The cold winter months may be responsible for memory problems, for researchers discovered the brains of one species of mouse shrunk during the winter, causing them to have difficulty with some learning skills.
Specifically, a study found that white-footed mice had compromised spatial memory -- the mental map that helps them remember important places in their environment -- during the short days of winter. However, such changes in the brain may be responsible for helping the mice conserve energy to make it through the cold winter season when food is scarce and conditions are severe.
Experiments on Mice
One set of experiments involved 20 adult male white-footed mice. Researchers created an environment where some mice were kept in simulated short, winter days (eight hours) and some were kept in longer, summer days (16 hours) for 13 weeks. Their spatial learning and memory were analyzed using a water maze test in which the mice had to swim to find an escape platform hidden just below the surface of unclear water:
Mice that were kept in short, winter days took longer and swam farther before they located the hidden platform, compared to the long-day mice. In addition, the short-day mice didn't recall the platform location from one day to the next.
A second experiment involved 16 adult white-footed mice that were kept in short or long days for 14 weeks; they were sacrificed after. Researchers then analyzed the differences in brains between mice kept in the two varied conditions:
Mice kept in short days had a smaller brain mass compared to long-day mice. Also, mice in short days had a proportionally smaller hippocampus -- the sector of the brain that houses spatial memory -- as well as changes in spinal density.
So How do These Results Apply to Humans?
Melatonin levels, affected by seasonal changes in sunlight, also control the changes in brain size and function in mammals such as white-footed mice. Melatonin is also found in humans.
Therefore, while there are obvious differences between mice and humans, such studies help researchers gain insight into seasonal brain dysfunctions like seasonal affective disorder (SAD).
Journal of Neuroscience May 4, 2005, Vol. 25: 4521-4526
Ohio State University May 12, 2005
Sunlight plays a crucial role in your overall well-being, and while we don't yet know for sure if it can keep human brains from shrinking, we do know that it can aid in the prevention and treatment of a myriad of common health challenges including:
Conventional medicine's aversion to these facts has had a profoundly negative influence on our culture's health. As is often the case, it is up to you to learn about this valuable asset for your health. Reading the many sunlight-related articles on this site is a great place to start to increase your appreciation of this powerful force for improving your health.
Increasing Sunlight Exposure to Maintain Optimal Health
While it is recommended that everyone get exposure to one hour of sunlight per day -- essential for optimal health -- many people have a difficult time achieving this goal. Whether it's dreary winter weather, the climate you live in or simply time constraints, there seems to be a great deficiency in sunlight exposure among Americans.
That is why I have begun to offer full-spectrum light bulbs that are designed to help you obtain the balanced sunlight that is essential to your physical and mental health.
Using these bulbs, however, are in no way, shape or form superior to getting regular, real sun exposure. Fortunately, many of us have the opportunity to do this at this time of year -- we just need to make time for it.
So please clearly understand that my primary recommendation is to get regular sun exposure (but never to the point that you get burned). That is the absolute best way to get the benefits of sunlight.
If that just isn't possible because you are stuck inside for most of the week, then please consider using healthier light indoors. You don't have to go through the research, time and energy of determining which light bulbs are the best on the market, as I personally have spent much time and effort researching this and found that BioPure light bulbs are one of the most accurate natural full-spectrum light bulbs available.
These light bulbs project full-spectrum light that most closely matches natural daylight and contain the necessary full spectrum of color (imagine the colors of the rainbow), as well as infrared and the three ultraviolet wavelengths.
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Reap Sunshine's Benefits ... Even in Dark Days of Winter!
Valuable Insights Into the Importance of Vitamin D and Sun
The Bright Idea Behind Treating SAD