scholarly journals Dissecting and modeling photic and melanopsin effects to predict sleep disturbances induced by irregular light exposure in mice

2021 ◽  
Vol 118 (25) ◽  
pp. e2017364118
Author(s):  
Jeffrey Hubbard ◽  
Mio Kobayashi Frisk ◽  
Elisabeth Ruppert ◽  
Jessica W. Tsai ◽  
Fanny Fuchs ◽  
...  
Keyword(s):  
Sleep Disturbances ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Day Length ◽  
Retinal Ganglion ◽  
Suprachiasmatic Nuclei ◽  
Artificial Lighting ◽  
Direct Light ◽  
Light Effects ◽  
Length Changes

Artificial lighting, day-length changes, shift work, and transmeridian travel all lead to sleep–wake disturbances. The nychthemeral sleep–wake cycle (SWc) is known to be controlled by output from the central circadian clock in the suprachiasmatic nuclei (SCN), which is entrained to the light–dark cycle. Additionally, via intrinsically photosensitive retinal ganglion cells containing the photopigment melanopsin (Opn4), short-term light–dark alternations exert direct and acute influences on sleep and waking. However, the extent to which longer exposures typically experienced across the 24-h day exert such an effect has never been clarified or quantified, as disentangling sustained direct light effects (SDLE) from circadian effects is difficult. Recording sleep in mice lacking a circadian pacemaker, either through transgenesis (Syt10cre/creBmal1fl/-) or SCN lesioning and/or melanopsin-based phototransduction (Opn4−/−), we uncovered, contrary to prevailing assumptions, that the contribution of SDLE is as important as circadian-driven input in determining SWc amplitude. Specifically, SDLE were primarily mediated (>80%) through melanopsin, of which half were then relayed through the SCN, revealing an ancillary purpose for this structure, independent of its clock function in organizing SWc. Based on these findings, we designed a model to estimate the effect of atypical light–dark cycles on SWc. This model predicted SWc amplitude in mice exposed to simulated transequatorial or transmeridian paradigms. Taken together, we demonstrate this SDLE is a crucial mechanism influencing behavior on par with the circadian system. In a broader context, these findings mandate considering SDLE, in addition to circadian drive, for coping with health consequences of atypical light exposure in our society.

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 Connections between intrinsically photosensitive retinal ganglion cells and TBI symptoms

Neurology ◽  
2020 ◽  
Vol 95 (18) ◽  
pp. 826-833
Author(s):  
Jason Elenberger ◽  
Bohan Kim ◽  
Alexander de Castro-Abeger ◽  
Tonia S. Rex
Keyword(s):  
Retinal Ganglion Cells ◽  
Sleep Disturbances ◽  
Sleep Problems ◽  
Ganglion Cells ◽  
Light Sensitivity ◽  
Retinal Ganglion ◽  
Root Cause ◽  
Light Sensing ◽  
Pupillary Constriction ◽  
Anxiety Depression

The majority of patients with traumatic brain injury (TBI) are classified as having a mild TBI. Despite being categorized as mild, these individuals report ongoing and complex symptoms, which negatively affect their ability to complete activities of daily living and overall quality of life. Some of the major symptoms include anxiety, depression, sleep problems, headaches, light sensitivity, and difficulty reading. The root cause for these symptoms is under investigation by many in the field. Of interest, several of these symptoms such as headaches, ocular pain, light sensitivity, and sleep disturbances may overlap and share underlying circuitry influenced by the intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells are light sensing, but non–image forming, and they influence corneal function, pupillary constriction, and circadian rhythm. In this review, we discuss these symptoms and propose a role of the ipRGCs as at least one underlying and unifying cause for such symptoms.

Controlling the number of melanopsin-containing retinal ganglion cells by early light exposure

2013 ◽  
Vol 111 ◽  
pp. 17-26 ◽  
Author(s):  
Jie Hong ◽  
Qiang Zeng ◽  
Huaizhou Wang ◽  
Debbie S. Kuo ◽  
William H. Baldridge ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Retinal Ganglion

scholarly journals High Sensitivity of the Human Circadian Melatonin Rhythm to Resetting by Short Wavelength Light

2003 ◽  
Vol 88 (9) ◽  
pp. 4502-4505 ◽  
Author(s):  
Steven W. Lockley ◽  
George C. Brainard ◽  
Charles A. Czeisler
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Monochromatic Light ◽  
High Sensitivity ◽  
Photon Density ◽  
Retinal Ganglion ◽  
Circadian Pacemaker ◽  
Melatonin Rhythm ◽  
Circadian Phase ◽  
Short Wavelength Light

