Biology subjects

Spitschan, M.

Publications and source records attributed to Spitschan, M..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Sneezing in response to bright light exposure: A case study in a photic sneezer

BackgroundThe photic sneeze reflex (PSR) is a widespread, yet understudied phenomenon characterised by sneezing in response to bright-light exposure, reportedly affecting around 30% of the general population. Our goals were to collect real-world data to characterise PSR-inducing naturalistic light conditions, and to develop an indoor protocol to reliably induce the PSR in affected individuals using parametric stimuli. MethodsThis study was carried out on one male adult affected by photic sneezing (n=1). To characterise naturalistic light conditions eliciting photic sneezing, real-world light exposure was measured over a 30-day period, while logging PSR events. To study photic sneezing in response to artificial stimuli, a setup including a multi-primary LED source and an integrating sphere was used to present 30-second light stimuli to the participant while collecting pupillometric data with an eye-tracker. Results82 photic sneeze events were recorded, with an average of 2.73 sneezes per day and a range of 1 to 6 sneezes per event. At a sneeze event, illuminance is on average ten times bigger than five minutes before the sneeze event. A significant increase in illuminance is observed around 2 minutes before the sneeze event. Light levels go back down to pre-sneeze levels within 10 minutes after sneezing. Despite exposure to more than 150 stimuli, no sneeze could be artificially induced in the participant. However, a strong tickling sensation was consistently reported, especially for high illuminance settings. ConclusionsReal-world light data confirmed that a sudden increase in environmental lighting conditions can induce photic sneezing. Further analysis could be relevant on instances of illuminance increments not eliciting a photic sneeze. The experimental setup only elicited tickling sensations, but with further testing and optimisation, it is reasonable to assume that it would reliably induce photic sneezes, thereby opening further mechanistic study of this intriguing phenomenon.

neuroscience↗

bioRxiv2024

Reduced and Redundant: Information Processing of Prediction Errors during Sleep

During sleep, the human brain transitions to a sentinel processing mode, enabling the continued processing of environmental stimuli despite the absence of consciousness. Here, we employed advanced information-theoretic analyses, including mutual information (MI) and co-information (co-I), alongside event-related potential (ERP) and temporal generalization analyses (TGA), to characterize auditory prediction error processing across wakefulness and sleep. We hypothesized that a shared neural code would be present across sleep stages, with deeper sleep being associated with reduced information content and increased information redundancy. To investigate this, twenty-nine young healthy participants were exposed to an auditory local-global oddball paradigm during wakefulness and during an 8-hour sleep opportunity monitored via polysomnography in a cross-sectional study. We focused on local mismatch responses to a deviating fifth tone following four standard tones. ERP analyses showed that prediction error processing continued throughout all sleep stages (N1-N3, REM). Mutual information analyses revealed a substantial reduction in the amount of encoded prediction error information particularly during N3 and REM, although ERP amplitudes increased with deeper NREM sleep. In addition, we observed delayed information encoding during sleep and co-information analyses showed that neural dynamics became increasingly redundant with increasing sleep depth. Temporal generalisation analyses revealed a largely shared neural code between N2 and N3 sleep, although it differed between wakefulness and sleep. Here, we showed how the neural code of the sentinel processing mode changes from wake to light to deep sleep and REM, characterised by delayed processing, more redundant and less rich neural information in the human cortex as consciousness wanes. This altered stimulus processing reveals how neural information changes with the changes of consciousness states as we traverse the night.

neuroscience↗

bioRxiv2024

Sex and seasonal variations in melatonin suppression, and alerting response to light

