|   | 
Details
   web
Records
Author (up) Pilorz, V.; Tam, S.K.E.; Hughes, S.; Pothecary, C.A.; Jagannath, A.; Hankins, M.W.; Bannerman, D.M.; Lightman, S.L.; Vyazovskiy, V.V.; Nolan, P.M.; Foster, R.G.; Peirson, S.N.
Title Melanopsin Regulates Both Sleep-Promoting and Arousal-Promoting Responses to Light Type Journal Article
Year 2016 Publication PLoS Biology Abbreviated Journal PLoS Biol
Volume 14 Issue 6 Pages e1002482
Keywords Human health; melanopsin; sleep; circadian rhythm
Abstract Light plays a critical role in the regulation of numerous aspects of physiology and behaviour, including the entrainment of circadian rhythms and the regulation of sleep. These responses involve melanopsin (OPN4)-expressing photosensitive retinal ganglion cells (pRGCs) in addition to rods and cones. Nocturnal light exposure in rodents has been shown to result in rapid sleep induction, in which melanopsin plays a key role. However, studies have also shown that light exposure can result in elevated corticosterone, a response that is not compatible with sleep. To investigate these contradictory findings and to dissect the relative contribution of pRGCs and rods/cones, we assessed the effects of light of different wavelengths on behaviourally defined sleep. Here, we show that blue light (470 nm) causes behavioural arousal, elevating corticosterone and delaying sleep onset. By contrast, green light (530 nm) produces rapid sleep induction. Compared to wildtype mice, these responses are altered in melanopsin-deficient mice (Opn4-/-), resulting in enhanced sleep in response to blue light but delayed sleep induction in response to green or white light. We go on to show that blue light evokes higher Fos induction in the SCN compared to the sleep-promoting ventrolateral preoptic area (VLPO), whereas green light produced greater responses in the VLPO. Collectively, our data demonstrates that nocturnal light exposure can have either an arousal- or sleep-promoting effect, and that these responses are melanopsin-mediated via different neural pathways with different spectral sensitivities. These findings raise important questions relating to how artificial light may alter behaviour in both the work and domestic setting.
Address Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, Oxford Molecular Pathology Institute, Dunn School of Pathology, University of Oxford, Oxford, United Kingdom; stuart.peirson(at)eye.ox.ac.uk (SNP); russell.foster(at)eye.ox.ac.uk (RGF).
Corporate Author Thesis
Publisher PLOS Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1544-9173 ISBN Medium
Area Expedition Conference
Notes PMID:27276063; PMCID:PMC4898879 Approved no
Call Number IDA @ john @ Serial 1490
Permanent link to this record
 

 
Author (up) van Diepen, H.C.; Foster, R.G.; Meijer, J.H.
Title A colourful clock Type Journal Article
Year 2015 Publication PLoS Biology Abbreviated Journal PLoS Biol
Volume 13 Issue 5 Pages e1002160
Keywords Animals; Commentary; *Circadian Rhythm; suprachiasmatic nuclei; melanopsin; retinal ganglion cells; entrainment; photoperiod
Abstract Circadian rhythms are an essential property of life on Earth. In mammals, these rhythms are coordinated by a small set of neurons, located in the suprachiasmatic nuclei (SCN). The environmental light/dark cycle synchronizes (entrains) the SCN via a distinct pathway, originating in a subset of photosensitive retinal ganglion cells (pRGCs) that utilize the photopigment melanopsin (OPN4). The pRGCs are also innervated by rods and cones and, so, are both endogenously and exogenously light sensitive. Accumulating evidence has shown that the circadian system is sensitive to ultraviolet (UV), blue, and green wavelengths of light. However, it was unclear whether colour perception itself can help entrain the SCN. By utilizing both behavioural and electrophysiological recording techniques, Walmsley and colleagues show that multiple photic channels interact and enhance the capacity of the SCN to synchronize to the environmental cycle. Thus, entrainment of the circadian system combines both environmental irradiance and colour information to ensure that internal and external time are appropriately aligned.
Address Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University medical School, Leiden, The Netherlands
Corporate Author Thesis
Publisher PLOS Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1544-9173 ISBN Medium
Area Expedition Conference
Notes PMID:25996907; PMCID:PMC4440787 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 1183
Permanent link to this record
 

 
Author (up) Walmsley, L.; Hanna, L.; Mouland, J.; Martial, F.; West, A.; Smedley, A.R.; Bechtold, D.A.; Webb, A.R.; Lucas, R.J.; Brown, T.M.
Title Colour As a Signal for Entraining the Mammalian Circadian Clock Type Journal Article
Year 2015 Publication PLoS Biology Abbreviated Journal PLoS Biol
Volume 13 Issue 4 Pages e1002127
Keywords Animals; biology; color; circadian disruption; animal models; mouse models; Suprachiasmatic Nucleus; Photoperiod; twilight
Abstract Twilight is characterised by changes in both quantity (“irradiance”) and quality (“colour”) of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blue-yellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision.
Address Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
Corporate Author Thesis
Publisher PLOS Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1544-9173 ISBN Medium
Area Expedition Conference
Notes PMID:25884537 Approved no
Call Number IDA @ john @ Serial 1152
Permanent link to this record