Sci-fi tales like "The Matrix" and "Ready Player One" depict immersive virtual-reality settings that simulate every sensation — sight, sound, touch, taste, and smell — as if it's really happening. Like many futuristic concepts, however, this kind of technology wouldn't just be handy for hyper-realistic video games; it could actually change the lives of people with disabilities, helping them take in the world around them in ways never before possible. In April, researchers from the University of California Berkeley announced an essential first step toward this brave new world: they've created a holographic brain device that can simulate false sensations.
Light Me Up
The device works via a concept called optogenetics, which involves placing genes that produce light-responsive proteins into specific cells in the body. That way, researchers can use specially targeted light to alter the cells' behavior. The Berkeley team performed this genetic engineering in the brains of live mice — specifically, on 2,000 to 3,000 neurons in the somatosensory cortex, which is responsible for processing sensations like touch, pain, and temperature. Once the engineering was complete, it just took a precise burst of light to create a spike of activity in the targeted neuron.
Of course, neurons are very, very small — smaller than the width of a human hair. To target individual cells with light, you need a super-precise focus. For that, they used something called computer-generated holography. As the name implies, this technique bends and focuses light to create a three-dimensional pattern — but instead of making a hologram of Tupac, the pattern they created was designed to pinpoint each of up to 50 neurons in one three-dimensional chunk of brain. While one laser pulse might target a bunch of neurons at once, this precision technique was able to target only the neurons the researchers wanted to trigger. Even better, they could do this at up to 300 times a second with many different sets of neurons.
See How Deep the Mouse Hole Goes
The team was able to use these light patterns to mimic real patterns of activity in the brains of these mice, ostensibly making those mice feel whatever sensation the researchers wanted them to feel. They tested the prototype in the touch, vision, and motor areas of mouse brains as the mice walked on a treadmill with their heads kept still. That unfortunately means that they weren't able to see actual behavior changes; just changes in their brain activity.
The next step is to train the mice in such a way that the researchers can observe any changes in their behavior after the treatment. A few years ago, this type of device would have been unthinkable for human applications, since such techniques weren't considered suitable for use in humans. But times change, and optogenetics is already undergoing its first human trials.
Eventually, the team hopes to create a device that can constantly read activity in the brain and use that to decide which neurons to activate in order to simulate a desired brain response. That could help control a prosthetic limb or replace lost sensations after nerve damage, for example.
"If you can read and write the language of the brain, you can speak to it in its own language and it can interpret the message much better," said Alan Mardinly, a postdoctoral fellow and co-author on the report, in a statement. "This is one of the first steps in a long road to develop a technology that could be a virtual brain implant with additional senses or enhanced senses."Source:Web
