The Matrix is ​​coming! Burying 10,000 micron electrodes to eavesdrop on the brain, Musk's brain machine will be implanted in the human body

There is a complex network in your head - a complex network of 86 billion switches!

Weighs 2 and a half kilograms and consumes only 20W of power, which is equivalent to the energy consumption of a light bulb.

However, it has created infinite miracles in bioelectronics!

The brain is an electronic organ?

The core of brain research is the application of sensors technology.

Whether we are familiar with scalp electrodes, magnetic resonance imaging, or newly pioneered methods such as implanted chips, we are all trying to explore this mysterious organ.

Recently, Imec, a Belgian nanodigital research institute, has pioneered the Neuropixels detector, which is a new probe to observe the living brain at the neuronal level.

The first-generation Neuropixels detector alone has been delivered to about 650 laboratories around the world. At the same time, Imec also created the OpenScope shared brain observatory to provide open source data to brain researchers around the world.

This is a globally shared neuroscience research facility, equivalent to CERN’s particle accelerator for shared high-energy physics research.

Neuropixel, a new technology for observing brain activity. Its function is similar to imaging, however, it records electric fields instead of light fields.

The collaboration began in 2010 with a conversation between engineer Barun Dutta and neuroscientist Timothy D. Harris .

Dutta works at Imec, where he uses state-of-the-art semiconductor manufacturing equipment; Harris works at HHMI (Howard Hughes Medical Institute), where he is a senior neuroscientist.

Dutta brings his knowledge of semiconductors to the field of neuroscience

"We need to study local neural circuits in a freely moving animal, Record the spikes of each neuron," Harris said.

Led by Dutta and Harris, a research team with multidisciplinary backgrounds was formed, including engineers, neuroscientists, software designers and other personnel.

Scientists are exploring how to use advanced microelectronics to invent a new sensor that can simultaneously monitor the electrical conversations between thousands of neurons in any small part of brain tissue.

The system invented by the scientists is named Neuropixels. "Think of us as the Intel of neuroscience," Dutta said. "We provide the chips, and then laboratories around the world use them to write code and do experiments." .

It’s not easy to build a digital probe that is long enough to reach any part of the brain organ, but small enough not to damage delicate tissue on the way in.

In fact, the brain is as elastic as yogurt.

Therefore, scientists need to keep the insertion straight but also allow it to bend inside the shaking brain so that it does not damage neighboring brain cells for a long time.

As the brain guides the body through complex behaviors, detectors need to be durable enough to stay in place and record reliably for weeks or even months.

Neuropixels pushes neuroscience to a higher stage, provides better treatments for brain diseases such as epilepsy and Parkinson's, and paves the way for future brain-computer interfaces.

Back in the 1950s, researchers used a primitive electronic sensor to identify neuronal deactivation in Parkinson's disease patients.

After 70 years of development, with the microelectronics revolution, all components of the brain probe have been miniaturized, and brain electronic sensing technology has made great progress.

In 2021, the system will be upgraded to version 2.0. Compared with the initial version 4 years ago, the number of sensors has been increased by an order of magnitude.

Now, version 3.0 is in the early development stage.

Scientists believe that neuropixels will grow exponentially in accordance with Moore's Law.

And this is just the beginning.

Neuropice2.0!

Biology experts who study the brain suggest that experimenters use gold or platinum for electrodes and then use organometallic polymers for the handles.

However, these materials are not compatible with advanced CMOS manufacturing processes. Therefore, the experimenters conducted some research and did a lot of engineering design. Ultimately, Silke

Musa invented titanium nitride, an extremely strong electrical ceramic that is compatible with CMOS and animal brains.

Also, the material is also porous, which gives it low impedance. Low impedance is very helpful for getting current and clearing the signal without heating nearby cells, creating noise that corrupts the data.

Thanks to extensive materials science research and some related techniques in microelectromechanical systems (MEMS), researchers are now able to control the internal stresses generated during the deposition and etching of silicon rods and titanium nitride electrodes.

In this way, even though the silicon rods are only 23 microns (microns) thick, they can always maintain an almost perfectly straight line.

Each probe consists of four parallel handles, each of which is equipped with 1,280 electrodes. Within 1 centimeter, the probe is long enough to reach anywhere in the mouse brain.

Mouse studies published in 2021 showed that the Neuropice 2.0 device could collect data from the same neurons for six consecutive months while the rodents lived their normal lives.

