scholarly journals Circadian Photoentrainment in Mice and Humans

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 180
Author(s):  
Russell G. Foster ◽  
Steven Hughes ◽  
Stuart N. Peirson
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Functional Expression ◽  
Time Of Day ◽  
High Irradiance ◽  
Intermittent Light ◽  
Long Duration ◽  
Light History

Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.

scholarly journals Fundamentals of circadian entrainment by light

2021 ◽  
Vol 53 (5) ◽  
pp. 377-393
Author(s):  
RG Foster
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Evidence Based ◽  
Retinal Ganglion ◽  
Rods And Cones ◽  
Long Duration ◽  
Lighting Systems ◽  
Short Wavelength Light ◽  
Wavelength Light

Light at dawn and dusk is the key signal for the entrainment of the circadian clock. Light at dusk delays the clock. Light at dawn advances the clock. The threshold for human entrainment requires relatively bright light for a long duration, but the precise irradiance/duration relationships for photoentrainment have yet to be fully defined. Photoentrainment is achieved by a network of photosensitive retinal ganglion cells (pRGCs) which utilise the short-wavelength light-sensitive photopigment, melanopsin. Although rods and cones are not required, they do play a role in photoentrainment, by projecting to and modulating the endogenous photosensitivity of the pRGCs, but in a manner that remains poorly understood. It is also important to emphasise that the age and prior light exposure of an individual will modify the efficacy of entrainment stimuli. Because of the complexity of photoreceptor interactions, attempts to develop evidence-based human centric lighting are not straightforward. We need to study how humans respond to dynamic light exposure in the ‘real world’ where light intensity, duration, spectral quality and the time of exposure vary greatly. Defining these parameters will allow the development of electric lighting systems that will enhance human circadian entrainment.

scholarly journals Modulation of recognition memory performance by light requires both melanopsin and classical photoreceptors

2016 ◽  
Vol 283 (1845) ◽  
pp. 20162275 ◽  
Author(s):  
Shu K. E. Tam ◽  
Sibah Hasan ◽  
Steven Hughes ◽  
Mark W. Hankins ◽  
Russell G. Foster ◽  
...  
Keyword(s):  
Object Recognition ◽  
Recognition Memory ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Memory Performance ◽  
Recognition Task ◽  
Bright Light ◽  
Brain Network ◽  
Network Activity ◽  
Effect Of Light

Acute light exposure exerts various effects on physiology and behaviour. Although the effects of light on brain network activity in humans are well demonstrated, the effects of light on cognitive performance are inconclusive, with the size, as well as direction, of the effect depending on the nature of the task. Similarly, in nocturnal rodents, bright light can either facilitate or disrupt performance depending on the type of task employed. Crucially, it is unclear whether the effects of light on behavioural performance are mediated via the classical image-forming rods and cones or the melanopsin-expressing photosensitive retinal ganglion cells. Here, we investigate the modulatory effects of light on memory performance in mice using the spontaneous object recognition task. Importantly, we examine which photoreceptors are required to mediate the effects of light on memory performance. By using a cross-over design, we show that object recognition memory is disrupted when the test phase is conducted under a bright light (350 lux), regardless of the light level in the sample phase (10 or 350 lux), demonstrating that exposure to a bright light at the time of test, rather than at the time of encoding, impairs performance. Strikingly, the modulatory effect of light on memory performance is completely abolished in both melanopsin-deficient and rodless–coneless mice. Our findings provide direct evidence that melanopsin-driven and rod/cone-driven photoresponses are integrated in order to mediate the effect of light on memory performance.

scholarly journals luox: novel open-access and open-source web platform for calculating and sharing physiologically relevant quantities for light and lighting

2021 ◽  
Vol 6 ◽  
pp. 69
Author(s):  
Manuel Spitschan ◽  
James Mead ◽  
Chris Roos ◽  
Chris Lowis ◽  
Ben Griffiths ◽  
...  
Keyword(s):  
Open Access ◽  
Open Source ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Research Area ◽  
Visual Responses ◽  
Highly Active ◽  
Architectural Lighting ◽  
Active Research

Light exposure has a profound impact on human physiology and behaviour. For example, light exposure at the wrong time can disrupt our circadian rhythms and acutely suppress the production of melatonin. In turn, appropriately timed light exposure can support circadian photoentrainment. Beginning with the discovery that melatonin production is acutely suppressed by bright light more than 40 years ago, understanding which aspects of light drive the 'non-visual' responses to light remains a highly active research area, with an important translational dimension and implications for "human-centric" or physiologically inspired architectural lighting design. In 2018, the International Commission on Illumination (CIE) standardised the spectral sensitivities for predicting the non-visual effects of a given spectrum of light with respect to the activation of the five photoreceptor classes in the human retina: the L, M and S cones, the rods, and the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs). Here, we described a novel, lean, user-friendly, open-access and open-source platform for calculating quantities related to light. The platform, called luox, enables researchers and research users in chronobiology, sleep research and adjacent field to turn spectral measurements into reportable quantities. The luox code base, released under the GPL-3.0 License, is modular and therefore extendable to other spectrum-derived quantities.

