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Turning Up The Heat, Literally — Lasers Make Flies Fall In Love

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FlyCourtship rituals are some of the most fascinating and downright bizarre acts of the natural world. This applies to humans as much as any other creature. Strange stuff makes us fall in love: a look from across a bar, the pitch of a laugh, pheromones. I’ve yet to see a person fall in love at the flip of a switch, but now I can say I’ve seen it happen to a fly.

I’ve written about optogenetics, the rapidly advancing field that studies controlling brain cells and behavior with light, a few times recently. Most optogenetics experiments have been conducted on mice, which scientists prime by adding genetic material to their brain cells and/or using fiber optic cables, which helps facilitate the experiment. But flies are a bit different — they’re too small for fiber optics, and their exoskeletons block most light. So neuroscientists at the Howard Hughes Medical Institute got creative. They decided to pursue thermogenetics — the activation of neurons via heat instead of light. Previous studies had been conducted on the TRPA1 protein, which, when added to a fly’s brain cells, can be activated by heat and change the fly’s behavior. But there’s a lag time of about five minutes between the delivery of heat and the noticeable effects, and scientists wanted a more immediate response.

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Optogenetics Allows Scientists To Control Living Brains With Light

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optogeneticsEarlier this year, we learned that light helps promote brain activity, and the Human Brain Project promises that other neurological insights and breakthroughs aren’t far behind. One of the tools scientists need in order to make progress in their understanding of the human brain and the treatment of brain disorders is a way to observe a working brain and to make purposeful tweaks to its function. Recent innovations in the field of optogenetics, the use of light to control brain cells, may provide one avenue to get to this.

Until recently, MRIs were the best way to see a live brain in action and to observe which parts of the brains activate during certain tasks. Manually stimulating brain cells is tricky and requires wire probes. In 2005, a Stanford University research team announced their discovery that they could control activity with light. Over time, scientists have gotten better at identifying specific clusters of activity

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Light Helps Promote Brain Activity—Even In Blind People

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Photoreceptive ganglion

Photoreceptive ganglion

Researchers at the Boston Brigham and Women’s Hospital and University of Montreal recently published a study in the Journal of Cognitive Neuroscience detailing their findings about how light affects cognition. The most surprising aspect of their experiment is not just that light can promote brain activity, especially when someone is working on a cognitive task, but that this happens even in people who are totally blind.

Light does a lot more than help us see. It gives our brain important situational and environmental information, primarily by indicating whether it’s night or day. You might think that our brains wouldn’t really care about that so much when it comes to performance — I enjoy writing in the dark, for example — but it actually matters a lot. Our biology, behavior, and metabolism take signals from the environment. When you get up in the morning, the first light you switch on often has a jarring effect — the light is what wakes you up, but not simply because it’s bright. It also stimulates responses and activities that humans generally associate with daytime functioning, such as alertness and mood, as well as increased focus and better performance on tasks.