Optogenetics: Turning On Our Brain Like a Light Switch

By Mandy Wintink

Science can baffle even scientists with its incredible technological power. Imagine being able to control your own brain by simply shining a light into it. All of a sudden you might feel particularly sexual or defensive or aggressive or creative or loving. This may not be possible with humans YET but some of that has been demonstrated in laboratory animals using a technique called “optogenetics”, which was the buzz word at dinners, coffee breaks, and lectures that I was at last week at the Society for Neuroscience Annual Meeting.  

Optogenetics is a technique that allows researchers to very discretely control activity within single brain cells of living brain tissue. “Opto” actually comes from the Latin opto meaning “choose”. At first I mistakenly thought it referred to “optics”, as in light because of how the technology works. The technology involves inserting a light-sensitive probe into cells that can later be activated or silenced by shinning light on those same cells. The probe serves to inject cells with one of several rhodopsins (genes that code for proteins that direct response to light). You may remembering hearing about “rhodopsin” in our human retina. Same idea although in this context rhodopsin is typically taken from photo-sensitive algae. 

The beauty of this technique, from a purely scientific perspective, is the ease at which we can manipulate the system and its behaviour. One lecture I attended was particularly interesting because the researcher showed an animal that in one moment was naturally moving around its cage and then with the flip of a switch (and shinning of the light) the animal instantly started mounting its cagemate. Then, with another flip of a switch, and light shone onto an adjacent area of the brain not far off (i.e., regions of the hypothalamus), the animal quickly changed from mounting into an aggressive attacker.

I have to admit, watching this on video made me quite sympathetic to the poor other mouse who was privy to these sudden changes in behaviour, first being mounted then being attacked in an unnaturally fast manner. I can only imagine that there is a separate animal model of anxiety developing in the innocent bystander mouse! When I was telling someone else about this study (and how I felt bad for the bystander mouse), the person asked “but don’t you also feel bad for the experimental mouse that’s behaviour was being manipulated?”  In fact, the truth is I was less concerned about the mating-attacking mouse because he likely didn’t know any difference. To him, he was probably simply responding to a very real urge to “mount!” then “attack!” as directed by the brain. But for this mouse, the animal who was enduring these sudden changes in behaviour, it may not be that much different than if the instinct emerged naturally on its own. He may not be any more or less in control than before and rather, simply respond to what his brain tells him to do. Reminds me of a talk I also saw by the lawyer, philosopher, neuroscientist, Nita Farahany (written about here).

But alas, it begs the question that others have asked before (e.g., Daniel Gilbert in his TED talk on Happiness). If you were given the opportunity to optogenetically treat yourself for say, simulate dopamine to reduce symptoms of Parkinson’s disease, would you? Or activate happiness to treat depression, would you? Or erase a traumatic memory to ease PTSD, would you?  There is a line there somewhere that we each have in terms of what we would and would not do. Optogenetics may seem exciting (or scary) but perhaps it is not that much different that the “optoreality” we exist under. We are opting for experiences each day with the foods that we eat (or don’t eat), the behaviours we engage in, the people we hang out with, the climate we live in, the alcohol we drink, cigarettes we do or do not smoke, exercise or mindfulness we do or do not do... Optogenetics may just be a fast-track to health, one faster than pharmaceuticals that doesn’t have to pass through our liver.  Hmmmm.... something to think about, says this Provocateur!

Related TED Talk: