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Using light to tell the time of day: sensory coding in the mammalian circadian visual network

Circadian clocks are a near-ubiquitous feature of biology, allowing organisms to optimise their physiology to make the most efficient use of resources and adjust behaviour to maximise survival over the solar day. To fulfil this role, circadian clocks require information about time in the external wo...

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Autor principal: Brown, Timothy M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Company of Biologists Ltd 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4920240/
https://www.ncbi.nlm.nih.gov/pubmed/27307539
http://dx.doi.org/10.1242/jeb.132167
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author Brown, Timothy M.
author_facet Brown, Timothy M.
author_sort Brown, Timothy M.
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description Circadian clocks are a near-ubiquitous feature of biology, allowing organisms to optimise their physiology to make the most efficient use of resources and adjust behaviour to maximise survival over the solar day. To fulfil this role, circadian clocks require information about time in the external world. This is most reliably obtained by measuring the pronounced changes in illumination associated with the earth's rotation. In mammals, these changes are exclusively detected in the retina and are relayed by direct and indirect neural pathways to the master circadian clock in the hypothalamic suprachiasmatic nuclei. Recent work reveals a surprising level of complexity in this sensory control of the circadian system, including the participation of multiple photoreceptive pathways conveying distinct aspects of visual and/or time-of-day information. In this Review, I summarise these important recent advances, present hypotheses as to the functions and neural origins of these sensory signals, highlight key challenges for future research and discuss the implications of our current knowledge for animals and humans in the modern world.
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spelling pubmed-49202402016-07-25 Using light to tell the time of day: sensory coding in the mammalian circadian visual network Brown, Timothy M. J Exp Biol Review Circadian clocks are a near-ubiquitous feature of biology, allowing organisms to optimise their physiology to make the most efficient use of resources and adjust behaviour to maximise survival over the solar day. To fulfil this role, circadian clocks require information about time in the external world. This is most reliably obtained by measuring the pronounced changes in illumination associated with the earth's rotation. In mammals, these changes are exclusively detected in the retina and are relayed by direct and indirect neural pathways to the master circadian clock in the hypothalamic suprachiasmatic nuclei. Recent work reveals a surprising level of complexity in this sensory control of the circadian system, including the participation of multiple photoreceptive pathways conveying distinct aspects of visual and/or time-of-day information. In this Review, I summarise these important recent advances, present hypotheses as to the functions and neural origins of these sensory signals, highlight key challenges for future research and discuss the implications of our current knowledge for animals and humans in the modern world. The Company of Biologists Ltd 2016-06-15 /pmc/articles/PMC4920240/ /pubmed/27307539 http://dx.doi.org/10.1242/jeb.132167 Text en © 2016. Published by The Company of Biologists Ltd http://creativecommons.org/licenses/by/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
spellingShingle Review
Brown, Timothy M.
Using light to tell the time of day: sensory coding in the mammalian circadian visual network
title Using light to tell the time of day: sensory coding in the mammalian circadian visual network
title_full Using light to tell the time of day: sensory coding in the mammalian circadian visual network
title_fullStr Using light to tell the time of day: sensory coding in the mammalian circadian visual network
title_full_unstemmed Using light to tell the time of day: sensory coding in the mammalian circadian visual network
title_short Using light to tell the time of day: sensory coding in the mammalian circadian visual network
title_sort using light to tell the time of day: sensory coding in the mammalian circadian visual network
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4920240/
https://www.ncbi.nlm.nih.gov/pubmed/27307539
http://dx.doi.org/10.1242/jeb.132167
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