Feng se Xiao Zhen originated from The Temple of Oufei
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Can you remotely "manipulate" the biological brain without implanting a control device?
A recent study published in the nature sub-journal rushed to the hot search as soon as it was published:
Although the subject of this experiment is not a human but a mouse, many netizens' first reaction after reading it is still "too dangerous" and "a little anti-human":
So, is this really a particularly scary technology?
In fact, this research is mainly through a certain technical means, using special light to illuminate the head of the mouse, turn on its "movement mode" - the old can't help but want to go around.
It can be said that it is a real physical exercise (manual dog head).
And, the technology is truly groundbreaking.
According to Stanford University, this is the first time scientists have successfully controlled the neural circuits of normal organisms at a distance by not invading the brain.
Throughout the process, no implanted devices were implanted and no damage was inflicted on the scalps and skulls of the mice.
At the same time, it is not only a technological exploration, but also has certain application value in the treatment of neurological diseases.
Let's take a closer look.
Using near-infrared light, brain cells are remotely manipulated
In fact, using light to control brain cells is already a relatively mature study.
One of the most typical technologies is optogenetics, which has been named one of the "Top 10 Breakthrough Studies in Biology" by Science in the past decade, and was even once predicted to be a Nobel Prize-level research achievement (awarded the "Nobel Prize Weathervane" Lasker Award).
This technology was also proposed by Stanford University, specifically referring to the introduction of foreign (not naturally occurring) photosensitive protein genes into brain cells, so that brain cells express photosensitive proteins on the cell membrane structure.
Then, by irradiating these cells with a specific wavelength of light, you can control the activation and shutdown of light-sensitive proteins, thereby activating or inhibiting neurons in the brain, achieving the purpose of "controlling brain cells".
BUT, this technology has always had a flaw -
Optical implants must be installed and a fiber optic tie must be inserted into the skull.
This is because optogenetics relies heavily on visible light, and the brain is opaque and cannot be passed through by visible light.
But implanted devices not only cause tissue damage, but also restrict the free movement of organisms, making it difficult to study the neural activity of the brain under the natural behavior of organisms.
In the latest study, the scientists finally managed to remove the implanted device from the mouse's head.
They found a near-infrared light, the near-infrared two-band band of 1000-1700 nm, which maintains high penetration in highly scattered brain tissue.
Without implanting optical devices, how can brain cells be controlled through light signals?
This brings us to a protein called TRPV1 in living organisms, which was awarded to its discoverers last year's Nobel Prize in Physiology or Medicine.
Specifically, it is a capsaicin (something that produces a burning & painful sensation) receptor, that is, an ionic channel protein that reacts to heat and pain, that is, it is very sensitive to heat & pain.
Implant it in a rattlesnake, which can prey on warm-blooded prey in the dark; implanting it in a mouse retinal pyramidal cell gives the mouse the ability to see in the infrared spectrum.
However, when the scientists implanted this heat-sensitive molecule into mouse neurons, they found that it did not work on the thermal signal of near-infrared light because the photothermal signal was still too small.
Implantation here refers to transfecting the target neuron with an adenovirus wrapped in TRPV1, that is, introducing DNA, RNA or protein into the cell.
So they designed a "sensor" molecule called MINDS, specifically designed to absorb and amplify infrared light.
In this way, the principle design of the entire system is completed.
It is hoped to be used to treat neurological disorders
This is followed by further experiments to test whether this theory is feasible.
The scientists first added TRPV1 channels to neurons on one side of the motor cortex of the mouse brain, then injected the MINDS molecule, and finally observed the mice's behavior.
△ Bald mice, making it easier for light to penetrate
They were surprised to find that when the infrared light at 1m above the fence was turned on, mice that were initially only active in a small area immediately began to circle, greatly increasing the range of motion.
The black line represents the mouse trajectory before irradiation, the red line represents the irradiation, and the gray line represents the end of irradiation.
Mice in the control group did not have this response.
That is, the stimulation of the brain motor cells of the mouse by near-infrared light worked.
They also injected the two molecules into the dopamine expression neurons of mice, and two days later, placed an infrared light focusing device in the mouse's Y-shaped maze.
It was found that the mice were "addicted" to infrared light that stimulated dopamine neurons and stayed under the light for the longest time.
△ Different colors represent the time that mice stay, and red is the longest
Well, it worked again.
While motor neurons are located above the brain and dopamine neurons are located at the bottom of the brain, this non-invasive method controlled by near-infrared light is effective for neurons in any area of the brain.
According to Hong Guosong, the corresponding author of the paper, the purpose of this study is mainly to achieve one of the biggest unmet needs in neuroscience through this non-invasive method.
Under free activity (such as social interaction), mice are observed and recorded for the function of specific brain cells and circuits deep in their brains.
Further, this approach also contributes to a better understanding of the human cognitive system.
If this technology eventually matures, it can be used clinically to regulate specific neuronal circuits in the patient's brain and treat some neurological diseases, such as epilepsy.
After carefully reading this study, some netizens proposed that these studies are not only very important research tools and methods for exploring the function of neurons, but also provide an extremely important basis for studying the brain:
Some netizens hope that it can be used in the treatment of more diseases, such as Alzheimer's disease.
The research came from a Chinese team
The study was done in collaboration with Stanford University's Hong Guosong team and a Team of Pu Kan people at Nanyang Technological University in Singapore.
There are two of them, one is Wu Xiang, a doctoral student from Stanford University, and the other is Jiang Yuyan from Nanyang Technological University.
The corresponding author is Hong Guosong, an assistant professor at Stanford University's School of Materials Science and Engineering and the Wu Cai Institute of Neuroscience (renamed by a donation from Mr. and Mrs. Wu Minghua-Cai Chongxin).
He graduated from Peking University with a bachelor's degree, and later received his Ph.D. in chemistry from Stanford University, went to Harvard University for postdoctoral work, and joined Stanford University in 2018, where his current research direction is materials science and neuroscience.
△ Hong Guosong
The co-corresponding author is a Pu Kan-din, associate professor at Nanyang Technological University in Singapore, who previously graduated from East China University of Science and Technology with a bachelor's degree, received a master's degree from Fudan University, received a doctorate from the National University of Singapore, and did postdoctoral work at Stanford University.
His research interests are polymer materials and biomaterials, including nanotechnology, and the two corresponding authors have cited more than 20,000 papers.
△ Pu Kan descent
So, in what directions would you like this research to be applied?