2017 The Authors http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Report
Mouland, Joshua W.
Stinchcombe, Adam R.
Forger, Daniel B.
Brown, Timothy M.
Lucas, Robert J.
Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei
title Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei
title_full Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei
title_fullStr Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei
title_full_unstemmed Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei
title_short Responses to Spatial Contrast in the Mouse Suprachiasmatic Nuclei
title_sort responses to spatial contrast in the mouse suprachiasmatic nuclei
topic Report
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5462621/
https://www.ncbi.nlm.nih.gov/pubmed/28528901
http://dx.doi.org/10.1016/j.cub.2017.04.039
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