ORCID Profile
0000-0002-8572-9268
Current Organisations
Max Planck Institute for Biological Cybernetics
,
Technical University of Munich
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Publisher: Cold Spring Harbor Laboratory
Date: 17-10-2023
Publisher: SAGE Publications
Date: 10-2023
Publisher: Informa UK Limited
Date: 14-03-2022
DOI: 10.1080/17437199.2022.2046482
Abstract: In this White Paper, we outline recommendations from the perspective of health psychology and behavioural science, addressing three research gaps: (1) What methods in the health psychology research toolkit can be best used for developing and evaluating digital health tools? (2) What are the most feasible strategies to reuse digital health tools across populations and settings? (3) What are the main advantages and challenges of sharing (openly publishing) data, code, intervention content and design features of digital health tools? We provide actionable suggestions for researchers joining the continuously growing Open Digital Health movement, poised to revolutionise health psychology research and practice in the coming years. This White Paper is positioned in the current context of the COVID-19 pandemic, exploring how digital health tools have rapidly gained popularity in 2020-2022, when world-wide health promotion and treatment efforts rapidly shifted from face-to-face to remote delivery. This statement is written by the Directors of the not-for-profit Open Digital Health initiative (n = 6), Experts attending the European Health Psychology Society Synergy Expert Meeting (n = 17), and the initiative consultant, following a two-day meeting (19-20th August 2021).
Publisher: Cold Spring Harbor Laboratory
Date: 21-03-2023
DOI: 10.1101/2023.03.17.532785
Abstract: Beyond vision, light has wide-reaching effects on human health and well-being. However, there is no consensus on reporting light characteristics in studies investigating non-visual responses to light. This project aimed at developing a reporting checklist for laboratory-based investigations on the impact of light on non-visual physiology. To this end, a four-step modified Delphi process (three questionnaire-based feedback rounds and one face-to-face group discussion) involving international experts was conducted. Across these four rounds, an initial list of 61 items related to reporting light-based interventions was condensed to a final checklist containing 25 items, based upon consensus among experts (final n=60). Nine of these items were determined to be necessary to report regardless of the specific research question or context. A description of each item was provided in the accompanying guidelines. Most participants (92%) reported being satisfied or very satisfied with the consensus process, checklist, and guidelines. The ENLIGHT Checklist and Guidelines are the first consensus-based guidelines for documenting and reporting ocular light-based interventions for human studies. The implementation of the checklist and guidelines will enhance the impact of light-based research by ensuring comprehensive documentation and reproducibility and enabling data aggregation across studies.
Publisher: Cold Spring Harbor Laboratory
Date: 02-2023
DOI: 10.1101/2023.01.30.526303
Abstract: In humans, the nocturnal secretion of melatonin by the pineal gland is suppressed by ocular exposure to light. In the laboratory, melatonin suppression is a convenient biomarker for this neural pathway. Recent work has found that in iduals differ substantially in their melatonin-suppressive response to light, with the most sensitive in iduals being up to 60 times more sensitive than the least sensitive in iduals. Planning experiments with melatonin suppression as an outcome needs to incorporate these in idual differences, particularly in common resource-limited scenarios where running within-subjects studies at multiple light levels is expensive and not feasible with respect to participant compliance. Here, we present a novel framework for virtual laboratory melatonin suppression experiments, incorporating a Bayesian statistical model. We provide a Shiny web app for power analyses that allows users to modify various experimental parameters (s le size, in idual-level heterogeneity, statistical significance threshold, light levels), and simulate a systematic shift in sensitivity (e.g., due to a pharmacological or other intervention). Our framework helps experimenters to design compelling and robust studies, offering novel insights into the underlying biological variability relevant for practical applications.
Publisher: Cold Spring Harbor Laboratory
Date: 15-09-2019
DOI: 10.1101/763359
Abstract: Exposure to even moderately bright, short-wavelength light in the evening can strongly suppress the production of melatonin and can delay our circadian rhythm. These effects are mediated by the retinohypothalamic pathway, connecting a subset of retinal ganglion cells to the circadian pacemaker in the suprachiasmatic nucleus (SCN) in the brain. These retinal ganglion cells directly express the photosensitive protein melanopsin, rendering them intrinsically photosensitive (ipRGCs). But ipRGCs also receive input from the classical photoreceptors — the cones and rods. Here, we examined whether the short-wavelength-sensitive (S) cones contribute to circadian photoreception by using lights which differed exclusively in the amount of S cone excitation by almost two orders of magnitude (ratio 1:83), but not in the excitation of long-wavelength-sensitive (L) and medium-wavelength-sensitive (M) cones, rods, and melanopsin. We find no evidence for a role of S cones in the acute alerting and melatonin supressing response to evening light exposure, pointing to an exclusive role of melanopsin in driving circadian responses.
Publisher: MDPI AG
Date: 22-12-2019
DOI: 10.20944/PREPRINTS201912.0291.V1
Abstract: The night has historically been neglected in both disciplinary and interdisciplinary research. To some extent, this is not surprising, given the diurnal bias of human researchers, and the difficulty of performing work at night. The night is, however, a critical element of biological, chemical, physical, and social systems on Earth. Moreover, research into social issues such as inequality, demographic changes, and the transition to a sustainable economy will be compromised if night is not considered. Recent years, however, have seen a surge in research into the night. We argue that & night studies& is on the cusp of coming into its own as an interdisciplinary field, and when it does, the field will consider questions that disciplinary researchers haven& rsquo t yet thought to ask.
