SBIR-STTR Award

The light-presentation protocol is an essential feature of circadian rhythm research. The day-night cycle entrains self-sustaining internal pacemakers whose periods may differ from 24 hours. A major problem in the laboratory has been the arbitrariness of illumination regimens. Sudden transitions between darkness and bright light, for example, can disrupt normal circadian adjustment by "shocking" lights and denial of the natural entrainment signal. We are developing an algorithm for naturalistic simulation of illumination changes at specifiable latitudes, day of year, and cloud factor. The project will refine the algorithm and apply it toward the design of an Illuminator mechanism for general laboratory use. The device will simulate outdoor conditions (starlight, moonlight, twilight, and daylight) within a range of 0 to 3000 lux by means of motor driven vanes and electronic dimming. Behavioral tests will concentrate on circadian food- and water-ingestion patterns in a diurnal (ring dove) and nocturnal (rat) species. Subsequent tests will provide an "escape from light" option, allowing the animal self-controlled exposure to veridical outdoor light levels, in simulation of burrowing, If successful, an expanded version of this apparatus will be proposed for potential use in circadian phototherapy for seasonal-depressive disorders.

Thesaurus Terms:
biomedical engineering, instrumentation not clinically oriented, bioperiodicity, circadian rhythms, environmental health, lighting models, mathematical, nutrient intake activity, feeding (eating) behavior, optics, light intensity, computer simulation birds, mammals, rodents, myomorpha, rats (laboratory), nutrition related control tag, psychological tests, behavior assessment-measurement, computer programming

Naturalistic daily illumination patterns are either absent or arbitrarily modified in many modern living, working and laboratory environments. Evidence points to deleterious effects of inadequate daily illumination on health, mood, sleep, and productivity. The day-night cycle is essential for adjustment of circadian physiological timekeeping, and traditional mimics in the laboratory -- involving sudden transitions between darkness and bright light -- pose unnecessarily shocking disruptions. We are developing an alternative system in which gradual naturalistic twilights are presented, closely representative of outdoor illumination patterns at any time of year and latitude on earth. The light source is attenuated continuously by means of a unique, comprehensive 24-hour computer algorithm and precision motor-control system that drives light-blocking vanes. (Disclosure Document #139208, U.S. Pat. Trdmrk. Off.) In Phase II of this project, we will refine the instrument for widely-varying scientific, industrial, and home-use applications. Demonstration research will test the utility of the system in five light-dependent biomedical applications: the treatment of seasonal depressive illness; sleep and activity patterns in early human infancy; circadian ingestive patterns in the laboratory rat; fetal development and maternal physiology in the sheep; and reproductive viability in the laboratory primate breeding colony.

Thesaurus Terms:
biomedical engineering, instrumentation clinically oriented, bioperiodicity, circadian rhythms, environment controlled, environmental health, lighting optics, light intensity, phototherapy computer (general) incl computer data processing (general)