The effects of polychromatic light spectra on the non-visual pathway (360G-Wellcome-102562_Z_13_Z)

Non-image forming responses to light are not a new phenomenon and have been known about for some time; however, it is only in the past decade or so that aphotoreceptive cell in the retinal ganglion cell layer, distinct from the classical rod and cone photoreceptors, was discovered that may be primarily responsible non-image forming responses to light. This type of cell, now named the intrinsically photoreceptive retinal ganglion cell (ipRGC), is maximally sensitive to wavelengths of light at approximately 480nm, in contrast to the classical photoreceptive system which is maximally sensitive to light at around 555nm. Hence, a new field of research has developed to investigate the effects ofvariably stimulating the classical and non-classical photoreceptive systems (equivalently the visual and non-visual systems). No single isolated measure of non-visual pathway stimulation exists, but there are several biological and psychological processes known to be affected by varying light spectra; including: circadian rhythms, sleepiness, alertness and cognitive function. These effects have until recently been studied primarily with narrow-band light. In In this project, we propose to investigate how modulations in the spectra of broad-band, polychromatic lights affect particular non-visual biological and psychological responses to light.