You control your urges for violence and sex using a tiny tangle of neurons located in a very ancient part of your brain. Now it turns out that this knot of nerves, located in the hypothalamus, can be controlled with a new gene therapy technique that uses flashes of light. What this means is that scientists may be on the verge of turning us into mindless soldiers, unable to stop ourselves from attacking anyone or anything that gets in our way. But this discovery is also the perfect shutdown command for people who can't control their violent urges. Either way you look at it, in ten years, we could be manipulating people's most primal urges with beams of light.
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The light that controls your urges
A group of neuroscientists in California and Seattle published a paper today in Nature, showing how they used bursts of light to stimulate the "hypothalamic attack area" in mouse brains. Basically, they use light to change the behavior of neurons in the mouse hypothalamus in a technique called "optogenetics" that combines optics with genetic manipulation. After undergoing optogenetic stimulation, their mice would attack anything introduced into a cage with them - other mice, and even inanimate objects like a glove.
What the scientists discovered, however, was that the attack area of the brain overlapped a lot with the parts that govern sexual desire. Electrical activity in the brain of a mouse that's about to attack looks very similar to brain activity in a mouse that's about to mate. And with just a bit of tweaking, the scientists could convert that attack pattern into a mating pattern - thus shutting down an attack as quickly as they started it. They also found that mice who were already mating were largely immune to having their attack areas stimulated with light. You couldn't easily turn a mating mouse into a fighting one.
The researchers conclude:
Our functional manipulations did not perturb mating behaviour. One possibility is that these female-activated neurons serve to inhibit aggression during mating. Consistent with this idea, many male-activated units were actively inhibited by females, and a higher intensity of illumination was required to evoke attack towards a female during mating encounters.
Only male mice were tested in this study, so the "female activated neurons" refer to the regions involved in sexual desire. (Presumably our mice were also heterosexual.)
Would it work on humans?
Because these optogenetic studies focused on the hypothalamus, an ancient part of the brain that humans share with other mammals, it's likely that scientists will seek a way to apply what they've learned to humans.
In a commentary article in Nature, neuroscientist Clifford B. Saper acknowledges directly that one use for this technique would be behavior conditioning in people. He writes:
In A Clockwork Orange, social engineers used Pavlovian conditioning of the protagonist to induce an aversion to both sex and violence. Could - and should - the behaviour of sex offenders or violent criminals be similarly controlled by genetic therapy? . . . With this information in hand, researchers could potentially design vectors to introduce foreign ion channels only in a specific group of neurons - a way to differentially modify sexual or violent behaviours.
Controlling people who are violent sounds like a good use of the biotech here, but not when you consider that it could just as easily be used to force people to become violent or have sex against their wills. This is the ultimate soldier drug. The ultimate sexual repression drug. And the scariest part is that it seems to work.
The one ray of hope here is that this optogenetic technique doesn't always work. Mice having sex could not be induced to become violent. Their desire to mate overrode their desire to fight. It's possible that the old "love conquers all" trope may be true at a neurological level.