Light influences human physiology and behaviour by regulating circadian rhythms, melatonin secretion, and alertness. Previous research has reported sex differences in melatonin secretion and circadian rhythms, possibly related to womens greater sensitivity to bright light. Other studies have suggested reduced photosensitivity and earlier circadian phases in summer than in winter in mid-latitude regions. This study explores the effects of sex, seasonality, and their combination on melatonin suppression and subjective sleepiness in response to moderate light exposure, considering prior light history and menstrual phases in females. We conducted a controlled, within-subject experiment with 48 healthy adults (18-35 years, 50% female) across different seasons. The study design included two 9-h laboratory sessions, with at least 5-day washout in between. Participants were exposed to dim and moderate light through a screen for 2 hours after their habitual bedtime. Female participants exhibited greater melatonin suppression (+4.69 %) but a lower alerting response (-6.00%) to moderate light compared to males. Both sexes demonstrated increased sensitivity to the NIF effects of light in winter, with stronger melatonin suppression (+18.05 %) and increased alertness (+7.60 %) compared to summer. While prior light history did not significantly impact melatonin suppression or alertness, it was associated with an earlier dim light melatonin onset (DLMO). Females during their luteal phase had earlier DLMO than those in their follicular phase. Our findings indicate an interaction between sex, seasonality, and light exposure in modulating melatonin suppression, emphasising the need for personalised light exposure recommendations according to individual biological and environmental contexts.

physiology↗

bioRxiv2024

Lack of evidence for the contribution of cone photoreceptors to human melatonin suppression and alerting response to light at night

Light exposure at night can suppress melatonin production and increase alertness, primarily through the action of melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs). This study investigated whether cone photoreceptors also influence melatonin suppression and subjective alertness using non-visual metameric light emitted from a display. Forty-eight participants with normal trichromatic vision were exposed to three lighting conditions: a baseline (9 lxmEDI), constant background (149 lxmEDI), and cone-modulated flickering light targeting different cone combinations and post-receptoral channels (149 lxmEDI) for 2 hours after their habitual bedtime. Salivary melatonin levels and subjective alertness were measured throughout a 9-h protocol. Bayesian analysis showed that cone-modulated flickering light did not significantly affect melatonin suppression or alertness, providing evidence against the hypothesis that cone photoreceptors contribute to these non-visual effects of light. In conclusion, our results suggest cone photoreceptors do not play a measurable role in lights effects on melatonin suppression and subjective alertness at night.

physiology↗

bioRxiv2024

Afternoon to early evening bright light exposure reduces later melatonin production in adolescents

Whether light exposure during the day reduces non-visual light effects later in the evening has not been studied in adolescents. We investigate whether afternoon-early evening (AEE) light interventions (130 lx, 2500 lx, 4.5 hours, compared to 6.5 lx) would increase melatonin levels during later evening light exposure (130 lx) in a counterbalanced crossover study with 22 adolescents (14-17 years, 11 female). Contrary to our hypothesis, evening melatonin levels decreased after AEE bright light exposure, while sleepiness and vigilance were unaffected, and skin temperature showed no clear changes. The AEE light had acute alerting effects and bright light exposure in the 32 hours before laboratory entry was associated with higher evening melatonin and sleepiness. These findings suggest that bright AEE light increases alertness but may delay melatonin production by interfering with circadian rhythms. The study highlights the complex effects of light timing and its implications for managing adolescents light exposure.

neuroscience↗

bioRxiv2024

Visually Evoked 40 Hz Gamma Activity Enhanced by Transcranial Electrical Stimulation

ObjectiveTranscranial Electrical Stimulation and Visual Stimulation in the gamma band (30-100 Hz, especially 40 Hz) are increasingly used to study and even enhance human cognition. Combining both techniques would be of scientific and clinical value, provided that Steady-State Visually Evoked Potentials (SSVEPs) are measured concurrently to determine any neuronal effects of the electrical brain stimulation. This poses a substantial methodological challenge. We aimed to demonstrate that recording visually evoked 40 Hz activity with EEG during electrical brain stimulation is possible and to explore potential interactions. ApproachWe tested if electrical and visual stimulation might interact depending on which brain areas are electrically stimulated (Experiment 1; N=25) and how closely the respective frequencies match (Experiment 2; N=25). Experiment 3 (N=25) assessed how effectively the data processing pipeline can mitigate electrical artefacts and recover real evoked neuronal activity. SSVEPs were processed and analysed in the time domain using an optimised adaptive template subtraction approach. Main Results40 Hz SSVEPs were successfully recorded during frequency-matched electrical stimulation applied between central and occipital regions. Waveform correlations revealed that SSVEPs from combined visual and electrical stimulation were more similar in shape to baseline SSVEPs from visual stimulation alone than to control data from electrical stimulation alone. Accordingly, during combined stimulation, the recovered signals were stronger in amplitude than the electrical control data. We found no evidence of interactions between electrical and visual stimulation. SignificanceWe demonstrated that 40 Hz SSVEPs can be reliably measured with EEG during frequency-matched electrical brain stimulation, distinguishing neuronal activity from electrical or physiological confounds. This method enables fundamental and clinical researchers to combine rhythmic sensory and electrical stimulation in the gamma band and concurrently quantify neuronal electrophysiological effects.

