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https://www.readbyqxmd.com/read/28730123/iprgcs-possible-causation-accounts-for-the-higher-prevalence-of-sleep-disorders-in-glaucoma-patients
#1
Zhen-Zhen Guo, Shan-Ming Jiang, Li-Ping Zeng, Li Tang, Ni Li, Zhu-Ping Xu, Xin Wei
Sleep accounts for a third of one's lifetime, partial or complete deprivation of sleep could elicit sever disorders of body function. Previous studies have reported the higher prevalence of sleep disorders in glaucoma patients, but the definite mechanism for this phenomenon is unknown. On the other hand, it is well known by us that the intrinsically photosensitive retinal ganglion cells (ipRGCs) serve additional ocular functions, called non-image-forming (NIF) functions, in the regulation of circadian rhythm, melatonin secretion, sleep, mood and others...
2017: International Journal of Ophthalmology
https://www.readbyqxmd.com/read/28716667/pupillometric-evaluation-of-the-melanopsin-containing-retinal-ganglion-cells-in-mitochondrial-and-non-mitochondrial-optic-neuropathies
#2
Shakoor Ba-Ali, Henrik Lund-Andersen
In recent years, chromatic pupillometry is used in humans to evaluate the activity of melanopsin expressing intrinsic photosensitive retinal ganglion cells (ipRGCs). Blue light is used to stimulate the ipRGCs and red light activates the rod/cone photoreceptors. The late re-dilation phase of pupillary light reflex is primarily driven by the ipRGCs. Optic neuropathies i.e. Leber hereditary optic neuropathy (LHON), autosomal dominant optic atrophy (ADOA), nonarteritic anterior ischemic optic neuropathy (NAION), glaucoma, optic neuritis and idiopathic intracranial hypertension (IIH) are among the diseases, which have been subject to pupillometric studies...
July 14, 2017: Mitochondrion
https://www.readbyqxmd.com/read/28708670/color-pupillography-in-dorsal-midbrain-syndrome
#3
Carina B Kelbsch, Fumiatsu Maeda, Torsten Strasser, Tobias M Peters, Barbara J C Wilhelm, Helmut M Wilhelm
OBJECTIVE: The purpose of this study was to evaluate the pupil response to chromatic stimuli in patients with lesions in the dorsal midbrain and possibly gain new insights into the afferent pupillary pathways. METHODS: Color pupillography was performed in 5 patients with dorsal midbrain syndrome (DMS), and their results were compared with those of 20 healthy control subjects. We used full-field red stimuli (605 nm) that primarily address the rod/cone system and blue stimuli (420 nm) that preferentially activate intrinsically photosensitive retinal ganglion cells (ipRGCs) directly, with a duration of 4 seconds and a stimulus intensity of 28 lx corneal illumination under mesopic conditions...
September 2017: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
https://www.readbyqxmd.com/read/28688906/effects-of-photopic-and-cirtopic-illumination-on-steady-state-pupil-sizes
#4
Feng Rao, A H S Chan, Xi-Fang Zhu
The conventional view was that cones are responsible for pupil constriction in photopic lighting conditions. With the discovery of intrinsically photosensitive retinal ganglion cells (ipRGC), it was found that signals from ipRGCs along with cones mediated the pupil light reflex in photopic lighting conditions. Although both signals contributed, it was unclear how these signals were summed. In the work reported here, steady-state pupil size was measured with an infrared camera under LED lighting conditions with different color temperatures and luminance...
July 11, 2017: Vision Research
https://www.readbyqxmd.com/read/28687871/chromatic-pupillography-in-hemianopia-patients-with-homonymous-visual-field-defects
#5
Fumiatsu Maeda, Carina Kelbsch, Torsten Straßer, Karolína Skorkovská, Tobias Peters, Barbara Wilhelm, Helmut Wilhelm
PURPOSE: The pupil light reflex is considered to be a simple subcortical reflex. However, many studies have proven that patients with isolated occipital lesions with homonymous hemianopia show pupillary hemihypokinesia. Our hypothesis is that the afferent pupillary system consists of two pathways: one via intrinsically photosensitive retinal ganglion cells (ipRGCs), the other running through the normal RGCs via the visual cortex. The purpose of this study was to test the hypothesis of these two separate pupillomotor pathways...
