Medicine
Tue Mar 24, 2020 1:35
Silicon Computing Power for Brain Research
TEHRAN (FNA)- Researchers at Stanford University have developed a new device for connecting the brain directly to silicon-based technologies. While brain-machine interface devices already exist -- and are used for prosthetics, disease treatment and brain research -- this latest device can record more data while being less intrusive than existing options.

"Nobody has taken these 2D silicon electronics and matched them to the three-dimensional architecture of the brain before," said Abdulmalik Obaid, a graduate student in materials science and engineering at Stanford. "We had to throw out what we already know about conventional chip fabrication and design new processes to bring silicon electronics into the third dimension. And we had to do it in a way that could scale up easily."

The device, the subject of a paper published March 20 in Science Advances, contains a bundle of microwires, with each wire less than half the width of the thinnest human hair. These thin wires can be gently inserted into the brain and connected on the outside directly to a silicon chip that records the electrical brain signals passing by each wire -- like making a movie of neural electrical activity. Current versions of the device include hundreds of microwires but future versions could contain thousands.

"Electrical activity is one of the highest-resolution ways of looking at brain activity," said Nick Melosh, professor of materials science and engineering at Stanford and co-senior author of the paper. "With this microwire array, we can see what's happening on the single-neuron level."

The researchers tested their brain-machine interface on isolated retinal cells from rats and in the brains of living mice. In both cases, they successfully obtained meaningful signals across the array's hundreds of channels. Ongoing research will further determine how long the device can remain in the brain and what these signals can reveal. The team is especially interested in what the signals can tell them about learning. The researchers are also working on applications in prosthetics, particularly speech assistance.

Worth the wait

The researchers knew that, in order to achieve their aims, they had to create a brain-machine interface that was not only long-lasting, but also capable of establishing a close connection with the brain while causing minimal damage. They focused on connecting to silicon-based devices in order to take advantage of advances in those technologies.

"Silicon chips are so powerful and have an incredible ability to scale up," said Melosh. "Our array couples with that technology very simply. You can actually just take the chip, press it onto the exposed end of the bundle and get the signals."

One main challenge the researchers tackled was figuring out how to structure the array. It had to be strong and durable, even though its main components are hundreds of minuscule wires. The solution was to wrap each wire in a biologically-safe polymer and then bundle them together inside a metal collar. This assures the wires are spaced apart and properly oriented. Below the collar, the polymer is removed so that the wires can be individually directed into the brain.

Existing brain-machine interface devices are limited to about 100 wires offering 100 channels of signal, and each must be painstakingly placed in the array by hand. The researchers spent years refining their design and fabrication techniques to enable the creation of an array with thousands of channels -- their efforts supported, in part, by a Wu Tsai Neurosciences Institute Big Ideas grant.

"The design of this device is completely different from any existing high-density recording devices, and the shape, size and density of the array can be simply varied during fabrication. This means that we can simultaneously record different brain regions at different depths with virtually any 3D arrangement," said Jun Ding, assistant professor of neurosurgery and neurology, and co-author of the paper. "If applied broadly, this technology will greatly excel our understanding of brain function in health and disease states."

After spending years pursuing this ambitious-yet-elegant idea, it was not until the very end of the process that they had a device that could be tested in living tissue.

"We had to take kilometers of microwires and produce large-scale arrays, then directly connect them to silicon chips," said Obaid, who is lead author of the paper. "After years of working on that design, we tested it on the retina for the first time and it worked right away. It was extremely reassuring."

Following their initial tests on the retina and in mice, the researchers are now conducting longer-term animal studies to check the durability of the array and the performance of large-scale versions. They are also exploring what kind of data their device can report. Results so far indicate they may be able to watch learning and failure as they are happening in the brain. The researchers are optimistic about being able to someday use the array to improve medical technologies for humans, such as mechanical prosthetics and devices that help restore speech and vision.

Additional Stanford co-authors include Mina-Elraheb Hanna (co-lead), former doctoral student in the Melosh lab; Yu-Wei Wu (co-lead), a former postdoctoral fellow in the Ding lab who is now at the Institute of Molecular Biology, Academia Sinica; Nora Brackbill, a graduate student in the Chichilnisky lab; and E.J. Chichilnisky, the John R. Adler Professor of Neurosurgery, and professor of ophthalmology. Other co-authors are from the Francis Crick Institute (co-lead), University College London (co-lead), Paradromics Inc. (co-lead), and ETH Zurich.

Chichilnisky is a member of Stanford Bio-X and the Wu Tsai Neurosciences Institute. Ding is a member of Stanford Bio-X, the Maternal & Child Health Research Institute (MCHRI), and the Wu Tsai Neurosciences Institute. Melosh is a member of Stanford Bio-X and the Wu Tsai Neurosciences Institute; an affiliate of the Precourt Institute for Energy; and a faculty fellow of Stanford ChEM-H.

