Augmented and virtual reality (VR) are growing trends in technology, due in part to the success of hardware like the Oculus Rift. We have discussed a fictional virtual-reality system that allowed someone to experience the world through the eyes of animals. However, these fictional simulations kept running up against limitations. No matter how good the hardware is, it’s still screens, speakers, and controllers sitting on top of the human body, and limited by our sensory capacity.
But what if we could take it a step further, and bypass our sensory organs? Science fiction is filled with virtual reality systems that completely immerse a user in the virtual world. Not only are any actions in this world completely driven by thought, but all sensation is delivered directly to the brain. If such a system existed, it would be theoretically possible to make someone experience things that are physically impossible for a normal human body. The question remains, is such an interface possible? The answer is probably, eventually.
Again, a crucial component of such a system would be scanning the brain in extreme detail, and being able to interpret those signals. While that is a very active area of technological development, let’s ignore it for now. The more interesting, potentially sinister, and potentially wonderful aspect of this technology is precision brain stimulation. Scientists already have a number of ways to do this. Some methods are only used in basic research so far or mostly on animals, while others have reached clinical effectiveness.
Transcranial magnetic stimulation (TMS) is a real success story in the field of brain stimulation. Magnetic fields generated outside the body are precisely positioned near the head, generating electrical currents in specific brain areas. This can temporarily enhance or suppress the activity in certain brain areas. The fact that the effects are temporary is a major safety selling point. However repeated exposure does have long term effects. This is actually good, as it’s been used for several years as a treatment for major depression. Targeting other areas of the brain is being investigated for treating other neurological conditions.
While that is all very interesting, precision stimulation is needed for a true VR experience. Fortunately, some researchers from the University of Washington are already working on that. What they have been working on is a brain-to-brain interface. One participant has her brain scanned with a set of noninvasive EEG electrodes, then custom software analyzes that pattern of brain activity looking for a specific signal. Once the signal is detected, it triggers a precisely placed magnetic field, stimulating the brain of a second person and causing her to move their finger involuntarily. Using this system, three pairs of subjects were able to cooperatively play a very basic computer game. The participant being scanned could see the game and think about triggering the action, while the other subject could have her brain stimulated but couldn’t see the game. It’s not much right now, but the goal is for full brain to brain communication. For that to work, a better understanding of the brain would be required, as well as multiple or adjustable magnetic fields for stimulating the brain in more complex ways (If you want to know what it feels like to have your brain partially controlled, check out my interview with one of the researchers from 2013.).
If a brain-to-brain interface were fully realized, it would take a simple software change to make it a fully immersive VR experience. The game/virtual environment would be triggering things in the brain, rather than another person. However, it’s unclear whether TMS has any limitations in terms of precision. Ideally, you would want something as precise as activating or deactivating individual neurons. That is exactly what optogenetics can do.
Optogenetics is an extremely popular neuroscience research tool, but has only been used in animals. The genes for light-sensitive membrane channel proteins are taken from other organisms, like algae and bacteria, and inserted into neurons. Once the neurons express these genes, they become sensitive to light, and multiple proteins make it possible to turn neurons on and off. With the variety of proteins available, different sets of neurons can be made sensitive to different colors of light. It’s unclear whether this technology will ever jump from research into clinical applications, but money is being spent to find even more light-sensitive proteins that can be used.
Of course, the obvious limitation to this system is the fact that the brain and skull are opaque. When optogenetics is used in a subject, like a mouse, it involves implanting fiber-optic cables into the brain. Probably a little too extreme for most gamers to go through. So what we need is the precision of optogenetics with the non-invasiveness of TMS. As recently as March of 2015, MIT researchers reported on their research into brain stimulation involving magnetic nanoparticles. This still involved genetically engineering neurons, but instead of inserting light-sensitive channels, they inserted capsaicin receptors. Capsaicin is what makes spicy food spicy, but the receptors also respond to physical heat.
When tiny iron oxide nanoparticles are injected into the brain, they actually stay pretty much where they’ve been placed. An alternating magnetic field causes these particles to wiggle and generate heat, thus triggering the capsaicin receptors and the neuron as a whole. In theory, the precision of an advanced TMS system could be greatly increased with some specific injections of such nanoparticles. This would allow for highly controllable stimulation of various brain areas. If focused in on the sensory areas of the brain, it could lead to a fully immersive virtual reality experience that would be otherwise impossible. Sure it would involve extensive gene therapy and some brain injections.
So, how far would you be willing to go for full immersion?