Effects of Illuminance and Correlated Color Temperature on Daytime Cognitive Performance, Subjective Mood, and Alertness in Healthy Adults

2017 ◽  
Vol 51 (2) ◽  
pp. 199-230 ◽  
Author(s):  
Yingying Zhu ◽  
Minqi Yang ◽  
Ying Yao ◽  
Xiao Xiong ◽  
Xiaoran Li ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
Light Exposure ◽  
Bright Light ◽  
Time Of Day ◽  
Healthy Adults ◽  
Color Temperature ◽  
Future Research ◽  
Long Term Memory ◽  
Indoor Lighting ◽  
The Impact

This study investigated the impact of indoor illuminance and correlated color temperature (CCT) on healthy adults’ cognitive performance, subjective mood, and alertness during daytime office hours and differences in time-of-day effects. A 2(illuminance) × 2(CCT) × 2(morning vs. afternoon) mixed design ( N = 60) was employed. Participants felt less sleepy in the bright light exposure. The low “cool” lighting induced the least positive mood. The effects of illuminance and CCT on subjective feelings were not time-of-day dependent. The results demonstrated the slowest responses in inhibition, working memory, and recognition of facial expression tasks in the low “warm” lighting. The effect on long-term memory was most pronounced under the high “cool” light exposure, but only in the afternoon for recognition of neutral words. The findings suggest that future research on good indoor lighting should consider illuminance levels and CCT as well as other variables to optimize lighting effects during regular daytime hours.

Novel Micro-Photodiodes for Retina Stimulation

2000 ◽  
Vol 609 ◽  
Author(s):  
M. Rojahn ◽  
M.B. Schubert
Keyword(s):  
Amorphous Silicon ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Open Circuit ◽  
In Vitro Tests ◽  
Buffer Solution ◽  
Long Term Stability ◽  
Current Voltage

ABSTRACTWe present a new design of micro-photodiodes for in-vitro tests to electrically stimulate the ganglion cells of chicken and rat retinae upon light exposure of the photodiodes. Based on amorphous silicon, our laterally series connected double-stacked micro-photodiodes provide an open circuit voltage of 2.3 volts. Photolithographic steps as well as etching procedures for patterning the back contact, the amorphous silicon layers and the front contact are described. We analyse current- voltage-measurements performed with direct contact of the metal needles of a micro-positioning system to the device's electrodes. In order to test the performance of an individual micro-photodiode in an electrolyte environment, the stimulation electrode of the device is also contacted with a micro-droplet of buffer solution. Further improvement is needed, mainly addressing the problem of long-term stability of the device in electrolyte environments.

Photoreception

2019 ◽  
pp. 178-216
Author(s):  
Gordon L. Fain
Keyword(s):  
Light Adaptation ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Light Response ◽  
Sensory Transduction ◽  
Individual Treatment ◽  
Rods And Cones ◽  
Response Light

“Photoreception” is the ninth chapter of the book Sensory Transduction and begins with general mechanisms of light detection, photopigment activation, and the variety of pathways of phototransduction using the scallop eye as an example. There is then a thorough treatment of the photoreceptors of arthropods, particularly those of Limulus and Drosophila. Following a description of photoreceptor anatomy, the chapter describes transduction in these arthropods including photoreceptor channels and the role of Ca2+ in the regulation of gain and turnoff. It then proceeds to vertebrate rods and cones, with individual treatment of the topics of transduction in vertebrate photoreceptors, the ion channels of rods and cones, the description and measurement of the photocurrent, pathways responsible for shutting down the light response, light adaptation, pigment renewal, and the recovery of sensitivity after bright light exposure. It concludes with transduction in intrinsically photosensitive retinal ganglion cells.

scholarly journals luox: novel validated open-access and open-source web platform for calculating and sharing physiologically relevant quantities for light and lighting

2021 ◽  
Vol 6 ◽  
pp. 69
Author(s):  
Manuel Spitschan ◽  
James Mead ◽  
Chris Roos ◽  
Chris Lowis ◽  
Ben Griffiths ◽  
...  
Keyword(s):  
Open Access ◽  
Open Source ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Research Area ◽  
Visual Responses ◽  
Highly Active ◽  
Architectural Lighting ◽  
Active Research

