Summary:“Secret to Body’s 24-hour Time Clock is in the Eye”
-San Francisco Chronicle publishing from Feb. 8, 2002
In the 1990’s it was found that blind people could regulate and alter their internal clocks with light even without a functional visual system. It has now been discovered that the rods and cones cannot solely be responsible for detection of light, but a specialized, light sensing cell in the eye interprets and delivers messages to the suprachiasmatic nucleus (SCN) buried within the brain. These newly found cells are spidery in nature and contain the photopigment melanopsin, which acts as the crucial messenger. These receptors detect subtle changes in light and relay this information to the SCN, where mood and wakefulness are known to be physiologically regulated. These findings of a new class of retinal photoreceptor are being explored in Europe and the U.S. and have been published in various research journals including the February addition of “the Journal of Science.” It has been hypothesized that these same cells may also be responsible for dilation of the iris in the eye’s pupillary system.
Although this is extremely exciting research and may lead to new ways of coping with jet lag, winter depression, and other light related physiological problems, more research is needed to entangle the brain’s role. Current research with engineered animals that lack the melanopsin gene may give more clues to how light cues are obtained and delivered to the brain’s internal clock.
Previous Article
Return to Animal Physiology Forum
If you would like to post a response to this article, use this form.
Animal Physiology Forum