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Scientists say that intrinsically photosensitive retinal ganglion cells (ipRGCs) in the eye are activated by bright light and affect the brain's mood, memory and learning centres.
Where once humans waking hours coincided with the rising and setting of the sun, nowadays we're exposed to bright lights well into the evening and it could have consequences.
Professor Samer Hattar, who led the study on mice, found that those exposed to bright lights and then darkness on a 3.5-hour rotation had increased levels of the stress hormone cortisol and displayed "depression-like behaviours".
Prof Hattar explained: "Of course, you can't ask mice how they feel, but we did see an increase in depression-like behaviours, including a lack of interest in sugar or pleasure seeking, and the study mice moved around far less during some of the tests we did."
That's not all - the rodents did not learn as quickly or remember tasks as well as those on a regular cycle of light and dark.
The researchers believe that humans would react in much the same way, as both have ipRGCs in their eyes which have a similar impact on the brain.
Prof Hattar, whose study was published in the journal Nature, said the results suggest prolonged and regular exposure to bright lights in the evening or at night could have an ongoing negative effect on their mood.
He added: "I'm not saying we have to sit in complete darkness at night, but I do recommend that we should switch on fewer lamps, and stick to less intense light bulbs."
Do you regularly use a laptop or tablet late into the evening? Have you noticed it affecting your mood? Leave your comments below...