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Author 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 (up) LoNNe @ christopher.kyba @ Serial 1183
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Author Kelber, A.; Balkenius, A.; Warrant, E.J.
Title Scotopic colour vision in nocturnal hawkmoths Type Journal Article
Year 2002 Publication Nature Abbreviated Journal Nature
Volume 419 Issue 6910 Pages 922-925
Keywords Animals; Behavior, Animal; Color; Color Perception/*physiology; Conditioning (Psychology)/physiology; Cues; *Darkness; Discrimination Learning/physiology; Humans; Light; Lighting; Moths/*physiology; Photic Stimulation; Photoreceptor Cells, Invertebrate/physiology; Reward; Sensitivity and Specificity; Ultraviolet Rays
Abstract Humans are colour-blind at night, and it has been assumed that this is true of all animals. But colour vision is as useful for discriminating objects at night as it is during the day. Here we show, through behavioural experiments, that the nocturnal hawkmoth Deilephila elpenor uses colour vision to discriminate coloured stimuli at intensities corresponding to dim starlight (0.0001 cd x m(-2)). It can do this even if the illumination colour changes, thereby showing colour constancy-a property of true colour vision systems. In identical conditions humans are completely colour-blind. Our calculations show that the possession of three photoreceptor classes reduces the absolute sensitivity of the eye, which indicates that colour vision has a high ecological relevance in nocturnal moths. In addition, the photoreceptors of a single ommatidium absorb too few photons for reliable discrimination, indicating that spatial and/or temporal summation must occur for colour vision to be possible. Taken together, our results show that colour vision occurs at nocturnal intensities in a biologically relevant context.
Address Department of Cell and Organism Biology, Vision Group, Lund University, Helgonavagen 3, S-22362 Lund, Sweden. almut.kelber@zool.lu.se
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:12410310 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 606
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Author Berson, D.M.; Dunn, F.A.; Takao, M.
Title Phototransduction by retinal ganglion cells that set the circadian clock Type Journal Article
Year 2002 Publication Science (New York, N.Y.) Abbreviated Journal Science
Volume 295 Issue 5557 Pages 1070-1073
Keywords Human Health; Animals; Axons/ultrastructure; *Biological Clocks; *Circadian Rhythm; Dendrites/ultrastructure; Isoquinolines; Kinetics; Light; *Light Signal Transduction; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Retinal Ganglion Cells/chemistry/cytology/*physiology; Rod Opsins/analysis/physiology; Suprachiasmatic Nucleus/cytology/*physiology
Abstract Light synchronizes mammalian circadian rhythms with environmental time by modulating retinal input to the circadian pacemaker-the suprachiasmatic nucleus (SCN) of the hypothalamus. Such photic entrainment requires neither rods nor cones, the only known retinal photoreceptors. Here, we show that retinal ganglion cells innervating the SCN are intrinsically photosensitive. Unlike other ganglion cells, they depolarized in response to light even when all synaptic input from rods and cones was blocked. The sensitivity, spectral tuning, and slow kinetics of this light response matched those of the photic entrainment mechanism, suggesting that these ganglion cells may be the primary photoreceptors for this system.
Address Department of Neuroscience, Brown University, Providence, RI, 02912 USA. David_Berson@brown.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0036-8075 ISBN Medium
Area Expedition Conference
Notes PMID:11834835 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 720
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Author Brainard, G.C.; Sliney, D.; Hanifin, J.P.; Glickman, G.; Byrne, B.; Greeson, J.M.; Jasser, S.; Gerner, E.; Rollag, M.D.
Title Sensitivity of the human circadian system to short-wavelength (420-nm) light Type Journal Article
Year 2008 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms
Volume 23 Issue 5 Pages 379-386
Keywords Human Health; Adult; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Male; Melatonin/metabolism; Models, Biological; Neurosecretory Systems; Photons; Pineal Gland/metabolism; Retinal Ganglion Cells/*metabolism; Vision, Ocular
Abstract The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment melanopsin. Nine action spectrum studies using rodents, monkeys, and humans for these responses indicate peak sensitivities in the blue region of the visible spectrum ranging from 459 to 484 nm, with some disagreement in short-wavelength sensitivity of the spectrum. The aim of this work was to quantify the sensitivity of human volunteers to monochromatic 420-nm light for plasma melatonin suppression. Adult female (n=14) and male (n=12) subjects participated in 2 studies, each employing a within-subjects design. In a fluence-response study, subjects (n=8) were tested with 8 light irradiances at 420 nm ranging over a 4-log unit photon density range of 10(10) to 10(14) photons/cm(2)/sec and 1 dark exposure control night. In the other study, subjects (n=18) completed an experiment comparing melatonin suppression with equal photon doses (1.21 x 10(13) photons/cm(2)/sec) of 420 nm and 460 nm monochromatic light and a dark exposure control night. The first study demonstrated a clear fluence-response relationship between 420-nm light and melatonin suppression (p<0.001) with a half-saturation constant of 2.74 x 10(11) photons/cm(2)/sec. The second study showed that 460-nm light is significantly stronger than 420-nm light for suppressing melatonin (p<0.04). Together, the results clarify the visible short-wavelength sensitivity of the human melatonin suppression action spectrum. This basic physiological finding may be useful for optimizing lighting for therapeutic and other applications.
Address Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA. george.brainard@jefferson.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:18838601 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 724
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Author Cajochen, C.; Munch, M.; Kobialka, S.; Krauchi, K.; Steiner, R.; Oelhafen, P.; Orgul, S.; Wirz-Justice, A.
Title High sensitivity of human melatonin, alertness, thermoregulation, and heart rate to short wavelength light Type Journal Article
Year 2005 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab
Volume 90 Issue 3 Pages 1311-1316
Keywords Human Health; Adult; Body Temperature Regulation/physiology/*radiation effects; Circadian Rhythm/physiology/radiation effects; Color; Heart Rate/physiology/*radiation effects; Humans; *Light; Male; Melatonin/*metabolism; Retinal Cone Photoreceptor Cells/physiology; Sleep Stages/physiology/radiation effects; Wakefulness/physiology/*radiation effects
Abstract Light can elicit acute physiological and alerting responses in humans, the magnitude of which depends on the timing, intensity, and duration of light exposure. Here, we report that the alerting response of light as well as its effects on thermoregulation and heart rate are also wavelength dependent. Exposure to 2 h of monochromatic light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm monochromatic light, concomitant with a significantly greater alerting response and increased core body temperature and heart rate ( approximately 2.8 x 10(13) photons/cm(2)/sec for each light treatment). Light diminished the distal-proximal skin temperature gradient, a measure of the degree of vasoconstriction, independent of wavelength. Nonclassical ocular photoreceptors with peak sensitivity around 460 nm have been found to regulate circadian rhythm function as measured by melatonin suppression and phase shifting. Our findings-that the sensitivity of the human alerting response to light and its thermoregulatory sequelae are blue-shifted relative to the three-cone visual photopic system-indicate an additional role for these novel photoreceptors in modifying human alertness, thermophysiology, and heart rate.
Address Centre for Chronobiology, Psychiatric University Clinic, Wilhelm Kleinstr. 27, CH-4025 Basel, Switzerland. christian.cajochen@pukbasel.ch
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-972X ISBN Medium
Area Expedition Conference
Notes PMID:15585546 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 728
Permanent link to this record