scholarly journals The Lighting Environment, Its Metrology, and Non-visual Responses

2021 ◽  
Vol 12 ◽  
Author(s):  
Luc J. M. Schlangen ◽  
Luke L. A. Price
Keyword(s):  
Spectral Sensitivity ◽  
Ganglion Cells ◽  
Proper Time ◽  
International Workshop ◽  
Spatial Vision ◽  
Well Being ◽  
Position Statement ◽  
Light Sources ◽  
Visual Responses ◽  
Visual Effects

International standard CIE S 026:2018 provides lighting professionals and field researchers in chronobiology with a method to characterize light exposures with respect to non-visual photoreception and responses. This standard defines five spectral sensitivity functions that describe optical radiation for its ability to stimulate each of the five α-opic retinal photoreceptor classes that contribute to the non-visual effects of light in humans via intrinsically-photosensitive retinal ganglion cells (ipRGCs). The CIE also recently published an open-access α-opic toolbox that calculates all the quantities and ratios of the α-opic metrology in the photometric, radiometric and photon systems, based on either a measured (user-defined) spectrum or selected illuminants (A, D65, E, FL11, LED-B3) built into the toolbox. For a wide variety of ecologically-valid conditions, the melanopsin-based photoreception of ipRGCs has been shown to account for the spectral sensitivity of non-visual responses, from shifting the timing of nocturnal sleep and melatonin secretion to regulating steady-state pupil diameter. Recent findings continue to confirm that the photopigment melanopsin also plays a role in visual responses, and that melanopsin-based photoreception may have a significant influence on brightness perception and aspects of spatial vision. Although knowledge concerning the extent to which rods and cones interact with ipRGCs in driving non-visual effects is still growing, a CIE position statement recently used melanopic equivalent daylight (D65) illuminance in preliminary guidance on applying “proper light at the proper time” to manipulate non-visual responses. Further guidance on this approach is awaited from the participants of the 2nd International Workshop on Circadian and Neurophysiological Photometry (in Manchester, August 2019). The new α-opic metrology of CIE S 026 enables traceable measurements and a formal, quantitative specification of personal light exposures, photic interventions and lighting designs. Here, we apply this metrology to everyday light sources including a natural daylight time series, a range of LED lighting products and, using the toobox, to a smartphone display screen. This collection of examples suggests ways in which variations in the melanopic content of light over the day can be adopted in strategies that use light to support human health and well-being.

scholarly journals The lighting environment, its metrology and non-visual responses

2020 ◽  
Author(s):  
Luc Schlangen ◽  
Luke Price
Keyword(s):  
Ganglion Cells ◽  
Proper Time ◽  
International Workshop ◽  
Spatial Vision ◽  
Light Sensitivity ◽  
Position Statement ◽  
Time Of Day ◽  
Light Sources ◽  
Visual Responses ◽  
Sensitivity Functions

A new international standard, CIE S 026:2018, defines spectral sensitivity functions that describe optical radiation for its ability to stimulate each of the five α-opic retinal photoreceptor classes that contribute, to non-visual effects and functions of light in humans via intrinsically-photosensitive retinal ganglion cells (ipRGCs). The CIE recently published an α-opic toolbox that calculates all the quantities and ratios of the α-opic metrology in the photometric, radiometric and photon systems, either based on a measured (user-defined) spectrum or on selected illuminants (A, D65, E, FL11, LED-B3) built into the toolbox. For most practical ecologically-valid applications, the melanopsin-based photoreception of ipRGCs has been shown to account for the light sensitivity of non-visual responses, from shifting the timing of nocturnal melatonin secretion to regulating steady-state pupil diameter. A CIE position statement recently adopted melanopic EDI in preliminary guidance on using the “proper light at the proper time” to manipulate non-visual responses. Further guidance in this field is expected from an upcoming scientific consensus paper by the participants of the 2nd International Workshop on Circadian and Neurophysiological Photometry (in Manchester, August 2019). Recent findings continue to confirm that melanopsin also plays a role in visual responses. For instance, brightness perception and aspects of spatial vision can be modulated significantly by melanopsin-based photoreception.The new α-opic metrology standardised in CIE S 026 enables traceable measurements for a formal, quantitative specification of personal light exposures and lighting designs. Here, we apply this metrology, together with the toolbox, to everyday light sources including a natural daylight time series, a range of LED lighting products and a smartphone display screen. This collection of examples is of interest to both lighting and public health professions, and suggests ways in which modulations in the melanopic content of light across time of day can be adopted within strategies that use light to support human health and wellbeing.