neuroscience↗

bioRxiv2023

Regulation of pupil size in natural vision across the human lifespan

Vision is mediated by light passing through the aperture of the eye, the pupil, which changes in diameter from ~2 to ~8 mm from the brightest to the darkest illumination. In addition, with age, mean pupil size declines. In laboratory experiments, factors affecting pupil size can be experimentally controlled or held constant, but how the pupil reflects changes in retinal input from the visual environment under natural viewing conditions is not clear. Here, we address this question in a field experiment (N=83, 43 female, age: 18-87 years) using a custom-made wearable video-based eye tracker with a spectroradiometer measuring spectral irradiance in the approximate corneal plane. Participants moved in and between indoor and outdoor environments varying in spectrum and engaged in a range of everyday tasks. Our real-world data confirm that light-adapted pupil size is determined by light intensity, with clear superiority of melanopic over photopic units, and that it decreases with increasing age, yielding steeper slopes at lower light levels. We find no indication that sex, iris colour or reported caffeine consumption affect pupil size. Taken together, the data provide strong evidence for considering age in personalised lighting solutions and for using melanopsin-weighted light measures to assess real-world lighting conditions.

neuroscience↗

bioRxiv2023

Effects of calibrated blue-yellow (-S+) changes in light on the human circadian clock

Evening exposure to short-wavelength light can acutely affect the circadian clock located in the suprachiasmatic nuclei, sleep, and alertness. The intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin are thought to be the primary drivers of these effects. Much less is known about the contribution of the colour-sensitive cones. Using calibrated silent-substitution changes in light colour along the blue-yellow axis, we investigated whether mechanisms of colour vision affect the human circadian system and sleep. In a 32.5-h repeated within-subjects protocol, 16 healthy participants (8 women, 18-35 years old) were exposed to three different light scenarios for 1 h starting 30 min after habitual bedtime: a control condition ("background", 93.5 photopic lux), intermittently flickering yellow-bright light (1 Hz, 30s on-off, 123.5 photopic lux), and intermittently flickering blue-dim light (1 Hz, 30s on-off; 67.0 photopic lux). Importantly, there was no difference in melanopsin excitation (163.2{+/-}2.1 lux melanopic EDI) between the three lighting conditions, allowing us to determine the unique contribution of the blue-yellow colour system. Our analyses did not yield conclusive evidence for differences between the three lighting conditions regarding circadian melatonin phase delays, melatonin suppression, subjective sleepiness, psychomotor vigilance, or sleep. Thus, in this study, we found no evidence that evening light changing along the blue-yellow dimension under moderate light levels typical for room illumination has a major impact on the human circadian clock or sleep. Our work underscores the previously demonstrated primary role of melanopsin-containing ipRGCs in mediating these effects.

neuroscience↗

bioRxiv2023

Temporal sensitivity for achromatic and chromatic flicker across the visual cortex