This research was supported by the National Institutes of Health, DARPA, the Wu Tsai Neurosciences Institute, the Francis Crick Institute, the Wellcome Trust, the Human Frontier Science Program, and the Medical Research Council.

 

 

 

Bottom top
Iraqi Analyst: US Looking for Reoccupation of Iraq

TEHRAN (FNA)- A senior Iraqi political analyst warned against a new plot by Washington to deploy the elite forces after evacuating its so-called diplomatic centers and shutting down important military bases such as al-Qayyareh, K1 and Kirkuk.
Top Commander Informs of Screening 58 Million Iranians for Coronavirus

TEHRAN (FNA)- Chief of Staff for Iran's Armed Forces Major General Mohammad Bagheri announced that over 58 million people have so far been screened for coronavirus infection by Medical Basij (Volunteer) Organization across the country.
Crisis Center Says Coronavirus Cases in Russia Surpass 1,500

TEHRAN (FNA)- The number of the coronavirus cases in Russia has risen by 270 over the past day to 1,534, with 65 regions affected by the disease, the anti-coronavirus crisis center reported on Sunday.
Report: Turkey Deploys US-Made Air Defense System to Syria’s Idlib

TEHRAN (FNA)- Turkey has reportedly deployed a US-made air defense system to Idlib as Ankara beefs up its military presence in the militant-held Syrian region despite a ceasefire reached earlier this month to halt an escalation.
Public Health Chief Warns Germany's Health System Could Buckle If Faced with Crisis Seen in Italy

TEHRAN (FNA)- Germany’s health infrastructure would not be able to cope with the huge influx of Covid-19 patients currently seen in Italy, the head of Robert Koch Institute (RKI) announced.
Defense Minister Informs of Producing 2mln ltr of Disinfectants, 1.5mln Masks

TEHRAN (FNA)- Iran's Defense Minister Brigadier General Amir Hatami announced on Sunday that over 2.5mln liters of disinfectants and 1.5mln filtered have been produced and supplied to the health bodies by the Defense Industries Organization.
Iran Reports 2,901 New Cases of Coronavirus, over 12,391 Recoveries

TEHRAN (FNA)- The Iranian health ministry announced on Sunday that 2,901 new cases of infection to COVID-19 virus have been identified in the country, adding that 2,640 patients have died so far.
Official Says Americans Shed Crocodile Tears

TEHRAN (FNA)- Deputy Health Minister Iraj Harirchi said that the Americans just shed crocodile tears, rejecting the US claim to send assistance to Iran amid combating coronavirus epidemic.
Iran Able to Do over 10,000 Corona Tests Daily

TEHRAN (FNA)- Deputy Health Minister for Treatment Qassem Jan Babayi informed of Iran's capacity to do more than 10,000 corona tests, adding that there are 90 laboratories in the country for the purpose.
Pentagon's New Plot against Iraq's Resistance Groups Unveiled

TEHRAN (FNA)- Several political analysts have unveiled a new decision by the US for escalation of tensions against the resistance groups in Iraq could lead to the rise to power of the US-backed candidate for prime minister's post, Adnan al-Zorfi, or an eventual military coup in that country.
Iran, Brazil Vow to Broaden Mutual Cooperation

TEHRAN (FNA)- Iran's newly-appointed Ambassador to Brasilia Hossein Gharibi voiced his country's readiness to expand bilateral relations with Brazil in different fields.
UK PM Says Coronavirus Outbreak to Worsen

TEHRAN (FNA)- Prime Minister Boris Johnson warned Britons in a letter to 30 million households that things will get worse before they get better, as he himself self-isolates in Downing Street to recover from the coronavirus.
Spain Endures Another Record Day for Coronavirus Deaths, Nationwide Tally Rises to 6,500

TEHRAN (FNA)- Spain's coronavirus death toll rose by more than 800 cases overnight to over 6,500, the health ministry announced, marking the highest daily rise in fatalities. However, the rate of new cases dropped significantly amid signs that measures introduced to combat the virus are having an effect.
Italy Blasts European Commission Chief, Says Europe Needs 'Great Marshall Plan' to Battle Pandemic Crisis

TEHRAN (FNA)- Italian Economy Minister Roberto Gualtieri clashed with European Commission Chief Ursula von der Leyen after she stated that the EU is not planning to issue 'corona bonds' to help countries decimated by Covid-19.
Abe Warns Citizens of 'Unprecedented' Economic Measures, Long Battle Against COVID-19

TEHRAN (FNA)- Japanese Prime Minister Shinzo Abe on Saturday called upon citizens to prepare themselves for the "worst-case scenario" and lengthy battle against COVID-19 that will include unprecedented economic measures.