Investigating visual mechanisms underlying scene brightness

2016 ◽  
Vol 49 (1) ◽  
pp. 16-32 ◽  
Author(s):  
UC Besenecker ◽  
JD Bullough
Keyword(s):  
Retinal Ganglion Cells ◽  
Spectral Sensitivity ◽  
Short Wavelength ◽  
Ganglion Cells ◽  
Forced Choice ◽  
Light Sources ◽  
Retinal Ganglion ◽  
Brightness Perception ◽  
Light Levels ◽  
Relative Brightness

Short-wavelength (<500 nm) output of light sources enhances scene brightness perception in the low-to-moderate photopic range. This appears to be partially explained by a contribution from short-wavelength cones. Recent evidence from experiments on humans suggests that intrinsically photosensitive retinal ganglion cells (ipRGCs) containing the photopigment melanopsin might also contribute to spectral sensitivity for scene brightness perception. An experiment was conducted to investigate this possibility at two different light levels, near 10 lx and near 100 lx. Subjects provided forced-choice brightness judgments and relative brightness magnitude judgments when comparing two different amber-coloured stimuli with similar chromaticities. A provisional brightness metric including an ipRGC contribution was able to predict the data with substantially smaller errors than a metric based on cone input only.

scholarly journals Photoreceptive retinal ganglion cells control the information rate of the optic nerve

2018 ◽  
Vol 115 (50) ◽  
pp. E11817-E11826 ◽  
Author(s):  
Nina Milosavljevic ◽  
Riccardo Storchi ◽  
Cyril G. Eleftheriou ◽  
Andrea Colins ◽  
Rasmus S. Petersen ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Retinal Ganglion Cells ◽  
Information Flow ◽  
Information Transfer ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Ambient Light ◽  
Visual Responses ◽  
Light Irradiance ◽  
The Brain

Information transfer in the brain relies upon energetically expensive spiking activity of neurons. Rates of information flow should therefore be carefully optimized, but mechanisms to control this parameter are poorly understood. We address this deficit in the visual system, where ambient light (irradiance) is predictive of the amount of information reaching the eye and ask whether a neural measure of irradiance can therefore be used to proactively control information flow along the optic nerve. We first show that firing rates for the retina’s output neurons [retinal ganglion cells (RGCs)] scale with irradiance and are positively correlated with rates of information and the gain of visual responses. Irradiance modulates firing in the absence of any other visual signal confirming that this is a genuine response to changing ambient light. Irradiance-driven changes in firing are observed across the population of RGCs (including in both ON and OFF units) but are disrupted in mice lacking melanopsin [the photopigment of irradiance-coding intrinsically photosensitive RGCs (ipRGCs)] and can be induced under steady light exposure by chemogenetic activation of ipRGCs. Artificially elevating firing by chemogenetic excitation of ipRGCs is sufficient to increase information flow by increasing the gain of visual responses, indicating that enhanced firing is a cause of increased information transfer at higher irradiance. Our results establish a retinal circuitry driving changes in RGC firing as an active response to alterations in ambient light to adjust the amount of visual information transmitted to the brain.

scholarly journals Inverse oculomotor responses of achiasmatic mice expressing a transfer-defective Vax1 mutant

2020 ◽  
Author(s):  
Kwang Wook Min ◽  
Namsuk Kim ◽  
Jae Hoon Lee ◽  
Younghoon Sung ◽  
Museong Kim ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Optic Chiasm ◽  
Stereoscopic Vision ◽  
Retinal Ganglion ◽  
Visual Responses ◽  
Brain Areas ◽  
Optic Stalk ◽  
Intercellular Transfer ◽  
Oculomotor Responses

ABSTRACTIn animals that exhibit stereoscopic visual responses, the axons of retinal ganglion cells (RGCs) connect to brain areas bilaterally by forming a commissure called the optic chiasm (OC). Ventral anterior homeobox 1 (Vax1) contributes to formation of the OC, acting endogenously in optic pathway cells and exogenously in growing RGC axons. Here, we generated Vax1AA/AA mice expressing the Vax1AA mutant, which is selectively incapable of intercellular transfer. We found that RGC axons cannot take up Vax1AA protein from Vax1AA/AA mouse optic stalk (OS) cells, of which maturation is delayed, and fail to access the midline. Consequently, RGC axons of Vax1AA/AA mice connect exclusively to ipsilateral brain areas, resulting in the loss of stereoscopic vision and the inversed oculomotor responses. Together, our study provides physiological evidence for the necessity of intercellular transfer of Vax1 and the importance of the OC in binocular visual responses.

scholarly journals Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions

2020 ◽  
Vol 35 (4) ◽  
pp. 405-415 ◽  
Author(s):  
Martin Moore-Ede ◽  
Anneke Heitmann ◽  
Rainer Guttkuhn
Keyword(s):  
Spectral Sensitivity ◽  
White Light ◽  
Light Exposure ◽  
Human Subjects ◽  
Light Sources ◽  
Led Light ◽  
Light Spectra ◽  
Timing System ◽  
Circadian Timing System ◽  
Spectral Sensitivity Curve

Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000–0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.