The retinal ganglion cells (RGCs) receive different combinations of L, M, and S cone inputs and give rise to one achromatic and two chromatic post-receptoral channels. Beyond the retina, RGC outputs are subject to filtering and normalization along the geniculo-striate pathway, ultimately producing the properties of human vision. The goal of the current study was to determine temporal sensitivity across the three post-receptoral channels in subcortical and cortical regions involved in vision. We measured functional magnetic resonance imaging (MRI) responses at 7 Tesla from three participants (two males, one female) viewing a high-contrast, flickering, spatially-uniform wide field (~140{degrees}). Stimulus flicker frequency varied logarithmically between 2 and 64 Hz and targeted the L+M+S, L-M, and S-[L+M] cone combinations. These measurements were used to create temporal sensitivity functions of primary visual cortex (V1) across eccentricity, and spatially averaged responses from lateral geniculate nucleus (LGN), V2/V3, hV4, and V3A/B. Functional MRI responses reflected known properties of the visual system, including higher peak temporal sensitivity to achromatic vs. chromatic stimuli, and low-pass filtering between the LGN and V1. Peak temporal sensitivity increased across levels of the cortical visual hierarchy. Unexpectedly, peak temporal sensitivity varied little across eccentricity within area V1. Measures of adaptation and distributed pattern activity revealed a subtle influence of 64 Hz achromatic flicker in area V1, despite this stimulus evoking only a minimal overall response. Comparison of measured cortical responses to a model of integrated retinal output to our stimuli demonstrates that extensive filtering and amplification is applied to post-retinal signals. Significance StatementWe report the temporal sensitivity of human visual cortex across the three canonical post-receptoral channels from central vision to the far periphery. Functional MRI measurements of responses from the LGN, V1, and higher visual cortical areas demonstrate modification of temporal sensitivity across the visual hierarchy. This includes amplification of chromatic signals between the LGN and V1, and an increase in peak temporal sensitivity in visual areas beyond V1. Within V1, we find a surprising stability of peak temporal sensitivity in the periphery for all three post-receptoral directions. Comparison of our results to a model of retinal output demonstrates the presence of substantial post-retinal filtering, yielding greater uniformity of responses across area V1 than would be predicted from unmodified retinal signals.

neuroscience↗

bioRxiv2023

PySilSub: An open-source Python toolbox for implementing the method of silent substitution in vision and nonvisual photoreception research

The normal human retina contains several classes of photosensitive cell--rods for low-light vision, three cone classes for daylight vision, and intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing melanopsin for non-image-forming functions including pupil control, melatonin suppression and circadian photoentrainment. The spectral sensitivities of the photoreceptors overlap significantly, which means that most lights will stimulate all photoreceptors, to varying degrees. The method of silent substitution is a powerful tool for stimulating individual photoreceptor classes selectively and has found much use in research and clinical settings. The main hardware requirement for silent substitution is a spectrally calibrated light stimulation system with at least as many primaries as there are photoreceptors under consideration. Device settings that will produce lights to selectively stimulate the photoreceptor(s) of interest can be found using a variety of analytic and algorithmic approaches. Here we present PySilSub (https://github.com/PySilentSubstitution/pysilsub), a novel Python package for silent substitution featuring flexible object-oriented support for individual colorimetric observer models (including human and mouse observers), multi-primary stimulation devices, and solving silent substitution problems with linear algebra and constrained numerical optimisation. The toolbox is registered with the Python Package Index and includes example data sets from various multi-primary systems. We hope that PySilSub will facilitate the application of silent substitution in research and clinical settings.

neuroscience↗

bioRxiv2023

Inclusion, reporting and analysis of demographic variables in chronobiology and sleep research

Many aspects of sleep and circadian physiology appear to be sensitive to participant-level characteristics. While recent research robustly highlights the importance of considering participant-level demographic information, it is not clear to what extent this information is available within the large body of existing literature. This article investigates study sample characteristics within the published sleep and chronobiology research over the past 40 years. 6,777 articles were identified and a random sample of 20% was included. The reporting of sample size, age, sex, gender, ethnicity, level of education, socio-economic status, and profession of the study population was scored, and any reported aggregate summary statistics for these variables were recorded. We found that while >90% of studies reported age or sex, all other variables were reported in <25% of cases. Reporting quality was highly variable, indicating an opportunity to standardize reporting guidelines for participant-level characteristics to facilitate meta analyses. SummaryIn this article, we address the question of how representative, diverse and inclusive are published articles in sleep and chronobiology research. We analyzed a sample of >1300 articles published in sleep and chronobiology journals between 1979 and 2019 for its inclusion, reporting and analysis of study population characteristics, including age, sex, gender, race/ethnicity, level of education, socio-economic status, and profession. We found that while >90% of studies reported age or sex, all other variables were reported in <25% of cases, with the frequency of reporting changing over time. We identify opportunities for improving the reporting of demographic variables. Research AgendaFuture research needs to: 1. Establish schemas for reporting demographic variables in a harmonized way across geographical and cultural contexts; 2. Identify gaps in the sleep and chronobiology literature with respect to understudied populations; 3. Understand the extent to which research practices allow for the inclusion of diverse populations in all stages of the research cycle, and how this can exacerbate health inequities. Practice PointsO_LIPublished studies on circadian and sleep physiology should be carefully examined. C_LIO_LIReporting of demographic variables should be done deliberately and systematically. C_LIO_LIInclusion and diversity of different populations across the field needs to be ensured. C_LI

neuroscience↗

bioRxiv2023

ENLIGHT Consensus Checklist and Guidelines for reporting laboratory studies on the non-visual effects of light in humans

