40 Hz Visual Stimulation During Sleep Evokes Neuronal Gamma Activity in NREM and REM Stages.

Study Objectives: Visual stimulation at 40 Hz is being tested as a non-invasive approach against dementias such as Alzheimer's disease. Applying it during sleep could increase convenience, duration, and efficacy of stimulation. Here, we tested the feasibility of 40 Hz visual stimulation during sleep in a proof-of-concept study.

Power analysis for personal light exposure measurements and interventions.

Background: Light exposure regulates the human circadian system and more widely affects health, well-being, and performance. With the rise in field studies on light exposure's effects, the amount of data collected through wearable loggers and dosimeters has also grown. These data are more complex than stationary laboratory measurements.

Behavioural determinants of physiologically-relevant light exposure.

Light exposure triggers a range of physiological and behavioural responses that can improve and challenge health and well-being. Insights from laboratory studies have recently culminated in standards and guidelines for measuring and assessing healthy light exposure, and recommendations for healthy light levels. Implicit to laboratory paradigms is a simplistic input-output relationship between light and its effects on physiology.

Protocol for a prospective, multicentre, cross-sectional cohort study to assess personal light exposure.

Light profoundly impacts many aspects of human physiology and behaviour, including the synchronization of the circadian clock, the production of melatonin, and cognition. These effects of light, termed the non-visual effects of light, have been primarily investigated in laboratory settings, where light intensity, spectrum and timing can be carefully controlled to draw associations with physiological outcomes of interest. Recently, the increasing availability of wearable light loggers has opened the possibility of studying personal light exposure in free-living conditions where people engage in activities of daily living, yielding findings associating aspects of light exposure and health outcomes, supporting the importance of adequate light exposure at appropriate times for human health.