Nonlinear integration of multispectral information: Human colour vision analogues to sensory integration in rattlesnake

2012 ◽  
Vol 25 (0) ◽  
pp. 179
Author(s):  
Vincent A. Billock ◽  
Brian H. Tsou
Keyword(s):  
Spectral Sensitivity ◽  
Information Integration ◽  
Sensory Integration ◽  
Colour Vision ◽  
Neural Model ◽  
Neural Firing ◽  
Visual Responses ◽  
Neural Synchronization ◽  
Synchronization Mechanism ◽  
Integration Problems

Information integration occurs at every sensory scale and although distinctions are made for integration between and within senses, integration at intermediate scales may exploit familiar mechanisms. Here, we explore this idea by applying a sensory integration mechanism to some poorly understood multispectral integration problems in human colour vision. Billock and Tsou (IMRF, 2011) used a binding-like neural synchronization mechanism to model intensity-dependent (inverse) enhancement of visual responses by auditory stimulation in cat. The same model also applies to mutual enhancement of visual and infrared responses in rattlesnake, suggesting that a similar mechanism could model integration of spectral information in human colour vision. For example, chromatic brightness is thought to be a vector-like nonlinear combination of luminance and chromatic channels; its neural correlate is unknown. We model its spectral sensitivity by pairwise excitatory synchronization between luminance (broadband) neurons and cortically rectified L+M- and S+M-L- LGN neurons. Similarly, the yellow lobe of the yellow-blue opponent channel is known to be a nonlinearly enhanced combination of long- and medium-wavelength-sensitive inputs, but no sensible neural model for this interaction has been advanced. We model the spectral sensitivity of ‘yellowness’ using excitatory synchronization between cortically rectified L+M+S- and M+L- LGN units. The inputs for both simulations were macaque neural firing rate data (DeValois et al., 1966). Fascinatingly, in both cases, multispectral integration in human colour vision was well modeled using the rattlesnake/cat neural synchronization equations without any use of fitting parameters. This is the first application of sensory integration concepts to human colour vision transformations.

Mechanisms and Meaning of Devries—Rose Adaptation

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 39-39
Author(s):  
K Donner ◽  
P Fagerholm
Keyword(s):  
Light Adaptation ◽  
Ganglion Cells ◽  
Statistical Significance ◽  
Quantum Fluctuations ◽  
Luminance Level ◽  
Square Root ◽  
Visual Responses ◽  
Neural Noise ◽  
Visual Cells ◽  
Mean Luminance

‘Square-root’ or ‘deVries — Rose’ light adaptation is observed over a substantial luminance range in human foveal vision. The classical interpretation is that a detector (presumably in the brain) discriminates the neural signal evoked by the stimulus from the neural noise evoked by quantum fluctuations. It is known, however, that the retina may adjust its gain in inverse proportion to the square root of mean luminance, as observed eg in cat retinal ganglion cells under scotopic or mesopic adaptation. This kind of gain change is approximated even by the primary visual cells, the rods and cones, in at least some vertebrate species up to luminances producing 103 – 104 photoisomerisations per photoreceptor cell, per second. Is square-root adaptation in fact mainly an expression of an inverse-square-root gain in retinal cells? We investigated the roles of gain and noise in human foveal detection of 0.25 deg incremental spots presented for 50 ms on 5 deg steady backgrounds ranging from −0.25 to 2.35 log td, by measuring effects of pixel noise added to the stimulus and background. The results were consistent with the hypothesis that square-root adaptation mainly reflects gain changes, whereas the signal is detected against a constant level of neural noise. They were not consistent with the idea that signals proportional to stimulus intensity are detected against a noise that increases in proportion to quantum fluctuations. Thus, they do not support a simple interpretation of the deVries — Rose law. Still, an inverse-square-root retinal gain may in an evolutionary sense be seen as an adaptation to quantum fluctuations, in view of its functional consequences: (1) that output noise stays constant, independent of luminance level; (2) that light signals of constant statistical significance are encoded by visual responses of constant size.

scholarly journals Photosensitive Melanopsin-Containing Retinal Ganglion Cells in Health and Disease: Implications for Circadian Rhythms

2019 ◽  
Vol 20 (13) ◽  
pp. 3164 ◽  
Author(s):  
Pedro Lax ◽  
Isabel Ortuño-Lizarán ◽  
Victoria Maneu ◽  
Manuel Vidal-Sanz ◽  
Nicolás Cuenca
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Well Being ◽  
Average Density ◽  
Retinal Ganglion ◽  
Healthy Humans ◽  
Cell Alterations ◽  
Circadian Rhythm Disorders

Melanopsin-containing retinal ganglion cells (mRGCs) represent a third class of retinal photoreceptors involved in regulating the pupillary light reflex and circadian photoentrainment, among other things. The functional integrity of the circadian system and melanopsin cells is an essential component of well-being and health, being both impaired in aging and disease. Here we review evidence of melanopsin-expressing cell alterations in aging and neurodegenerative diseases and their correlation with the development of circadian rhythm disorders. In healthy humans, the average density of melanopsin-positive cells falls after age 70, accompanied by age-dependent atrophy of dendritic arborization. In addition to aging, inner and outer retinal diseases also involve progressive deterioration and loss of mRGCs that positively correlates with progressive alterations in circadian rhythms. Among others, mRGC number and plexus complexity are impaired in Parkinson’s disease patients; changes that may explain sleep and circadian rhythm disorders in this pathology. The key role of mRGCs in circadian photoentrainment and their loss in age and disease endorse the importance of eye care, even if vision is lost, to preserve melanopsin ganglion cells and their essential functions in the maintenance of an adequate quality of life.

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