A5077868107- Circadian rhythm and melatonin
- Photoreceptor and optogenetics research
- Retinal Development and Disorders
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Olfactory and Sensory Function Studies
- melanin and skin pigmentation
- Sleep and Wakefulness Research
- Receptor Mechanisms and Signaling
- Neurobiology and Insect Physiology Research
- Visual perception and processing mechanisms
- Neuropeptides and Animal Physiology
- Neural dynamics and brain function
- Neuroendocrine regulation and behavior
- Impact of Light on Environment and Health
- Obstructive Sleep Apnea Research
- Regulation of Appetite and Obesity
- Renin-Angiotensin System Studies
- Neuroscience of respiration and sleep
- Biochemical Analysis and Sensing Techniques
- Neuroscience and Neural Engineering
- Neuroscience and Neuropharmacology Research
- Advanced Fluorescence Microscopy Techniques
- Wildlife Ecology and Conservation
- Hemoglobin structure and function
University of Manchester
2014-2024
Sorbonne Université
2016-2023
Centre National de la Recherche Scientifique
1996-2023
Institut Parisien de Chimie Moléculaire
2023
Chembio (United States)
2016-2023
Manchester Academic Health Science Centre
2017-2021
University of California, Los Angeles
2020
Universidade Federal do Rio de Janeiro
2020
Faculty (United Kingdom)
2015
University of Leicester
2012
Twilight is characterised by changes in both quantity ("irradiance") and quality ("colour") of light. Animals use the variation irradiance to adjust their internal circadian clocks, aligning behaviour physiology with solar cycle. However, it currently unknown whether colour also contribute this entrainment process. Using environmental measurements, we show here that mammalian blue–yellow discrimination provides a more reliable method tracking twilight progression than simply measuring...
BackgroundIn bright light, mammals use a distinct photopigment (melanopsin) to measure irradiance for centrally mediated responses such as circadian entrainment. We aimed determine whether the information generated by melanopsin is also used visual system signal light adaptation. To this end, we compared retinal and thalamic range of artificial natural stimuli presented using spectral compositions that either approximate mouse's experience daylight ("daylight") or are selectively depleted...
Melanopsin photoreception enhances retinal responses to variations in ambient light (irradiance) and drives non-image-forming visual reflexes such as circadian entrainment [1Schmidt T.M. Chen S.K. Hattar S. Intrinsically photosensitive ganglion cells: many subtypes, diverse functions.Trends Neurosci. 2011; 34: 572-580Abstract Full Text PDF PubMed Scopus (378) Google Scholar, 2Schmidt Do M.T. Dacey D. Lucas R. Matynia A. Melanopsin-positive intrinsically from form function.J. 31:...
Abstract Objectives Artificial light sources such as visual display units (VDUs) elicit a range of subconscious and reflex responses, including increases in alertness suppression pineal melatonin. Such responses employ dedicated retinal circuits encompassing melanopsin photoreceptors. Here, we aimed to determine whether this arrangement can be exploited modulate the impact VDUs on melatonin onset without altering appearance. Methods We generated five-primary VDU capable presenting metameric...
Abstract Detection and discrimination of spatial patterns is thought to originate with photoreception by rods cones. Here, we investigated whether the inner-retinal photoreceptor melanopsin could represent a third origin for form vision. We developed 4-primary visual display capable presenting differing in contrast vs cones, generated spectrally distinct stimuli that were indistinguishable cones (metamers) but presented melanopsin. Healthy observers detect sinusoidal gratings formed these...
Mammalian circadian rhythms are orchestrated by a master pacemaker in the hypothalamic suprachiasmatic nuclei (SCN), which receives information about 24 h light-dark cycle from retina. The accepted function of this light signal is to reset phase order ensure appropriate synchronization with celestial day. Here, we ask whether also impacts another key property oscillation, its amplitude. To end, measured behavioral activity, body temperature, and SCN electrophysiological activity diurnal murid rodent
In humans, short-wavelength light evokes larger circadian responses than longer wavelengths [1Wright H.R. Lack L.C. Effect of wavelength on suppression and phase delay the melatonin rhythm.Chronobiol. Int. 2001; 18: 801-808Crossref PubMed Scopus (162) Google Scholar, 2Wright Kennaway D.J. Differential effects in advancing rhythm.J. Pineal Res. 2004; 36: 140-144Crossref (141) 3Gooley J.J. Rajaratnam S.M. Brainard G.C. Kronauer R.E. Czeisler C.A. Lockley S.W. Spectral human system depend...
Light exposure is a vital regulator of physiology and behaviour in humans. However, monitoring light not included current wearable Internet-of-Things (IoT) devices, only recently have international standards defined α-opic equivalent daylight illuminance measures for how the eye responds to light. This paper reports sensor node that can be incorporated into IoT provide real-world settings. We present system design, electronic performance testing, accuracy measurements when compared...
