A Team Of American Researchers Has Developed A System That Uses Dozens Of Silicon Microchips To Record And Transmits Brain Activity To A Computer.

Neurocrines, Dozens of microchips scattered across the brain’s cortical surface may help researchers monitor the activity of thousands of neurons simultaneously.

Called Neurograins, each about the size of a grain of salt, these chips are designed to scatter over the brain’s surface or across its tissue to send nerve signals from areas relative to what other brain implants might do. Collect more from the brain.

“Arto Normico, the lead author of the paper and neuroscientist at Brown University who led the making of the Neurogrins, says:”

Each of these beads contains enough microelectronics that, when embedded in nerve tissue, can record neural activity on the one hand and transmit it to the outside world on the other.

It is known as a kind of brain-computer interface. Neurocrines are described in an article in the journal Nature Electronics.

Normico, along with other Brown University researchers and colleagues from the University of Baylor, the University of California, San Diego, and Qualcomm, began work on the Norwegians four years ago with funding from the US Defense Advanced Research Projects Agency (DARPA). So far, they have only tested Neurocrines on rodents but hope that their prototype will pave the way for human studies.

In addition to recording brain activity, Neurocrines can also stimulate neurons with small electrical pulses, providing an attractive way to study the treatment of brain disorders such as epilepsy and Parkinson’s disease or to restore lost brain function after injury.

The researchers implanted their system in rats and performed a craniotomy (cutting a part of the skull) to place 48 Neurocrines on the cerebral cortex (outer layer of the brain).

They positioned the microchips to cover most of the motor and sensory area. A finger-sized thin layer attached to the scalp acted as an external communication centre, receiving signals from the Neurogrins, processing them, and charging the chips wirelessly.

_{Several silicon microchips have known as Neurocrines}

The researchers tested their system while the animals were under anaesthesia and found that Neurocrines could record spontaneous cortical activity in anaesthetised mice. However, the quality of the signals was not as good as the signals from commercial chips found in most brain-computer interface research.

These relationships have been evolving since the 1970s. In recent years have helped a few paralysed patients control tablet devices, type something on a computer while thinking about something, or move a robotic limb or cursor on a screen…

These systems for people with brain and spinal cord injuries can eventually restore communication and movement and help them live more independently. But for now, they are not very practical.

Most of them have unpleasant structures and can not be used outside the research laboratory. People with brain implants are limited in what they can do because of the relatively small number of neurons that the implant can record at the same time.

The most common brain chip used is the Utah Array, a layer of 100 silicone needles, each with an electrode at its end that attaches to the brain tissue.

One of these arrays is the size of Abraham Lincoln on a US coin and can record the activity of several hundred neurons around it. But many of the brain functions that researchers are interested in (such as memory, language, and decision making) involve networks of neurons scattered throughout the brain.

“To understand how the brain works, you need to study them at the systems level,” says Chantel Pratt, an associate professor of psychology at the University of Washington. She is not involved in the Neurogrens project.

 Pratt’s research is on non-invasive brain-computer relationships that cover the head instead of implanted in the brain.

The ability to record the activity of more neurons could enable more precise motor control and extend what is now possible with brain-assisted control devices. Researchers can also use them in animals to understand how different brain areas communicate with each other. “In terms of how the brain works, the whole is more important than the sum of the components,” says Pratt.

Florian Sulzbacher, co-founder and chairman of Utah Array, Blackrock Neurotech, says the extensive neural implant system may not be necessary for many short-term applications, such as activating essential motor functions or using a computer. However, more forward-looking applications, such as memory retrieval or cognition, certainly require more complex organisation. He says:

The superior technology can record as many neurons throughout the brain, from the surface and the depth. Do you need all this complexity right now? Probably not. But the more information we have about understanding the brain and future applications, the better.

Smaller sensors can also mean minor damage to the brain.

Current arrays, even if small, can cause inflammation and scar tissue at the implant site. “Usually, the smaller you make something, the less likely it is to be recognised by the immune system as a foreign body,” says Solzbacher, who did not participate in Brown’s study.

When the body recognises a foreign object, such as a chip, it tries to destroy it or cover it with wound tissue. But while smaller implants may be better, they are not necessarily free of defects. Even tiny implants can stimulate the immune response; Therefore, Neurocrines should be made of living compatible tissue items.

One of the main challenges in making brain implants is creating and implanting a permanent implant that avoids the risk of needing replacement surgery. Current arrays last about six years, but many of them fail much sooner due to the formation of wound tissue around them.

If Neurocrines are the solution, there is still the question of how to get them into the brain.

In their rodent experiments, Brown researchers removed a large part of the skull of mice that would not be desirable in humans for obvious reasons.

The currently implanted arrays require a hole to be made in the patient’s head, while Brown’s group intends to avoid invasive brain surgery altogether. To do this, they are developing a technique for inserting Neurocrines, which involves thin needles inserted into a skull using a particular device (NoorLink is working on a robot-like robot to deliver a coin-like brain implant).

The safety and durability of microchips should test in free-moving rodents that Brown’s researchers plan to address in the future. They will then repeat their experiments on the monkeys.

Normico estimates that the range used for rats could reach 770 Neurocrines to cover the surface of the human brain.

Of course, decipher the meaning of all these signals by gathering neural information from these chips.

Brown researchers want to finally be able to record the activity of hundreds of thousands of neurons. These brain signals must be decoded and converted into commands to be transmitted to external devices and perform the user’s actions. It requires a much more complex analysis of neural information than what today’s simpler systems can do.

Meanwhile, the Normico team wants to see if they can make the Neurocrines smaller so that placing hundreds of them inside the brain can cause minimal damage. According to Normiko, this is a microelectronic issue, and it can do, but it is an uphill task. It achieves the desired system, many experiments and studies must be done.