Light exposure has a profound impact on human physiology and behaviour. For example, light exposure at the wrong time can disrupt our circadian rhythms and acutely suppress the production of melatonin. In turn, appropriately timed light exposure can support circadian photoentrainment. Beginning with the discovery that melatonin production is acutely suppressed by bright light more than 40 years ago, understanding which aspects of light drive the 'non-visual' responses to light remains a highly active research area, with an important translational dimension and implications for "human-centric" or physiologically inspired architectural lighting design. In 2018, the International Commission on Illumination (CIE) standardised the spectral sensitivities for predicting the non-visual effects of a given spectrum of light with respect to the activation of the five photoreceptor classes in the human retina: the L, M and S cones, the rods, and the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs). Here, we described a novel, lean, user-friendly, open-access and open-source platform for calculating quantities related to light. The platform, called luox, enables researchers and research users in chronobiology, sleep research and adjacent field to turn spectral measurements into reportable quantities. The luox code base, released under the GPL-3.0 License, is modular and therefore extendable to other spectrum-derived quantities. luox has been endorsed by the CIE following black-box validation.

The effects of intermittent light during the evening on sleepiness, sleep electroencephalographic spectral power and performance the next morning

2019 ◽  
Vol 51 (8) ◽  
pp. 1159-1177 ◽  
Author(s):  
MQ Yang ◽  
QW Chen ◽  
YY Zhu ◽  
Q Zhou ◽  
YG Geng ◽  
...  
Keyword(s):  
Cognitive Functioning ◽  
Light Exposure ◽  
Light Condition ◽  
Continuous Light ◽  
Bright Light ◽  
Beta Activity ◽  
Intermittent Light ◽  
Dim Light ◽  
And Performance ◽  
Electroencephalographic Activity

Most studies on the effects of light exposure have been conducted with continuous light. The present study investigated the effects of intermittent light exposure on sleepiness, mood, electroencephalographic activity during sleep and performance the next morning. Fifteen volunteers were scheduled to come to the sleep laboratory to experience different lighting conditions: intermittent bright light, continuous bright light and continuous dim light. Subjective sleepiness and mood were assessed during light exposure, with electroencephalographic recording during sleep. After waking the next morning, participants filled out questionnaires and went through two cognitive tasks. The results revealed significantly lower ratings of sleepiness after intermittent light exposure, which is not different from the ratings in the continuous bright light condition, and an increase in vitality during later part of the evening and more beta activity during the first 90 minutes of sleep in the intermittent light condition, in comparison with the continuous dim light condition. However, both intermittent and continuous bright light exposure showed no difference from the continuous dim light condition in subjects' mood and cognitive functioning the next morning. The data indicated intermittent light during evening decreased sleepiness, had only minimal impact on mood in the evening, increased beta electroencephalographic activity during sleep, but had no significant influence on cognitive functioning the next morning.

scholarly journals Time-of-day-dependent effects of bright light exposure on human psychophysiology: comparison of daytime and nighttime exposure

2006 ◽  
Vol 290 (5) ◽  
pp. R1413-R1420 ◽  
Author(s):  
Melanie Rüger ◽  
Marijke C. M. Gordijn ◽  
Domien G. M. Beersma ◽  
Bonnie de Vries ◽  
Serge Daan
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Light Exposure ◽  
Core Body Temperature ◽  
Bright Light ◽  
Time Of Day ◽  
Wide Field ◽  
Young Males ◽  
Core Body ◽  
Bright Light Exposure

Bright light can influence human psychophysiology instantaneously by inducing endocrine (suppression of melatonin, increasing cortisol levels), other physiological changes (enhancement of core body temperature), and psychological changes (reduction of sleepiness, increase of alertness). Its broad range of action is reflected in the wide field of applications, ranging from optimizing a work environment to treating depressed patients. For optimally applying bright light and understanding its mechanism, it is crucial to know whether its effects depend on the time of day. In this paper, we report the effects of bright light given at two different times of day on psychological and physiological parameters. Twenty-four subjects participated in two experiments ( n = 12 each). All subjects were nonsmoking, healthy young males (18–30 yr). In both experiments, subjects were exposed to either bright light (5,000 lux) or dim light <10 lux (control condition) either between 12:00 P.M. and 4:00 P.M. ( experiment A) or between midnight and 4:00 A.M. ( experiment B). Hourly measurements included salivary cortisol concentrations, electrocardiogram, sleepiness (Karolinska Sleepiness Scale), fatigue, and energy ratings (Visual Analog Scale). Core body temperature was measured continuously throughout the experiments. Bright light had a time-dependent effect on heart rate and core body temperature; i.e., bright light exposure at night, but not in daytime, increased heart rate and enhanced core body temperature. It had no significant effect at all on cortisol. The effect of bright light on the psychological variables was time independent, since nighttime and daytime bright light reduced sleepiness and fatigue significantly and similarly.

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