The elasticity difference between the CMOS-compatible handle and the brain tissue is huge. This leads to a problem: when the probe is in the brain, it inevitably follows the movement of the brain. How should individual neurons be tracked while moving.

We all know that neurons are 20 to 100 microns in size, and each electrode is 15 microns in diameter, which is small enough to record the isolated activity of a single neuron.

#But after six months of jostling activity, the entire probe may have moved 500 microns within the brain. During this time, any given pixel may see several neurons coming and going.

(Currently the most common neural recording device)

In addition, the 1,280 electrodes on each stem are individually addressable, four The parallel stems give researchers effective 2D readings, which are very similar to images taken by a CMOS camera.

This similarity made the researchers realize that the problem of neuron displacement relative to pixels is very similar to that of the IS system. Like shaking a camera while filming, the neurons in an area of ​​the brain are correlated with their electrical properties.

Researchers can use existing methods to solve the camera shake problem to solve the problem of detection head shaking. With the application of stabilization software, researchers can use automatic correction functions when neural circuits move at will.

Version 2.0 reduces the circuit board located outside the skull, which controls the implanted probe and outputs digital data, to the size of a thumb.

In this way, one circuit board and base can hold two probes, and each probe extends four small handles, with a total of 10,240 recordable electrodes.

The researchers wrote a control program to achieve a high sampling rate and capture a large amount of data. This is 500 times what CMOS imaging chips can usually record. But currently the device can't capture the activity of every neuron it touches.

Continued advances in computer technology will further alleviate existing bandwidth limitations within the next few generations.

In just four years, researchers have almost doubled the density of pixels, doubled the number of pixels that can be recorded simultaneously, and increased the overall number of pixels by more than ten times. The size of external electronic equipment has not increased but decreased, shrinking by half.

The next generation version 3.0 is also under development and will be released around 2025, maintaining a release rhythm of every four years. In version 3.0, the researchers expect that the number of pixels will jump again, allowing monitoring of approximately 50,000 to 100,000 neurons.

Meanwhile, the team plans to continue adding detectors and triple or quadruple the output bandwidth and reduce the base bandwidth by a factor of two.

(The first Neuropion device. There are 966 electrodes on the handle.)

Frankenstein opened the skull, the first human brain machine

In order to advance scientific research, many Frankensteins have conducted experiments on their own bodies. In 2014, Phil Kennedy, a neuroscientist in his late 70s in the United States, sawed open his own skull and implanted electrodes into his brain.

At that time, because he could not find experimental subjects and research funds were about to dry up, Kennedy decided to operate on his own brain. The brain surgery lasted for 11 and a half hours, and it actually didn't go very smoothly.

Kennedy lost the ability to speak when he woke up. He did this to create a speech decoder that would allow patients who cannot speak to "speak" again through a brain-computer interface.

Previously, Phil Kennedy had been researching in this field for nearly 30 years. He was a well-known neuroscientist and was called the "father of cyborgs" by many.

The invasive brain-computer interface he developed in the 1990s allowed a severely paralyzed person to learn to use his brain to control the computer cursor to type, so that others could "hear" his voice.

There are countless studies on brain-computer interfaces, and the most exciting and exciting one is Neuarlink’s research. Just in August 2020, Musk announced Neuarlink's major breakthrough at the press conference.

This time, the magical device created by Musk is only the size of a coin. It is surgically implanted in the skull and can be used for a whole day when fully charged. Musk said that the most essential issue of brain-computer interface is "wiring".

At the scene, Musk showed off a healthy piglet that had been implanted with a Neuralink device for two months.

The main purpose of the experiment is that after the chip is implanted, the brain activity of the pig can be visually seen. When the demonstrator touches its nose, the pig's nerves start to get excited. Under the action of 1024 electrodes connected to the device, the radio wave signals in its brain are clearly visible.

Also in April 2021, Neuralink once again made new progress. A monkey can play table tennis with its thoughts. In the experiment, Pager, a 9-year-old rhesus monkey, had two N1 Links implanted in his head, and the staff tempted him to play games with banana milkshake. As brain-computer interface technology continues to advance, paralyzed patients will be able to operate smartphones with their thoughts faster than with their fingers.

Musk said last year that brain-computer interfaces would be used on humans this year. Brain-computer interfaces are promising in the future. ######References:######https://spectrum.ieee.org/brain-implanthttps://36kr.com/p/1722359709697######https://www. sohu.com/a/193608196_426424######https://www.imec-int.com/enhttps://www.hhmi.org/###

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