To state that the brain is a very complicated organ, it would be carrying wood into the forest. A new American study, however, reminds us it again in a fresh way. At the University of California, they developed a technology called brain holography that can control the activity of large populations of neurons with great fidelity. It could serve to create artificial sensations or even memories.
Today’s medicine in influencing brain processes usually relies on chemical substances. Some experimental methods such as deep brain stimulation have already remembered that electricity can also have a remarkable effect. Then there is the third, and by far the youngest method called optogenetics.
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It combines optics and genetics. Although the field does not have to be technically focused on the brain, it brings the most interesting results. Typically, an optogenetic approach first requires genetic interference in an organism that makes the tissue more transparent and increases the sensitivity of cells to a specific light signal. Then, by targeting light signals – typically directed to brain cells or neurons – they can activate different cells and thus “speak” to the brain.
Optogenetics as such has not been the world for two decades, the first major steps have only begun to do after 2010. Now, however, the California invention has made a great leap forward.
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Researchers have created a multi-photon holographic method to activate – or suppress activity – of the entire set of neurons at one time. Optogenetic experiments have so far operated with the possibility of affecting one neuron or a few neurons at a time. The new device in the form of a precision laser projector is not only able to activate up to 50 specific brain cells of different height (in 3D space), but can also activate them in milliseconds.
In order for the widget to work, it must have prepared ground – this in practice still means the genetic modification of the organism, in the current study of the mouse. The brain cells of the animal can be hit by up to fifty times per second after editing – simulating the same frequency as normal brain activity.
Scientists have already tested the projection system in simulation of touch, vision, and motoring. The mouse, which was fastened to the waist (still had a fixed head so the laser could activate the parts of the brain), the method by shooting into dozens of neurons simulated the desired sensory stimulus. This indicates at least the scans of the brain activity gained during the experiment.
The ultimate goal of researchers is to improve the method so that up to several thousand neurons can interact. This would already give a chance to simulate more complex feelings and people. The authors primarily aim at the possibility of a similar method of creating the appearance of a touch in people using artificial limbs.
Still at the beginning
Even more visually, it might be possible to simulate the sight itself. And once, a similar method could also serve to create artificial reality, or artificial memories. But we are talking about a very distant and very hypothetical future.
Meanwhile, this advanced optogenetic projection has a whole range of its “but”. The first possible problem stems from problematic testing of conclusions on anything smarter than mice. Optogenetic attempts on humans will be very long, perhaps forever, forbidden by nature. So there’s still a chance that the mouse test results are not as promising as scientists think.
From the practical problems arising from the application, there is also a need for a direct view of the laser on the brain tissue. Even if future generations would rely on having the skulls transparent (or rather developed miniaturized lasers as implants), it seems to be clear that the method is still far from being tangible.
The prospective chance to affect thousands of neurons also sounds very solid – but let’s recall that the brain contains between 50 and 100 billion neurons. So the future version of California technology will not have an unlimited influence. Yet similar progress in brain study is significant. For the first time in history, scientists have a chance to study the syntax of individual neurons and neural networks. The language that makes our minds create thoughts and feelings.
Ophtogenetics is perhaps only at the beginning – but there is no obvious problem in understanding why its potential evokes memories of the first years of DNA cognition.