Figure 4From: The melanocyte photosensory system in the human skin Response to light cycles: Dendricity, serotonin, and melatonin during [a] seasonal cycles and [b] the diurnal photophase. [c] Depicts the phase response curves, near the poles, measuring length of the photophase, with the serotonin/melatonin flux, during transit from winter, with short curves to summer with lengthening curves. [d] Correction of the serotonin/melatonin rhythm by phototherapy during long dark phase in winter.Back to article page