The endogenous circadian oscillator in mammals, situated in the suprachiasmatic nuclei, receives environmental photic input from specialized subsets of photoreceptive retinal ganglion cells. The human circadian pacemaker is exquisitely sensitive to ocular light exposure, even in some people who are otherwise totally blind. The magnitude of the resetting response to white light depends on the timing, intensity, duration, number and pattern of exposures. We report here that the circadian resetting response in humans, as measured by the pineal melatonin rhythm, is also wavelength dependent. Exposure to 6.5 h of monochromatic light at 460 nm induces a two-fold greater circadian phase delay than 6.5 h of 555 nm monochromatic light of equal photon density. Similarly, 460 nm monochromatic light causes twice the amount of melatonin suppression compared to 555 nm monochromatic light, and is dependent on the duration of exposure in addition to wavelength. These studies demonstrate that the peak of sensitivity of the human circadian pacemaker to light is blue-shifted relative to the three-cone visual photopic system, the sensitivity of which peaks at ∼555 nm. Thus photopic lux, the standard unit of illuminance, is inappropriate when quantifying the photic drive required to reset the human circadian pacemaker.

256 Spectrophotometric Properties of 31 Different Commercially Available Blue Blocking Glasses Under Electric Room Lighting

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A103-A103
Author(s):  
Destiny Rupple ◽  
Brooke Mason ◽  
Andrew Tubbs ◽  
Fabian-Xosé Fernandez ◽  
Michael Grandner
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Visible Spectrum ◽  
Retinal Ganglion ◽  
Fluorescent Lamps ◽  
Wide Range ◽  
Indoor Conditions ◽  
Fluorescent Lighting ◽  
One Way Anova ◽  
Room Lighting

Abstract Introduction Blue blocking glasses are often marketed to promote relaxation, sleep, and circadian health by attenuating melatonin-suppressing light exposure. But these glasses represent a wide range of tint and other lens properties. Further, the utility of these glasses under ecologically valid indoor conditions (where light is typically generated from overhead broadspectrum fluorescent lamps) is still unclear, especially across various products. Methods A calibrated spectroradiometer (Ocean Insight), cosine corrector, optic fiber, and software package were used to measure the absolute irradiance (uW/cm^2/nm) emitted from overhead fluorescent lighting in a closeted dark room. Thirty-one commercially available blue blockers were individually placed between the cosine corrector and the luminaire, at a standardized distance and angle, where intensity was measured and analyzed. Each lens was evaluated individually relative to the light source under identical conditions. Then, lenses were collapsed by type into the following groups: red-tinted lenses (RTL), orange-tinted lenses (OTL), orange-tinted lenses with blue reflectivity (OBL), brown-tinted lenses (BTL), yellow-tinted lenses (YTL), and clear reflective blue lenses (RBL). Results There was significant variation in light-blocking across lens types (one-way ANOVA, p < 0.0001). On average, RTL and BTL restricted 59% of the visible light measured from 380-780nm. OTL blocked 47% of the light in this range, while OBL blocked 29%. Both YTL and RBL blocked 14% of the exposure. When narrowing the range of light to 440-530nm (the part of the spectrum most likely to produce a response from melanopsin-expressing retinal ganglion cells), we estimated the following performance: the RTL and OTL blocked close to 100% of the light, OBL blocked 98%, BTL blocked 80%, YTL blocked 33%, and RBL blocked 15%. These differences were statistically significant (one-way ANOVA, p < 0.0001). Individual lenses performed variably within groups, but these differences were small. Conclusion Focusing on the portion of the visible spectrum most likely to suppress melatonin secretion, RTL and OTL blocked exposure the best, followed by OBL, BTL, YTL, and (lastly) RBL. Support (if any) R01MD011600, R01DA051321

scholarly journals In search of blue-light effects on cognitive control

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hsing-Hao Lee ◽  
Yun-Chen Tu ◽  
Su-Ling Yeh
Keyword(s):  
Cognitive Control ◽  
Retinal Ganglion Cells ◽  
Blue Light ◽  
Stroop Effect ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Highly Sensitive ◽  
Light Effects ◽  
Response Task ◽  
Stimulation Of

AbstractPeople are constantly exposed to blue light while engaging in work. It is thus crucial to understand if vast exposure to blue light influences cognitive control, which is essential for working efficiently. Previous studies proposed that the stimulation of intrinsically photosensitive retinal ganglion cells (ipRGCs), a newly discovered photoreceptor that is highly sensitive to blue light, could modulate non-image forming functions. Despite studies that showed blue light (or ipRGCs) enhances brain activations in regions related to cognitive control, how exposure to blue light changes our cognitive control behaviorally remains elusive. We examined whether blue light influences cognitive control through three behavioral tasks in three studies: the sustained attention to response task (SART), the task-switching paradigm, and the Stroop task. Classic effects of the SART, switch cost, and the Stroop effect were found, but no differences were observed in results of different background lights across the six experiments. Together, we conclude that these domains of cognitive control are not influenced by blue light and ipRGCs, and whether the enhancement of blue light on brain activities extends to the behavioral level should be carefully re-examined.

