The gospel of the blind.
Editor’s note: This article is from WeChat public account “qubit” (ID :QbitAI), author of chestnut fish sheep.
The road idiot was saved.
The scientists at the University of Pennsylvania, through the brain-computer interface, gave rats a kind of nerve stimulation to help them find the right direction.
In the original, rats swimming in the water maze could not see the destination hidden under the water. But after receiving the stimulus, the rat will regard this as a new sense, learn to use it and smoothly swim to the designated location.
Note that the rat has never received a similar stimulus before the experiment, but after using it, it is accustomed to such a setting, using the “sixth sense”, just as skilled as using vision.
The eye does not see the target position and can reach it accurately within 5 seconds.
Under obstacles, you won’t be confused, decisively bypass, and easily find the target:
As if the brain was implanted with the Map App as silky.
What’s more, the strategies for rats to explore the world will change in different stimuli: Zigzag and Ring, each with Each advantage.
In other words, when the “sensor” in the body changes, the animal’s movement strategy will also be adjusted.
Someday, visually impaired friends can embrace new senses and go out more easily and go to new places.
This wonderful study has just been featured in the top journal PNAS (Proc.).
How is the sixth sense created?
The scientists used a name called ICMS (transcranial microcurrent stimulation) stimulation.
ICMS activates about ten neurons at a time. That is to say, instead of activating the entire brain area, it transmits information to a specific area. Compared to methods such as direct current stimulation, ICMS is more accurate and more targeted.
Scientists implanted a pair of cerebral cortical bipolar stimulation electrodes into the brain of adult rats.
The specific test experiment is the classic Morris water maze. The rat is placed in the center of the pool, and there is only one hidden underwater platform in the pool for standing.
For this classic experiment, the scientists made a small change to change the position of the platform to random. That is to say, the rat can not only see the platform, but also can not find the position of the platform by memory. The only clue that can be relied on is The perception caused by ICMS.
However, it is not enough to just provide a stimulus to the brain. To create new senses, the brain must learn to use use stimuli to deal with external signals like the natural visual and olfactory.
To achieve this goal, rats must be trained.
In the experiment, the camera monitors the swimming path of the rat at 12 frames per second. As long as the forward direction of the rat is within a certain range of target direction (eg <15°, 45°, 90°), give it a stimulus.
like thisSample:
△ Pre-training experiments in rats
In a single frame of video surveillance, you can see an angle between target direction and rat forward direction.
When this angle is less than the set range (can be 15°, 45°, 90°, etc.), judge the correct direction of advancement, the wireless transmitter will exceed the threshold intensity, The pulse current is transmitted at a frequency of 100 Hz. When the angle is outside the range, determine the rat’s deviation, it will not transmit the stimulation signal.
There was a nerve stimulation at first, and the rat was still stunned. He didn’t know what he was irritated and didn’t know how to use it. It took 23 seconds to find the green dot:
But like this, after 100 to 200 training, the rats learned to deal with the stimulus information, the sense of direction increased rapidly, and it was effortless to go straight to the target. 5 seconds:
△Related rats
The results of the experiment also show that if the baseline is can see the platform position (green dot), the stimulus range is 15°< /strong>The average distance traveled by the rat to the end point, very close to the baseline level when using vision.
In other words, after only one or two hundred training sessions, the rat used the “sixth sense” of the day after tomorrow, which is as skilled as using natural vision.
However, if the stimulation range is further reduced to less than 5°, the effect will be worse.
In addition, setting different stimulation ranges, the strategy for exploring the world learned by rats is also different:
If the setting is within 90° of the stimulus, the rat is accustomed to the ring movement.
This way, you can quickly try all directions to find the right direction.
If the setting deviates from within 45° or even within 15°, the rat grasps the way forward Zigzag.
Probably because the stimulus received in this case is more accurate, and you don’t need to use the circle to try every direction.
More interesting phenomenon is that when a rat gains a “sixth sense” according to the normal training process, change the routine: in turn in the rat Give stimulation when you are biased, and don’t give stimulation when you are in the right direction.
This way again, the rat adapts to the new sensor and still gets the “sixth sense” that is as easy to use as vision. Did not fall into chaos because of the stimulating routine:
Save the road idiot, it is the gospel of the blind
Of course, such a high-quality “sixth sense” is not just for saving the road idiot.
Now, the new sense of the mouse is already comparable to vision, and if humans can unlock similar achievements, visually impaired will go out and not be like before. It’s so difficult.
Before this, there are also many laboratories that have studied how to help visually impaired partners navigate in unfamiliar environments. The prominent MIT CSAIL lab is one of them:
In 2017, the team published a set of wearable devices. Inside, there is a depth camera to detect obstacles; a tactile vibration belt, and a refreshable braille display to receive the camera The news was passed on to the visually impaired.
After wearing it, the visually impaired can walk out of the maze without a cane.
In addition, the device can also detect some specific objects, such as empty chairs, and guide the friends to go over and sit down:
At this time, if you have a cane, you can use it to speed up the process.
However, this system also requires manually reading Braille.
In contrast, if humansWith the help of the brain-computer interface, with new senses, navigation may become smoother.
Benda results, many Chinese authors
The author of the paper is a 12-person team from the University of Pennsylvania, which has neuroscientists and experts in the Department of Electrical and Systems Engineering.
One work is Andrew G. Richardson, an assistant professor at Penn. Including him, the team has seven small partners, all from the Department of Neurosurgery.
The other five partners are from the Department of Power Systems Engineering, three of whom are Chinese:
Liu Xilin, graduated from Harbin Institute of Technology, graduated from Penn University in 2017, and now works as a senior design engineer at Qualcomm.
Han Hao, graduated from Huazhong University of Science and Technology, and started to study at Penn in 2017. Zhang Yulin graduated from Tsinghua University with a postgraduate degree in Penn in 2016. In the same year, she returned to Tsinghua University to teach in the Department of Electronic Engineering. He is currently an associate professor and doctoral supervisor at the Tsinghua Institute of Circuits and Systems.
Transportation Gate
Thesis address:
http://sci-hub.tw/https://www.pnas.org/content/116/35/17509.short?rss=1