Most of us feel sleepy in a dimly lit place and alert in a bright place. The biological mechanism behind this was unexplained till now. The answer seems to be that specialized cells in the retina detect light and send brightness information to those regions of the brain that regulate sleep and levels of arousal.
The biological mechanism was discovered when the research team worked on mice in which the cells had been genetically turned-off. Mice normally sleep when it is daylight and wake up in the dark. The researchers observed that those mice in which the light-sensitive cells were turned off stayed wide-awake even when the lights were on.
According to their study published in the journal Nature Neuroscience,
the team has been able to track the sleep pathway to the brain, showing that the retinal ganglion cells directly activated two sleep-inducing centers there.
Professor Russell Foster, the lead researcher said, "By targeting the specific mechanism controlling the action of retinal ganglion cells, it may be possible in the future to develop sophisticated treatments to regulate the sleep-wake cycles."
A multibillion-dollar sleeping pill market thrives on developing and selling a lot many drugs to regulate the sleep-wake cycles. But current medicines are not very efficient and sophisticated and the drugs have side effects.
The researchers opine the study will pave the way to a new class of sleeping pills and stimulants that would have the same effect as bright light, or darkness, depending on how the drug is designed.
The research is still at an early stage and scientists have yet to establish if the same processes affecting mice that are nocturnal by nature, will work in humans.