scholarly journals Melanopsin-dependent direct photic effects are equal to clock-driven effects in shaping the nychthemeral sleep-wake cycle

2020 ◽  
Author(s):  
Jeffrey Hubbard ◽  
Mio Kobayashi Frisk ◽  
Elisabeth Ruppert ◽  
Jessica W. Tsai ◽  
Fanny Fuchs ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Sleep Disorder ◽  
Jet Lag ◽  
Circadian Pacemaker ◽  
Suprachiasmatic Nuclei ◽  
Acute Effects ◽  
Dark Cycle ◽  
Direct Light ◽  
Light Effects

AbstractNychthemeral sleep-wake cycles (SWc) are known to be generated by the circadian clock in suprachiasmatic nuclei (SCN), entrained to the light-dark cycle. Light also exerts direct acute effects on sleep and waking. However, under longer photic exposure such as the 24-hour day, the precise significance of sustained direct light effects (SDLE) and circuitry involved have been neither clarified nor quantified, as disentangling them from circadian influence is difficult. Recording sleep in mice lacking a circadian pacemaker and/or melanopsin-based phototransduction, we uncovered, contrary to prevailing assumptions, that circadian-driven input shapes only half of SWc, with SDLE being equally important. SDLE were primarily mediated (>80%) through melanopsin, of which half were relayed through SCN, independent of clock function. These findings were used for a model that predicted SWc under simulated jet-lag, and revealed SDLE as a crucial mechanism influencing behavior, and should be considered for circadian/sleep disorder management and societal lighting optimization.

Jet Lag Recovery and Memory Functions Are Correlated with Direct Light Effects on Locomotion

2020 ◽  
Vol 35 (6) ◽  
pp. 588-597
Author(s):  
Melissa E. S. Richardson ◽  
Samuel Parkins ◽  
Isabelle Kaneza ◽  
Amy-Claire Dauphin
Keyword(s):  
Light Exposure ◽  
Memory Performance ◽  
Memory Loss ◽  
Phase Shifting ◽  
Jet Lag ◽  
Memory Enhancement ◽  
Memory Functions ◽  
Biologically Relevant ◽  
Direct Light ◽  
Light Effects

Jet lag is a circadian disruption that affects millions of people, resulting, among other things, in extreme sleepiness and memory loss. The hazardous implications of such effects are evident in situations in which focus and attention are required. Remarkably, there is a limited understanding of how jet lag recovery and associated memory loss vary year round under different photoperiods. Here we show, using different cycles representing winter, summer, and equinox in male mice, that jet lag recovery and memory vary significantly with photoperiod changes. We uncover a positive correlation of acute light effects on circadian-driven locomotion (known as negative masking) with photoentrainment speed and memory enhancement during jet lag. Specifically, we show that enhancing or reducing negative masking is correlated with better or worse memory performance, respectively. This study indicates that in addition to timed-light exposure for phase shifting, the negative masking response could also be biologically relevant when designing effective treatments of jet lag.

scholarly journals Light-dependent pathways for dopaminergic amacrine cell development and function

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Teona Munteanu ◽  
Katelyn J Noronha ◽  
Amanda C Leung ◽  
Simon Pan ◽  
Jasmine A Lucas ◽  
...  
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Sole Source ◽  
Inner Plexiform Layer ◽  
Retinal Ganglion ◽  
High Acuity ◽  
And Function ◽  
Prime Target

Retinal dopamine is a critical modulator of high acuity, light-adapted vision and photoreceptor coupling in the retina. Dopaminergic amacrine cells (DACs) serve as the sole source of retinal dopamine, and dopamine release in the retina follows a circadian rhythm and is modulated by light exposure. However, the retinal circuits through which light influences the development and function of DACs are still unknown. Intrinsically photosensitive retinal ganglion cells (ipRGCs) have emerged as a prime target for influencing retinal dopamine levels because they costratify with DACs in the inner plexiform layer and signal to them in a retrograde manner. Surprisingly, using genetic mouse models lacking specific phototransduction pathways, we find that while light influences the total number of DACs and retinal dopamine levels, this effect does not require ipRGCs. Instead, we find that the rod pathway is a critical modulator of both DAC number and retinal dopamine levels.

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