Significance Irradiance-dependent (“luxotonic”) changes in baseline firing were first described neurones of the early visual system decades ago. However, origin and function (if any) this response is still poorly understood. Here we address both questions by recording electrophysiological activity mouse dorsal lateral geniculate nucleus over a simulated dawn. First, show that photopic regime luxotonic becomes increasingly driven inner-retinal melanopsin photoreceptors as irradiance...
Animal opsins are light-sensitive G-protein-coupled receptors (GPCRs) that enable optogenetic control over the major heterotrimeric G-protein signaling pathways in animal cells. As such, have potential applications both biomedical research and therapy. Selecting opsin with best balance of activity selectivity for a given application requires knowing their ability to couple full range relevant Gα subunits. We present GsX assay, set tools based on chimeric Gs subunits transduce coupling...
Confocal microscopy is routinely used for high-resolution fluorescence imaging of biological specimens. Most standard confocal systems scan a laser across specimen and collect emitted light passing through single pinhole to produce an optical section the sample. Sequential scanning on point-by-point basis limits speed image acquisition even fastest commercial instruments struggle resolve temporal dynamics rapid cellular events such as calcium signals. Various approaches have been introduced...
There is no consensus on the best inhibitory optogenetic tool. Since Gi/o signalling a native mechanism of neuronal inhibition, we asked whether Lamprey Parapinopsin ("Lamplight"), Gi/o-coupled bistable animal opsin, could be used for silencing. We show that short (405 nm) and long (525 wavelength pulses repeatedly switch Lamplight between stable active inactive states, respectively, combining these wavelengths can to achieve intermediate levels activity. These properties applied produce...
Abstract Measuring vision in rodents is a critical step for understanding vision, improving models of human disease, and developing therapies. Established behavioural tests perceptual such as the visual water task, rely on learning. The learning process, while effective sighted animals, can be laborious stressful animals with impaired requiring long periods training. Current that do not require training are based sub-conscious, reflex responses (e.g. optokinetic nystagmus) don’t involvement...
Electrophysiological responses of SCN neurons to light steps are well established, but more natural modulations in irradiance have been much less studied. We address this deficit first by showing that variations for human subjects biased towards low temporal frequencies and small magnitudes. Using extracellular recordings we show the mouse responsive stimuli with these characteristics, tracking sinusoidal best at lower responding abrupt changes over a range commonly encountered contrasts....
Abstract Intrinsically photosensitive retinal ganglion cells convey intrinsic, melanopsin‐based, photoreceptive signals alongside those produced by rods and cones to the suprachiasmatic nucleus (SCN) circadian clock. To date, experimental data suggest that melanopsin plays a more significant role in measuring ambient light intensity than cone photoreception. Such studies have overwhelmingly used diffuse stimuli, whereas world around us varies across space time. Here, we investigated extent...
A key step in understanding animal behaviour relies the ability to quantify poses and movements. Methods track body landmarks 2D have made great progress over last few years but accurate 3D reconstruction of freely moving animals still represents a challenge. To address this challenge here we develop 3D-UPPER algorithm, which is fully automated, requires no priori knowledge properties can also be applied data. We find that reduces by [Formula: see text] fold error mouse during compared with...
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and project to central targets, allowing them contribute both image-forming non-image forming vision. Recent studies have highlighted chemical electrical synapses between ipRGCs neurons of inner retina, suggesting a potential influence from melanopsin-born signal affect visual processing at an early stage pathway. We investigated responses in cell layer (GCL) intact dystrophic mouse retinas using...
A series of manganese(I) tricarbonyl complexes formulated as [Mn(8‐HQ)(CO) 3 Imd] (HQ = hydroxyquinoline and Imd imidazole derivatives) was synthesized fully characterized. These structures could be easily accessed from a common dimeric edifice [Mn 2 (8‐HQ) (CO) 6 ]. The structure this complex has been confirmed by X‐ray diffraction studies. Its reaction with range derivatives (Imd) yielded the monomeric [Mn(8‐hydroxyquinoline)(CO) various functional groups an anchoring point for vector....
Inherited retinal degenerations encompass a wide range of diseases that result in the death rod and cone photoreceptors, eventually leading to irreversible blindness. Low vision survives at early stages degeneration, which point it could rely on residual populations rod/cone photoreceptors as well inner photoreceptor, melanopsin. To date, impact partial degeneration visual responses primary thalamus (dorsal lateral geniculate nucleus, dLGN) remains unknown, does their relative reliance...
As part of our ongoing study the toxicity compounds derived from 1,1‐bis(4‐hydroxyphenyl)‐2‐ferrocenylbut‐1‐ene, we have recently shown that closely analogous [3]ferrocenophane complexes an in vitro level substantially higher than their ferrocene counterparts, particularly case mono‐ and diphenol complexes. In this examined whether presence a dimethylamino chain, to chain hydroxytamoxifen, is capable producing ferrocenophane series same antiestrogenic effect observed for OH‐Tam Fc‐OH‐Tam. To...