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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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Formato: | Online Artículo Texto |
Lenguaje: | English |
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The Company of Biologists Ltd
2016
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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. |
collection | PubMed |
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. |
format | Online Article Text |
id | pubmed-4920240 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | The Company of Biologists Ltd |
record_format | MEDLINE/PubMed |
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 |
work_keys_str_mv | AT browntimothym usinglighttotellthetimeofdaysensorycodinginthemammaliancircadianvisualnetwork |