What if we had the ability to fool our brain into thinking that we’d experienced something that never happened?
While this may sound far-fetched, neuroscientists at the University of California- Berkeley are developing a technique that could do just that by manipulating electrical activity in the brain.
The technique is called holographic projection and it involves a piece of equipment known as a holographic brain modulator, which uses flashes of light to activate or suppress neurons — or nerve cells — in the brain in a way that mimics real patterns of brain activity. By doing this, you can trick the brain into thinking something it hasn’t felt or sensed before.
Ultimately, the Berkeley team are aiming to be able to simulate patterns of actual brain responses by controlling thousands of neurons at once. This could have a number of useful applications.
For example, they hope that the technique could, one day, be used to control prosthetic limbs, enable paralyzed people to feel, touch or even allow the blind to see by converting the images from a camera lens into real brain activity.
“This has great potential for neural prostheses, since it has the precision needed for the brain to interpret the pattern of activation,” Alan Mardinly, an assistant professor of molecular and cell biology at Berkeley, said in a statement.
“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,” he said. “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.”
But it may also have more profound implications. Such an ability could pave the way for technologies that may enable us to replace painful emotions or insert memories into our minds of things that we never saw.
Mardinly and his colleagues are the authors of a new paper, published in the journal Nature Neuroscience, describing the prototype holographic brain modulator and tests they conducted on mice.
The researchers used the modulator to shine pulses of light through areas of the rodents’ skulls where the beam could reach the brain. Each of these pulses — which were fired 300 times a second — activated up to 50 neurons at once in tiny sections of brain, each containing several thousand neurons.
Before exposing the mice to this light, the team administered the animals with a virus that altered the functioning of their neurons so that the nerve cells would activate when struck by a pulse of light.
“The major advance is the ability to control neurons precisely in space and time,” said Nicolas Pégard, another author of the paper from Berkeley. “In other words, to shoot the very specific sets of neurons you want to activate and do it at the characteristic scale and the speed at which they normally work.”
The team tested the modulator on areas of the brain related to touch, vision and motor skills, as the mice walked on a treadmill with their heads immobilized. While they did not observe any behavioral changes in the mice, they did measure brain activity that was similar to that seen during normal sensory stimulation, indicating that the technique was having some effect.