June 30, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28656675/attenuation-of-short-wavelengths-alters-sleep-and-the-iprgc-pupil-response
#6
Lisa A Ostrin, Kaleb S Abbott, Hope M Queener
PURPOSE: Exposure to increasing amounts of artificial light during the night may contribute to the high prevalence of reported sleep dysfunction. Release of the sleep hormone melatonin is mediated by the intrinsically photosensitive retinal ganglion cells (ipRGCs). This study sought to investigate whether melatonin level and sleep quality can be modulated by decreasing night-time input to the ipRGCs. METHODS: Subjects (ages 17-42, n = 21) wore short wavelength-blocking glasses prior to bedtime for 2 weeks...
July 2017: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
https://www.readbyqxmd.com/read/28649427/global-rise-of-potential-health-hazards-caused-by-blue-light-induced-circadian-disruption-in-modern-aging-societies
#7
REVIEW
Megumi Hatori, Claude Gronfier, Russell N Van Gelder, Paul S Bernstein, Josep Carreras, Satchidananda Panda, Frederick Marks, David Sliney, Charles E Hunt, Tsuyoshi Hirota, Toshiharu Furukawa, Kazuo Tsubota
Mammals receive light information through the eyes, which perform two major functions: image forming vision to see objects and non-image forming adaptation of physiology and behavior to light. Cone and rod photoreceptors form images and send the information via retinal ganglion cells to the brain for image reconstruction. In contrast, nonimage-forming photoresponses vary widely from adjustment of pupil diameter to adaptation of the circadian clock. nonimage-forming responses are mediated by retinal ganglion cells expressing the photopigment melanopsin...
2017: NPJ Aging and Mechanisms of Disease
https://www.readbyqxmd.com/read/28629848/a-novel-intrinsic-electroretinogram-response-in-isolated-mouse-retina
#8
Motoharu Takao, Yumi Fukuda, Takeshi Morita
Since the discovery of intrinsic photosensitive retinal ganglion cell (ipRGC) was reported in 2002, many features specific to this cell type have been described. However, scare information is available on the retinographic components directly reflecting ipRGC activity. In this study, we identified the electroretinogram (microERG) that reflects the photoresponses by ipRGCs in ex vivo preparations of the mouse retina, in which classical photoreceptors (cones and rods) were ablated mechanically and photochemically...
June 17, 2017: Neuroscience
https://www.readbyqxmd.com/read/28617242/a-subset-of-iprgcs-regulates-both-maturation-of-the-circadian-clock-and-segregation-of-retinogeniculate-projections-in-mice
#9
Kylie S Chew, Jordan M Renna, David S McNeill, Diego C Fernandez, William T Keenan, Michael B Thomsen, Jennifer L Ecker, Gideon S Loevinsohn, Cassandra VanDunk, Daniel C Vicarel, Adele Tufford, Shijun Weng, Paul A Gray, Michel Cayouette, Erik D Herzog, Haiqing Zhao, David M Berson, Samer Hattar
The visual system consists of two major subsystems, image-forming circuits that drive conscious vision and non-image-forming circuits for behaviors such as circadian photoentrainment. While historically considered non-overlapping, recent evidence has uncovered crosstalk between these subsystems. Here, we investigated shared developmental mechanisms. We revealed an unprecedented role for light in the maturation of the circadian clock and discovered that intrinsically photosensitive retinal ganglion cells (ipRGCs) are critical for this refinement process...
June 15, 2017: ELife
https://www.readbyqxmd.com/read/28578927/synergistic-signaling-by-light-and-acetylcholine-in-mouse-iris-sphincter-muscle
#10
Qian Wang, Wendy Wing Sze Yue, Zheng Jiang, Tian Xue, Shin H Kang, Dwight E Bergles, Katsuhiko Mikoshiba, Stefan Offermanns, King-Wai Yau
The mammalian pupillary light reflex (PLR) involves a bilateral brain circuit whereby afferent light signals in the optic nerve ultimately drive iris-sphincter-muscle contraction via excitatory cholinergic parasympathetic innervation [1, 2]. Additionally, the PLR in nocturnal and crepuscular sub-primate mammals has a "local" component in the isolated sphincter muscle [3-5], as in amphibians, fish, and bird [6-10]. In mouse, this local PLR requires the pigment melanopsin [5], originally found in intrinsically photosensitive retinal ganglion cells (ipRGCs) [11-19]...