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.

neuroscience↗

bioRxiv2023

Power analysis for human melatonin suppression experiments

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 individuals differ substantially in their melatonin-suppressive response to light, with the most sensitive individuals being up to 60 times more sensitive than the least sensitive individuals. Planning experiments with melatonin suppression as an outcome needs to incorporate these individual 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 (sample size, individual-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.

neuroscience↗

bioRxiv2022

Light targeting the melanopic system suppresses melatonin, but does not alter sleepiness, vigilance, sensory processing, or sleep

Pre-sleep exposure to short-wavelength light suppresses melatonin and decreases sleepiness with activating effects extending to sleep. This has mainly been attributed to melanopic effects, but mechanistic insights are missing. Thus, we investigated whether two light conditions only differing in the melanopic effects (123 vs. 59 lux melanopic EDI) differentially affect sleep besides melatonin. Additionally, we studied whether the light differentially modulates sensory processing during wakefulness and sleep. Twenty-nine healthy volunteers (18-30 years, 15 women) were exposed to two metameric light conditions (high-vs. low-melanopic, {approx}60 photopic lux) for 1 hour ending 50 min prior to habitual bed time. This was followed by an 8-h sleep opportunity with polysomnography. Objective sleep measurements were complemented by self-report. Salivary melatonin, subjective sleepiness, and behavioural vigilance were sampled at regular intervals. Sensory processing was evaluated during light exposure and sleep on the basis of neural responses related to violations of expectations in an oddball paradigm. We observed suppression of melatonin by {approx}14 % in the high-compared to the low-melanopic condition. However, conditions did not differentially affect sleep, sleep quality, sleepiness, or vigilance. A neural mismatch response was evident during all sleep stages, but not differentially modulated by light. Suppression of melatonin by light targeting the melanopic system does not automatically translate to acutely altered levels of vigilance or sleepiness or to changes in sleep, sleep quality, or basic sensory processing. Given contradicting earlier findings and the retinal anatomy, this may suggest that an interaction between melanopsin and cone-rod signals needs to be considered. Statement of SignificanceMetameric light allows to mechanistically investigate the contribution of one specific retinal receptor. Using this approach, we here investigated the effects of high-vs. low-melanopic light for 1 hour in the evening at ecologically valid screen illuminance ({approx}60 photopic lux). Going beyond earlier research, we also investigated effects on sleep. We found that despite significant suppression of melatonin, other endpoints including sleep and sleep quality were not differentially affected. This underlines that melatonin suppression does not automatically translate to alterations of sleep, sleepiness, or vigilance. Further, it suggests that melanopsin effects may need to be studied in the context of cone-rod signals. Future research should thus investigate the relevance of such an interaction, which may vary between endpoints.

neuroscience↗

bioRxiv2021

Hyperspectral characterisation of natural illumination in woodland and forest environments

Light in nature is complex and dynamic, and varies along spectrum, space, direction, and time. While both spectrally resolved measurements and spatially resolved measurements are widely available, spectrally and spatially resolved measurements are technologically more challenging. Here, we present a portable imaging system using off-the-shelf components to capture the full spherical light environment in a spectrally and spatially resolved fashion. The method relies on imaging the 4{pi}-steradian light field reflected from a mirrored chrome sphere using a commercial hyperspectral camera (400-1000 nm) from multiple directions and an image-processing pipeline for extraction of the mirror sphere, removal of saturated pixels, correction of specular reflectance of the sphere, promotion to a high dynamic range, correction of misalignment of images, correction of intensity compression, erasure of the imaging system, unwrapping of the spherical images, filling-in blank regions, and stitching images collected from different angles. We applied our method to Wytham Woods, an ancient semi-natural woodland near Oxford, UK. We acquired a total of 168 images in two sites with low and high abundance of ash, leading to differences in canopy, leading to a total 14 hyperspectral light probes. Our image-processing pipeline corrected small (<3 {degrees}) field-based misalignment adequately. Our novel hyperspectral imaging method is adapted for field conditions and opens up novel opportunities for capturing the complex and dynamic nature of the light environment.

