Non‐Parametric Entrainment by Natural Twilight in the Microchiropteran Bat,<i>Hipposideros Speoris</i>Inside a Cave

Joshi, Dilip S.; Vanlalnghaka, C.

doi:10.1080/07420520500180116

Cited by 10 publications

(5 citation statements)

References 20 publications

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“…Melanopsin-expressing cells in the retina show rhythmic oscillations with a greater expression just before lights-on (González-Menéndez et al, 2009). Second, transitions may be mediated by different photoreceptors, long-wavelength photoreceptors for dusk and short-wavelength photoreceptors for dawn entrainment (Joshi and Vanlalnghaka, 2005). Although lemurs have photoreceptors sensitive to short and long wavelengths (Dkhissi-Benyahya et al, 2001), our results provide no direct support for the second hypothesis since the variation of synchronization with wavelength does not vary for dusk or dawn.…”

Section: Discussioncontrasting

confidence: 58%

Increased Late Night Response to Light Controls the Circadian Pacemaker in a Nocturnal Primate

et al. 2010

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The mammalian endogenous circadian clock, the suprachiasmatic nuclei, receives environmental inputs, namely the light-dark cycle, through photopigments located in the eye and from melanopsin-expressing retinal ganglion cells. The authors investigated the influence of light wavelength and intensity on the synchronization of the rest-activity rhythm of the gray mouse lemur, a nocturnal Malagasy primate. Animals were tested at different irradiance levels (320, 45, 13, and 6 nmol x m(-2) x s(- 1)) under several light wavelengths (from 400 to 610 nm). Several parameters including circadian period, activity, and body temperature waveforms were used to assess synchronization to a 12:12 light-dark cycle in comparison to control treatments (12:12 white light or continuous darkness). Entrainment of the circadian rest-activity cycle increased with light intensity. It was more efficient for mid wavelengths relative to shorter or longer wavelengths but not coincident with melanopsin maximal sensitivity, suggesting other photoreceptors are likely involved in lemurs' photoentrainment. The authors obtained a novel synchronization pattern characterized by a clear synchronization to lights-on only without phasing to lights-off. Changes in photo-responsiveness at dusk and dawn highlight differential responses of evening and morning oscillators in the circadian clock.

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Section: Discussioncontrasting

confidence: 58%

Increased Late Night Response to Light Controls the Circadian Pacemaker in a Nocturnal Primate

et al. 2010

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“…This idea has already been suggested for bats, for which photoentrainment may be mediated by S-cones at dusk and M-cones at dawn (Joshi and Vanlalnghaka, 2005). Identification of the mechanisms at stake requires further investigation: experiments on young adults with greater sample size and fully repeated design, and retinal examination of old adults to track any age-related changes in photoreceptor and RGC populations.…”

Section: Physiological Basis Of Light Photoreceptionmentioning

confidence: 92%

Age Affects Photoentrainment in a Nocturnal Primate

et al. 2012

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The endogenous circadian clock is entrained by external cues, mainly the light-dark cycle received by photopigments located in the retina. The authors investigated (1) the effect of aging on the synchronization of the rest-activity rhythm and (2) the physiological basis of light photoreception in the gray mouse lemur, a nocturnal Malagasy primate. Old individuals were tested at different irradiance levels under 3 different light wavelengths previously shown to trigger maximal response in young adults. Investigators analyzed animal activity and temperature waveforms and used 2 reference treatments, strong white light and continuous darkness. The investigation revealed manifold effects of aging picturing a general loss of responsiveness to light and age-related changes in activity and temperature. In addition, the investigation shows that photoentrainment is a continuous process. Short wavelengths (430 nm) are more efficient than longer wavelengths (470-540 nm) at low light levels at dawn and across all light levels at dusk. This suggests an implication of S-cones, differential at dawn and dusk. This results, surprising for several reasons, calls for further investigation. The study brings an interesting contribution to the understanding of the physiological processes underlying synchronization to light.

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“…Locomotion within the dark cave and under starlight or moonlight condition is presumably mediated strongly by echolocation rather than image-forming vision. The presence of an opponent processing system for photoentrainment in a non-visual animal suggests the evolutionary eminence of such a color coding scheme (Joshi and Vanlalnghaka, 2005). …”

Section: Chromatic Circadian Photosensitivity In Mammalsmentioning

confidence: 99%

Chromatic clocks: Color opponency in non-image-forming visual function

Spitschan

Lucas

Brown

2017

Neuroscience & Biobehavioral Reviews

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During dusk and dawn, the ambient illumination undergoes drastic changes in irradiance (or intensity) and spectrum (or color). While the former is a well-studied factor in synchronizing behavior and physiology to the earth’s 24-h rotation, color sensitivity in the regulation of circadian rhythms has not been systematically studied. Drawing on the concept of color opponency, a well-known property of image-forming vision in many vertebrates (including humans), we consider how the spectral shifts during twilight are encoded by a color-opponent sensory system for non-image-forming (NIF) visual functions, including phase shifting and melatonin suppression. We review electrophysiological evidence for color sensitivity in the pineal/parietal organs of fish, amphibians and reptiles, color coding in neurons in the circadian pacemaker in mice as well as sporadic evidence for color sensitivity in NIF visual functions in birds and mammals. Together, these studies suggest that color opponency may be an important modulator of light-driven physiological and behavioral responses.

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Non‐Parametric Entrainment by Natural Twilight in the Microchiropteran Bat,Hipposideros SpeorisInside a Cave

Cited by 10 publications

References 20 publications

Increased Late Night Response to Light Controls the Circadian Pacemaker in a Nocturnal Primate

Increased Late Night Response to Light Controls the Circadian Pacemaker in a Nocturnal Primate

Age Affects Photoentrainment in a Nocturnal Primate

Chromatic clocks: Color opponency in non-image-forming visual function

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