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Mar 31

How Light Affects the Brain

lightTwo recent articles that I reviewed highlight the accumulating evidence that something as simple as sunlight has profound impacts on brain biology.

When I suggest to people that they pay attention to daily light exposure and, particularly, to getting bright light for 45 minutes every morning, I am often looked at with skepticism. “Sure doc,” I hear the other person thinking, “If you say so, but I want to talk about things that really can change my mood for the better… I want to talk about medications…”

Steven Dubovsky reviewed an article in Nature Neuroscience that demonstrate that light exposure changes the activity of genes in the brain (Azzi A et al., Nat Neurosci 2014 Mar 17:377). The authors of the study found that there were major changes in the brains of rats exposed to daily morning light, compared with rats that did not have the regular experience of daily light. They also showed that this widespread alteration in genes in the brain, could be normalized with a week or so of regular light exposure.

Other authors have shown (Fisher PM et al., Biol Psychiatry 2013 Dec 19) that one of the (perhaps surprising) effects of not having light exposure is of increased activation of the amygdala (the part of the brain that reacts to threats and creates the emotion of fear). Animals without normal light cycles tended to misinterpret normal events in the environment as threats. This might help explain why disrupted circadian (daily) rhythms can be associated with depression.

Remember when your mother said, “take your vitamins?” It turns out that daily light might be even more important for good mental and physical health

1 ping

  1. Sleep and the Lunar Cycle - MoodSurfing ™

    […] This is how the internal circadian clocks work. For more information about the circadian clocks go here. […]

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