systems biology↗

bioRxiv2021

PyPlr: A versatile, integrated system of hardware and software for researching the human pupillary light reflex

We introduce PyPlr--a versatile, integrated system of hardware and software to support a broad spectrum of research applications concerning the human pupillary light reflex (PLR). PyPlr is a custom Python library for integrating a research-grade video-based eye-tracker system with a light source and streamlining stimulus design, optimisation and delivery, device synchronisation, and extraction, cleaning, and analysis of pupil data. We additionally describe how full-field, homogenous stimulation of the retina can be realised with a low-cost integrating sphere that serves as an alternative to a more complex Maxwellian view setup. Users can integrate their own light source, but we provide full native software support for a high-end, commercial research-grade 10-primary light engine that offers advanced control over the temporal and spectral properties of light stimuli as well as spectral calibration utilities. Here, we describe the hardware and software in detail and demonstrate its capabilities with two example applications: 1) pupillometer-style measurement and parametrisation of the PLR to flashes of white light, and 2) comparing the post-illumination pupil response (PIPR) to flashes of long and short-wavelength light. The system holds promise for researchers who would favour a flexible approach to studying the PLR and the ability to employ a wide range of temporally and spectrally varying stimuli, including simple narrowband stimuli.

physiology↗

bioRxiv2021

Beyond colour gamuts: Novel metrics for thereproduction of photoreceptor signals

Colour gamuts describe the chromaticity reproduction capabilities of a display, i.e. its ability to reproduce the relative cone excitations from real-world radiance spectra. While the cones dominate "canonical" visual function (i.e. perception of colour, space, and motion) under photopic light levels, they are not the only photoreceptors in the human retina. Rods and melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) also respond to light and contribute to both visual and non-visual light responses, including circadian rhythms, sleep-wake control, mood, pupil size, and alertness. Three-primary display technologies, with their focus on reproducing colour, are not designed to reproduce the rod and melanopsin excitations. Moreover, conventional display metrics used to characterize three-primary displays fail to describe the displays ability (or inability) to reproduce rod and melanopsin excitations, and thus do not capture the displays ability to reproduce the full human physiological response to light. In this paper, three novel physiologically relevant metrics are proposed for quantifying the reproduction and distortion of the photoreceptor signals by visual displays. A novel equal-luminance photoreceptor excitation diagram is proposed, extending the well-known MacLeod-Boynton chromaticity diagram, to allow visualizations of the five-dimensional photoreceptor signal space in a three-dimensional projection.

neuroscience↗

bioRxiv2020

Transparency and open science reporting guidelines in sleep research and chronobiology journals

"Open science" is an umbrella term describing various aspects of transparent and open science principles. The adoption of open science principles at different levels of the scientific process (e.g., individual researchers, laboratories, institutions) has been rapidly changing the scientific research landscape in the past years, but uptake of these principles differ from discipline to discipline. Here, we asked to what extent journals in the field of sleep and chronobiology research encourage or even require following transparent and open science principles in their author guidelines. To this end, we scored the author guidelines of a comprehensive set of 28 sleep and chronobiology journals, including the major outlets in the field, using the standardised Transparency and Openness (TOP) Factor. This instrument rates the extent to which journals encourage or require following various aspects of open science, including data citation, data transparency, analysis code transparency, materials transparency, design and analysis guidelines, study pre-registration, analysis plan pre-registration, replication, registered reports, and the use of open science badges. Across the 28 journals, we find low values on the TOP Factor (median [25th, 75th percentile] 2.5 [1, 3], min. 0, max. 9, out of a total possible score of 28). This suggests an opportunity for sleep and chronobiology journals to further support the recent developments by implementing transparency and openness principles in their guidelines and making adherence to them mandatory.

scientific communication and education↗