June 19, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28535270/intrinsically-photosensitive-retinal-ganglion-cell-function-sleep-efficiency-and-depression-in-advanced-age-related-macular-degeneration
#11
Michelle L Maynard, Andrew Zele, Anthony Kwan, Beatrix Feigl
Purpose: Melanopsin expressing intrinsically photosensitive retinal ganglion cells (ipRGC) input to multiple brain regions including those for pupil control, circadian rhythms, sleep and mood regulation. Here we measured ipRGC function and its relationship to sleep quality and depression in patients with advanced AMD. Methods: The melanopsin-mediated post-illumination pupil response (PIPR) was measured in 53 patients with advanced AMD (age 78.8 ± 8.8 years) and in 20 healthy controls (age 72...
February 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28532353/ocular-photoreception-for-circadian-rhythm-entrainment-in-mammals
#12
Russell N Van Gelder, Ethan D Buhr
Circadian rhythms are self-sustained, approximately 24-h rhythms of physiology and behavior. These rhythms are entrained to an exactly 24-h period by the daily light-dark cycle. Remarkably, mice lacking all rod and cone photoreceptors still demonstrate photic entrainment, an effect mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells utilize melanopsin (OPN4) as their photopigment. Distinct from the ciliary rod and cone opsins, melanopsin appears to function as a stable photopigment utilizing sequential photon absorption for its photocycle; this photocycle, in turn, confers properties on ipRGCs such as sustained signaling and resistance from photic bleaching critical for an irradiance detection system...
October 14, 2016: Annual Review of Vision Science
https://www.readbyqxmd.com/read/28525301/mood-the-circadian-system-and-melanopsin-retinal-ganglion-cells
#13
Lorenzo Lazzerini Ospri, Glen Prusky, Samer Hattar
The discovery of a third type of photoreceptors in the mammalian retina, intrinsically photosensitive retinal ganglion cells (ipRGCs), has had a revolutionary impact on chronobiology. We can now properly account for numerous non-vision-related functions of light, including its effect on the circadian system. Here, we give an overview of ipRGCs and their function as it relates specifically to mood and biological rhythms. Although circadian disruptions have been traditionally hypothesized to be the mediators of light's effects on mood, here we present an alternative model that dispenses with assumptions of causality between the two phenomena and explains mood regulation by light via another ipRGC-dependent mechanism...
July 25, 2017: Annual Review of Neuroscience
https://www.readbyqxmd.com/read/28466070/a-cre-mouse-line-for-probing-irradiance-and-direction-encoding-retinal-networks
#14
Shai Sabbah, Daniel Berg, Carin Papendorp, Kevin L Briggman, David M Berson
Cell type-specific Cre driver lines have revolutionized the analysis of retinal cell types and circuits. We show that the transgenic mouse Rbp4-Cre selectively labels several retinal neuronal types relevant to the encoding of absolute light intensity (irradiance) and visual motion. In the ganglion cell layer (GCL), most marked cells are wide-field spiking polyaxonal amacrine cells (ACs) with sustained irradiance-encoding ON responses that persist during chemical synaptic blockade. Their arbors spread about 1 mm across the retina and are restricted to the inner half of the ON sublamina of the inner plexiform layer (IPL)...
March 2017: ENeuro
https://www.readbyqxmd.com/read/28421205/the-preferential-impairment-of-pupil-constriction-stimulated-by-blue-light-in-patients-with-type-2-diabetes-without-autonomic-neuropathy
#15
Fukashi Ishibashi, Rie Kojima, Miki Taniguchi, Aiko Kosaka, Harumi Uetake, Mitra Tavakoli
The main aim of the present paper is to examine whether the pupillary light reflex (PLR) mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs) is impaired in type 2 diabetic patients. One hundred and three diabetic patients without diabetic autonomic neuropathy (DAN) and 42 age-matched controls underwent a series of detailed neurological examinations. The patients were stratified into three groups: stage I, no neuropathy; stage II, asymptomatic neuropathy; stage III, symptomatic but without DAN...
