Credit: LL Twistiti; Flickr CC BY-NC 2.0
A few weeks ago, I wrote about about how important light is to human health, mainly for its ability to govern Circadian rhythms. I shared a nifty little initiative called The Photon Project that’s building glass houses in the interest of living, more healthily, in the light.
And then just last week, Jessica informed us that not only is light important, but it’s so important that 2015 has been proclaimed the International Year of Light.
So you could say that optics and all things light are getting some time in the spotlight.
One of the more recognizable forms of optics, optical fibers are critical for the massive transfer of information in today’s data and communications deluge. These thin yet flexible strands of glass allow data to flow fast and free around the globe, transferring incredible amounts of data over huge distances. And those distances are reaching further than ever before.
[Don’t know much about fiber optics? Brush up on the basics with Corning Inc.’s “Fiber 101” video. A less tutorial-esque explanation of how optical fibers are made can be found in the optical fiber episode of the TV series “How It’s Made,” if you can find the video.]
But fiber optics have another use—to improve human health. Fiber optics are already used in medicine as endoscopy lights, medical sensors, in blankets to treat jaundiced babies, and to activate photosensitive chemotherapy drugs within the body (called photodynamic therapy).
Now researchers at Vanderbilt University may have found yet another use for optical fibers—to treat Circadian rhythm problems, including insomnia and jet lag.
“We found we can change an animal’s sleep/wake rhythms by artificially stimulating the neurons in the master biological clock, which is located in an area of the brain called the suprachiasmatic nucleus (SCN), with a laser and an optical fiber,” says Douglas McMahon, biology professor and senior author of the new study, in a Vanderbilt press release.
(L to R) Researchers Jeff Jones, Michael Tackenberg, and Douglas McMahon. Credit: Steve Green; Vanderbilt
Using mice, the researchers found that they could alter the activity of the animals’ biological clocks by adjusting the activity of neurons in that area of the brain.
Previous to this work, scientists thought that biological clock determined neuron activity—and that this control was a one-way street. The new work suggests, in fact, the road is bidirectional. The biological clock governs neuron activity, but neuron activity can also re-adjust the biological clock.
Although the studies were performed in mice, the critters have similar biological clocks as humans. So the scientists are hopeful that their work will translate well into humans. Circadian rhythm disorders, such as insomnia and seasonal affective disorder, could potentially be alleviated with simple light therapy.
For the mouse studies, researchers inserted optical fibers directly into the brain to deliver the light, so serious tweaks would be made to the protocol before human use. “Of course, this exact approach isn’t ready for human use yet,” says doctoral student and author Michael Tackenberg in the release. “But others are making progress toward eventually using optogenetics as therapy.”
The release continues, “This would involve an experimental technique that uses viruses to insert new genes into cells, which is considered a promising potential treatment for a number of diseases. This could be used to implant optically sensitive proteins in SCN neurons that could be activated by an implanted LED.”
The paper, published in Nature Neuroscience, is “Manipulating circadian clock neuron firing rate resets molecular circadian rhythms and behavior” (DOI: 10.1038/nn.3937).
An optical fiber used to reset mice’s biological clocks. Credit: Steve Green; Vanderbilt