Publisher: MDPI AG
Date: 10-01-2020
DOI: 10.3390/J3010001
Abstract: The night has historically been neglected in both disciplinary and interdisciplinary research. To some extent, this is not surprising, given the diurnal bias of human researchers and the difficulty of performing work at night. The night is, however, a critical element of biological, chemical, physical, and social systems on Earth. Moreover, research into social issues such as inequality, demographic changes, and the transition to a sustainable economy will be compromised if the night is not considered. Recent years, however, have seen a surge in research into the night. We argue that “night studies” is on the cusp of coming into its own as an interdisciplinary field, and that when it does, the field will consider questions that disciplinary researchers have not yet thought to ask.
Publisher: The Royal Society
Date: 09-03-2022
Abstract: The melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) are characterized by a delayed off-time following the cessation of light stimulation. Here, we exploited this unusual physiologic property to characterize the exquisite sensitivity of the human circadian system to flashed light. In a 34 h in-laboratory between-subjects design, we examined phase shifting in response to variable-intensity (3–9500 photopic lux) flashes at fixed duration (2 ms n = 28 participants) and variable-duration (10 µs–10 s) flashes at fixed intensity (2000 photopic lux n = 31 participants). Acute melatonin suppression, objective alertness and subjective sleepiness during the flash sequence were also assessed. We find a dose–response relationship between flash intensity and circadian phase shift, with an indication of a possible threshold-like behaviour. We find a slight parametric relationship between flash duration and circadian phase shift. Consistent with prior studies, we observe no dose–response relationship to either flash intensity or duration and the acute impact of light on melatonin suppression, objective alertness or subjective sleepiness. Our findings are consistent with circadian responses to a sequence of flashes being mediated by rod or cone photoreceptors via ipRGC integration.
Publisher: Cold Spring Harbor Laboratory
Date: 04-04-2019
DOI: 10.1101/596957
Abstract: Optical filters and tints manipulating short-wavelength light (so-called “blue-blocking” or “blue-attenuating”) are used as a remedy for a range of ocular, retinal, neurological and psychiatric disorders. In many cases, the only available quantification of the optical effects of a given optical filter is the spectral transmittance, which specifies the amount of light transmitted as a function of wavelength. Here, we propose a novel physiologically relevant and retinally referenced framework for quantifying the visual and non-visual effects of these filters, incorporating the attenuation of luminance (luminance factor), the attenuation of melanopsin activation (melanopsin factor), the shift in colour, and the reduction of the colour gamut (gamut factor). We examined a novel data base of optical transmittance filters (n=120) which were digitally extracted from a variety of sources and find a large ersity in the alteration of visual and non-visual properties. We suggest that future studies and examinations of the physiological effects of optical filters quantify the visual and non-visual effects of the filters beyond the spectral transmittance, which will eventually aid in developing a mechanistic understanding of how different filters affect physiology.
Publisher: Cold Spring Harbor Laboratory
Date: 06-09-2019
DOI: 10.1101/759134
Abstract: The melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) are characterised by a delayed off-time following light offset. Here, we exploited this unusual physiologic property to characterise the exquisite sensitivity of the human circadian system to flashed light. In a 34-hour in-laboratory between-subjects design, we examined variable-intensity (3-9500 photopic lux n=28 participants) full-field flashes at fixed duration (2 ms), and variable-duration (10 μ s-10 s) full-field flashes at fixed intensity (2000 photopic lux n=31 participants) delivered using eye masks. We measured the circadian phase shift of the dim-light melatonin onset (DLMO) on the subsequent evening, acute melatonin suppression, objective alertness, and subjective sleepiness during the flash sequence. We find a clear dose-response relationship between flash intensity and the induced circadian phase shift, with an approximate increase of 10 minutes of phase delay for each ten-fold increase in photopic illuminance, but no parametric relationship between flash duration and induced circadian phase shift.
Publisher: Wiley
Date: 11-2019
DOI: 10.1111/OPO.12648
Abstract: Optical filters and tints manipulating short‐wavelength light (sometimes called ‘blue‐blocking’ or ‘blue‐attenuating’ filters) are used in the management of a range of ocular, retinal, neurological and psychiatric disorders. In many cases, the only available quantification of the optical effects of a given optical filter is the spectral transmittance, which specifies the amount of light transmitted as a function of wavelength. We propose a novel physiologically relevant and retinally referenced framework for quantifying the visual and non‐visual effects of these filters, incorporating the attenuation of luminance ( luminous transmittance ), the attenuation of melanopsin activation ( melanopsin transmittance ), the colour shift , and the reduction of the colour gamut ( gamut reduction ). Using these criteria, we examined a novel database of spectral transmittance functions of optical filters ( n = 121) which were digitally extracted from a variety of sources. We find a large ersity in the alteration of visual and non‐visual properties. The spectral transmittance properties of the examined filters vary widely, in terms of shapes and cut‐off wavelengths. All filters show relatively more melanopsin attenuation than luminance attenuation (lower melanopsin transmittance than luminous transmittance). Across the data set, we find that melanopsin transmittance and luminous transmittance are correlated. We suggest that future studies and examinations of the physiological effects of optical filters quantify the visual and non‐visual effects of the filters beyond the spectral transmittance, which will eventually aid in developing a mechanistic understanding of how different filters affect physiology. We strongly discourage comparing the downstream effects of different filters on, e.g. sleep or circadian responses, without considering their effects on the retinal stimulus.
No related grants have been discovered for Manuel Spitschan.