Scientists in Switzerland have figured out how to control brain function using simple flashes of coloured light, and have now effectively induced erections in mice using the same method.
The technique is called optogenetics, and what scientists are doing with it will blow your mind. It all starts with a simple species of pond algae that uses a primitive organelle called an eye spot to respond to sources of light for photosynthesis. A particular type of light-sensitive protein inside the eye spot responds to blue light by moving positively charged ions across the eye spot membrane, and this causes the voltage of the eye spot to change.
Scientists figured out that this process could be replicated in neurons in the brain, so they synthesised the fragment of pond algae DNA that encodes for this blue light-receptive protein, and using a harmless virus, inserted the genes into the specific types of mouse and rat neurons.
The rodent neurons expressed the genes, and their neural membranes soon became covered in the light-responsive protein. When the researchers shone a blue light, the proteins activated, just like they did in the pond algae. When the blue light was turned off, the neurons instantly deactivated.
Why is this so cool? Well, our brains contain thousands, if not tens of thousands, of different types of neurons, each one with a distinct shape, molecular composition, and function. Using optogenetics, scientists are now able to manipulate the behaviour of one specific type of neuron without affecting the activity of those around it. If you're still confused, you can watch the video below for a really clear explanation of the whole process.
So far, optogenetics has only been used on mice and rats, but it's opened up an intriguing possibility for humans… as a potential new sex aid that improves penis function.
The part of the penis in question is the corpus cavernosum, which is the region that gets filled up with blood to facilitate an erection. That's if everything goes to plan. There can be lots of reasons for why the muscles in the corpus cavernosum can fail to relax and let the blood flow through it - you're nervous, depressed, low on testosterone, and so on.
And then even if you manage to get an erection thanks to a cooperating corpus cavernosum, you risk losing it again, thanks to a defective enzyme called cGMP, which traffics the blood flow in and out of the penis. " Viagra slows down that degradation, allowing you to maintain an erection, but it doesn't actually induce an erection without sexual stimuli," says Jason Koebler at Motherboard. "Optogenetics, on the other hand, can be used to trigger erections without any other stimulus."
This week, a team led by bioengineer Martin Fussenegger, from the Swiss Federal Institute of Technology, published a paper in Angewandte Chemie describing the technique they used to control erections in rats using optogenetics.
"He calls it an 'erectile optogenetic stimulator,' and it's quite simple, once you get past the gene-therapy part of it," says Koebler. "Shine a blue light (a Philips goLITE BLU, designed to treat seasonal affective disorder, if you must know) on a rat dick, cause dick to get hard."
All Fussenegger's team had to do was insert the light-sensitive protein DNA into the rats' corpa cavernosa to make them respond to blue light within 55 seconds of exposure. The DNA worked perfectly in relaxing the corpa cavernosa muscles to facilitate blood flow, and the scientists report being able to induce all the erections and ejaculations they wanted, even without a single lady rat in the room. When coupled with Viagra, the technique worked even better.
"Current treatment strategies focus either on restoring erection-promoting pathways or maintaining an established erection, but fail to provide a trigger-inducible erection on demand," the team wrote in the paper. "EROS decouples penile erection from physiological control, bypasses the causes for erectile dysfunction, and providers trigger-inducible erection on demand by simple illumination with a portable commercial light-therapy device."
Will we see this used on humans any time soon? Doubtful, but don't rule it out just yet. The technique used to insert the DNA is the same as that being used in human gene therapy trials, so that part at least has experimental precedence in human, not just animal, models. We just have to figure out the ethics of manipulating human functions using a little blue light.