Researchers from Manchester discovered that animals’ bodies clocks, which are how they measure time, can be affected by light and colours. These findings may have important implications on how jet-lag treatment is done currently. Tim Brown (University’s Faculty of Life Sciences) and his colleagues sought to find out if animals’ circadian clocks, or body clocks, were affected by light quality. To determine if animals could use light colour to decide the time of day, they looked at light’s changing patterns around dawn and dusk. The solar angle is predicted by the spectrum composition of ambient lighting. Image: PLOS Biology. We all know that light intensity changes dramatically when the sun rises and sets. Researchers discovered that full-daytime sunlight is much more blue than twilight. Experiments on mice revealed that neurons, which are brain cells and nerve cells, were sensitive to colour changes between yellow-blue than light intensities (brightness) in animal experiments. The artificial sky was then created by Dr. Brown’s colleagues. This simulates the changes in colour and brightness that occur every day. The mice that had been exposed to the artificial sky for several nights showed the most extreme body temperature. This is consistent with what one might expect from nocturnal mammals. The animals were more active when the sun was brighter than the colours. This indicated that the animal’s internal clocks weren’t aligned with the 24-hour daylight-night cycle. The sky is bluer at twilight and midday than it is during the day. In a journal Abstract, the authors conclude that these findings reveal a new sensor mechanism to tell time of day. This sensory mechanism would also be useful to other mammalian species with chromatic vision. It might be worth suggesting that passengers flying through multiple time zones wear sunglasses. These only reduce the intensity of light and are not a good solution to jetlag. Citation: “Colour as a Signal to Entrain the Mammalian Circadian Time Clock,” Lauren Walmsley and Lydia Hanna. Alexander West, Franck Mouland. Alexander West, Andrew R. Smedley. David A. Bechtold. Ann R. Webb. Robert J. Lucas. PLOS Biology. 17 April. 2015. DOI: 10.1371/journal.pbio. 1002127.
Colours influence animal’s biological clocks