2017: Journal of Diabetes Research
https://www.readbyqxmd.com/read/28236851/infant-acetylcholine-dopamine-and-melatonin-dysregulation-neonatal-biomarkers-and-causal-factors-for-asd-and-adhd-phenotypes
#16
Kahl Hellmer, Pär Nyström
Autism spectrum disorders (ASD) and ADHD are common neurodevelopmental disorders that benefit from early intervention but currently suffer from late detection and diagnosis: neurochemical dysregulations are extant already at birth but clinical phenotypes are not distinguishable until preschool age or later. The vast heterogeneity between subjects' phenotypes relates to interaction between multiple unknown factors, making research on factor causality insurmountable. To unlock this situation we pose the hypothesis that atypical pupillary light responses from rods, cones, and the recently discovered ipRGC system reflect early acetylcholine, melatonin, and dopamine dysregulation that are sufficient but not necessary factors for developing ASD and/or ADHD disorders...
March 2017: Medical Hypotheses
https://www.readbyqxmd.com/read/28223508/c-terminal-phosphorylation-regulates-the-kinetics-of-a-subset-of-melanopsin-mediated-behaviors-in-mice
#17
Preethi Somasundaram, Glenn R Wyrick, Diego Carlos Fernandez, Alireza Ghahari, Cindy M Pinhal, Melissa Simmonds Richardson, Alan C Rupp, Lihong Cui, Zhijian Wu, R Lane Brown, Tudor Constantin Badea, Samer Hattar, Phyllis R Robinson
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and mediate several non-image-forming visual functions, including circadian photoentrainment and the pupillary light reflex (PLR). ipRGCs act as autonomous photoreceptors via the intrinsic melanopsin-based phototransduction pathway and as a relay for rod/cone input via synaptically driven responses. Under low light intensities, where only synaptically driven rod/cone input activates ipRGCs, the duration of the ipRGC response will be determined by the termination kinetics of the rod/cone circuits...
March 7, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28160289/melanopsin-expressing-human-retinal-ganglion-cells-subtypes-distribution-and-intraretinal-connectivity
#18
Jens Hannibal, Anders Tolstrup Christiansen, Steffen Heegaard, Jan Fahrenkrug, Jens Folke Kiilgaard
Intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin belong to a heterogenic population of RGCs which regulate the circadian clock, masking behavior, melatonin suppression, the pupillary light reflex, and sleep/wake cycles. The different functions seem to be associated to different subtypes of melanopsin cells. In rodents, subtype classification has associated subtypes to function. In primate and human retina such classification has so far, not been applied. In the present study using antibodies against N- and C-terminal parts of human melanopsin, confocal microscopy and 3D reconstruction of melanopsin immunoreactive (-ir) RGCs, we applied the criteria used in mouse on human melanopsin-ir RGCs...
June 1, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28153865/mechanisms-creating-transient-and-sustained-photoresponses-in-mammalian-retinal-ganglion-cells
#19
Xiwu Zhao, Aaron N Reifler, Melanie M Schroeder, Elizabeth R Jaeckel, Andrew P Chervenak, Kwoon Y Wong
Retinal neurons use sustained and transient light responses to encode visual stimuli of different frequency ranges, but the underlying mechanisms remain poorly understood. In particular, although earlier studies in retinal ganglion cells (RGCs) proposed seven potential mechanisms, all seven have since been disputed, and it remains unknown whether different RGC types use different mechanisms or how many mechanisms are used by each type. Here, we conduct a comprehensive survey in mice and rats of 12 candidate mechanisms that could conceivably produce tonic rod/cone-driven ON responses in intrinsically photosensitive RGCs (ipRGCs) and transient ON responses in three types of direction-selective RGCs (TRHR+, Hoxd10+ ON, and Hoxd10+ ON-OFF cells)...
March 6, 2017: Journal of General Physiology
https://www.readbyqxmd.com/read/28119450/ectopic-expression-of-mouse-melanopsin-in-drosophila-photoreceptors-reveals-fast-response-kinetics-and-persistent-dark-excitation
#20
Bushra Yasin, Elkana Kohn, Maximilian Peters, Rachel Zaguri, Shirley Weiss, Krystina Schopf, Ben Katz, Armin Huber, Baruch Minke
The intrinsically photosensitive M1 retinal ganglion cells (ipRGC) initiate non-image-forming light-dependent activities and express the melanopsin (OPN4) photopigment. Several features of ipRGC photosensitivity are characteristic of fly photoreceptors. However, the light response kinetics of ipRGC is much slower due to unknown reasons. Here we used transgenic Drosophila, in which the mouse OPN4 replaced the native Rh1 photopigment of Drosophila R1-6 photoreceptors, resulting in deformed rhabdomeric structure...
March 3, 2017: Journal of Biological Chemistry
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