Study findings suggest orange light causes people to be more alert

by Bob Yirka weblog
Credit: Wikipedia

(Medical Xpress)—A team of researchers in Belgium has found that people exposed to orange light exhibit greater brain activity than those exposed to blue light. In their paper published in Proceedings of the National Academy of Sciences, the team describes how they studied brain activity in volunteers undergoing fMRI scanning while different colored lights were shined into their eyes and how it showed that orange light might have an impact on the circadian rhythm.

The research team was studying melanopsin—a sensitive pigment in . Prior research has suggested that the amount of melanopsin present has an impact on the circadian rhythm of certain animals, possibly including humans. To learn more, the researchers sought out volunteers to undergo fMRI scans as lights were shined in their eyes. The idea was to find out if different light colors impacted melanopsin differently.

Each of 16 volunteers was treated to a ten minute shot of blue or orang light as their brains were being scanned. During the test, the volunteers were asked to perform a memory test, to engage the brain. Afterwards, each participant had their eyes covered for 70 minutes, to allow melanopsin to relax. They then went through the same test again, this time with green light.

In studying the brain scans, the researchers noted increased when the volunteers were exposed to orange light, but not blue light. They also found a slight increase when exposed to . The areas of the brain that became active, the researchers noted, were those that are believed to be related to cognitive abilities and an overall level of alertness.

16 young and health participants performed an auditory cognitive task while exposed to a test light. Brain areas in orange responded more to the test light if participants had been exposed to orange light 70 minutes earlier. 1. Thalamus; 2. Dorsolateral prefrontal cortex; 3. Ventrolateral prefrontal cortex. These areas are important in the regulation of alertness and complex cognitive processes. Credit: ULg CRC

The researchers speculate that melanopsin serves as a sort of switch, cueing the brain to when it's time to be more or less alert. Prior research has shown that orange light tends to make melanopsin more sensitive which appears to suggest it serves as a signal to the brain, that it's time to be more alert.

The study doesn't actually prove that orange light makes people more alert, or that it has an impact on the circadian rhythm, but it does hint at a possible link, which suggests that more research needs to be done. If both turn out to be true it could mean it might be a smart idea to install orange lighting in places where people need to be most alert (schools, operating rooms, etc.) or that those that suffer from insomnia, should never use such lamps.

More information: Photic memory for executive brain responses, PNAS, Sarah Laxhmi Chellappa, DOI: 10.1073/pnas.1320005111

Abstract
Light is a powerful stimulant for human alertness and cognition, presumably acting through a photoreception system that heavily relies on the photopigment melanopsin. In humans, evidence for melanopsin involvement in light-driven cognitive stimulation remains indirect, due to the difficulty to selectively isolate its contribution. Therefore, a role for melanopsin in human cognitive regulation remains to be established. Here, sixteen participants underwent consecutive and identical functional MRI recordings, during which they performed a simple auditory detection task and a more difficult auditory working memory task, while continuously exposed to the same test light (515 nm). We show that the impact of test light on executive brain responses depends on the wavelength of the light to which individuals were exposed prior to each recording. Test-light impact on executive responses in widespread prefrontal areas and in the pulvinar increased when the participants had been exposed to longer (589 nm), but not shorter (461 nm), wavelength light, more than 1 h before. This wavelength-dependent impact of prior light exposure is consistent with recent theories of the light-driven melanopsin dual states. Our results emphasize the critical role of light for cognitive brain responses and are, to date, the strongest evidence in favor of a cognitive role for melanopsin, which may confer a form of "photic memory" to human cognitive brain function.

add to favorites email to friend print save as pdf

Related Stories

Blue light may fight fatigue around the clock

Feb 03, 2014

Researchers from Brigham and Women's Hospital (BWH) have found that exposure to short wavelength, or blue light, during the biological day directly and immediately improves alertness and performance. These ...

More than meets the eye to staying awake, alert

May 13, 2010

Think twice before falling asleep alongside the glare of your computer and TV screens: exposure to dim light from ordinary room lights, computer screens and other electronic devices late at night may be interfering with our ...

Recommended for you

Birthday matters for wiring-up the brain's vision centers

12 hours ago

Researchers at the University of California, San Diego School of Medicine have evidence suggesting that neurons in the developing brains of mice are guided by a simple but elegant birth order rule that allows them to find ...

How is depression related to dementia?

Jul 30, 2014

A new study by neuropsychiatric researchers at Rush University Medical Center gives insight into the relationship between depression and dementia. The study is published in the July 30, 2014, online issue of Neurology, the me ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

julianpenrod
1 / 5 (4) Mar 12, 2014
An eminent fraud to downplay the deleterious effects of the New World Order robbing blue skies from the public through contaminating the air with chemtrails, robbing so many of initiative and imagination to realize the new World Order exists and is trying to enslave humanity and inspiring them to oppose being enslaved. Just because melanopsin becomes sensitized does not mean the individual becomes alert. And notice the technique of retesting the subjects in green light. Why is there no thought that maybe shining green light in their eyes may be having an effect? And why compare orange to blue, why not compare orange to yellow or red or pink or purple? And "evolution" would not have individuals suddenly more alert in the light of evening, when they presumably should be going to sleep to restore themselves than in the middle of the day.
Nik_2213
not rated yet Mar 12, 2014
Does this mean that traditional low-pressure 'orange' Sodium street lighting makes drivers more alert than the modern 'blue-white' high-pressure Sodium luminaires ??