Tag: liquid metal

Frontiers of Neuroscience: Neurohacking and Neuromorphics

neural-network-consciousness-downloading-640x353It is one of the hallmarks of our rapidly accelerating times: looking at the state of technology, how it is increasingly being merged with our biology, and contemplating the ultimate leap of merging mind and machinery. The concept has been popular for many decades now, and with experimental procedures showing promise, neuroscience being used to inspire the next great leap in computing, and the advance of biomedicine and bionics, it seems like just a matter of time before people can “hack” their neurology too.

Take Kevin Tracey, a researcher working for the Feinstein Institute for Medical Research in Manhasset, N.Y., as an example. Back in 1998, he began conducting experiments to show that an interface existed between the immune and nervous system. Building on ten years worth of research, he was able to show how inflammation – which is associated with rheumatoid arthritis and Crohn’s disease – can be fought by administering electrical stimulu, in the right doses, to the vagus nerve cluster.

Brain-ScanIn so doing, he demonstrated that the nervous system was like a computer terminal through which you could deliver commands to stop a problem, like acute inflammation, before it starts, or repair a body after it gets sick.  His work also seemed to indicate that electricity delivered to the vagus nerve in just the right intensity and at precise intervals could reproduce a drug’s therapeutic reaction, but with greater effectiveness, minimal health risks, and at a fraction of the cost of “biologic” pharmaceuticals.

Paul Frenette, a stem-cell researcher at the Albert Einstein College of Medicine in the Bronx, is another example. After discovering the link between the nervous system and prostate tumors, he and his colleagues created SetPoint –  a startup dedicated to finding ways to manipulate neural input to delay the growth of tumors. These and other efforts are part of the growing field of bioelectronics, where researchers are creating implants that can communicate directly with the nervous system in order to try to fight everything from cancer to the common cold.

human-hippocampus-640x353Impressive as this may seem, bioelectronics are just part of the growing discussion about neurohacking. In addition to the leaps and bounds being made in the field of brain-to-computer interfacing (and brain-to-brain interfacing), that would allow people to control machinery and share thoughts across vast distances, there is also a field of neurosurgery that is seeking to use the miracle material of graphene to solve some of the most challenging issues in their field.

Given graphene’s rather amazing properties, this should not come as much of a surprise. In addition to being incredibly thin, lightweight, and light-sensitive (it’s able to absorb light in both the UV and IR range) graphene also a very high surface area (2630 square meters per gram) which leads to remarkable conductivity. It also has the ability to bind or bioconjugate with various modifier molecules, and hence transform its behavior. 

brainscan_MRIAlready, it is being considered as a possible alternative to copper wires to break the energy efficiency barrier in computing, and even useful in quantum computing. But in the field of neurosurgery, where researchers are looking to develop materials that can bridge and even stimulate nerves. And in a story featured in latest issue of Neurosurgery, the authors suggest thatgraphene may be ideal as an electroactive scaffold when configured as a three-dimensional porous structure.

That might be a preferable solution when compared with other currently vogue ideas like using liquid metal alloys as bridges. Thanks to Samsung’s recent research into using graphene in their portable devices, it has also been shown to make an ideal E-field stimulator. And recent experiments on mice in Korea showed that a flexible, transparent, graphene skin could be used as a electrical field stimulator to treat cerebral hypoperfusion by stimulating blood flow through the brain.

Neuromorphic-chip-640x353And what look at the frontiers of neuroscience would be complete without mentioning neuromorphic engineering? Whereas neurohacking and neurosurgery are looking for ways to merge technology with the human brain to combat disease and improve its health, NE is looking to the human brain to create computational technology with improved functionality. The result thus far has been a wide range of neuromorphic chips and components, such as memristors and neuristors.

However, as a whole, the field has yet to define for itself a clear path forward. That may be about to change thanks to Jennifer Hasler and a team of researchers at Georgia Tech, who recently published a roadmap to the future of neuromorphic engineering with the end goal of creating the human-brain equivalent of processing. This consisted of Hasler sorting through the many different approaches for the ultimate embodiment of neurons in silico and come up with the technology that she thinks is the way forward.

neuromorphic-chip-fpaaHer answer is not digital simulation, but rather the lesser known technology of FPAAs (Field-Programmable Analog Arrays). FPAAs are similar to digital FPGAs (Field-Programmable Gate Arrays), but also include reconfigurable analog elements. They have been around on the sidelines for a few years, but they have been used primarily as so-called “analog glue logic” in system integration. In short, they would handle a variety of analog functions that don’t fit on a traditional integrated circuit.

Hasler outlines an approach where desktop neuromorphic systems will use System on a Chip (SoC) approaches to emulate billions of low-power neuron-like elements that compute using learning synapses. Each synapse has an adjustable strength associated with it and is modeled using just a single transistor. Her own design for an FPAA board houses hundreds of thousands of programmable parameters which enable systems-level computing on a scale that dwarfs other FPAA designs.

neuromorphic_revolutionAt the moment, she predicts that human brain-equivalent systems will require a reduction in power usage to the point where they are consuming just one-eights of what digital supercomputers that are currently used to simulate neuromorphic systems require. Her own design can account for a four-fold reduction in power usage, but the rest is going to have to come from somewhere else – possibly through the use of better materials (i.e. graphene or one of its derivatives).

Hasler also forecasts that using soon to be available 10nm processes, a desktop system with human-like processing power that consumes just 50 watts of electricity may eventually be a reality. These will likely take the form of chips with millions of neuron-like skeletons connected by billion of synapses firing to push each other over the edge, and who’s to say what they will be capable of accomplishing or what other breakthroughs they will make possible?

posthuman-evolutionIn the end, neuromorphic chips and technology are merely one half of the equation. In the grand scheme of things, the aim of all of this research is not only produce technology that can ensure better biology, but technology inspired by biology to create better machinery. The end result of this, according to some, is a world in which biology and technology increasingly resemble each other, to the point that they is barely a distinction to be made and they can be merged.

Charles Darwin would roll over in his grave!

Sources: nytimes.com, extremetech.com, (2), journal.frontiersin.org, pubs.acs.org

The Future is Here: “Terminator-style” Liquid Metal Treatment

t1000_1For ideal physical rehab, it might be necessary to go a little “cyborg”. That’s the reasoning a Chinese biomedical firm used to develop a new method of repairing damaged nerve endings. Borrowing a page from Terminator 2, their new treatment calls for the use of liquid metal to transmit nerve signals across the gap created in severed nerves. The work, they say, raises the prospect of new treatment methods for nerve damage and injuries.

Granted, it’s not quite on par with the liquid-metal-skinned cyborgs from the future, but it is a futuristic way of improving on current methods of nerve rehab that could prevent long-term disabilities. When peripheral nerves are severed, the loss of function leads to atrophy of the effected muscles, a dramatic change in quality of life and, in many cases, a shorter life expectancy. Despite decades of research, nobody has come up with an effective way to reconnect them yet.

nerveVarious techniques exist to sew the ends back together or to graft nerves into the gap that is created between severed ends. And the success of these techniques depends on the ability of the nerve ends to grow back and knit together. But given that nerves grow at the rate of one mm per day, it can take a significant amount of time (sometimes years) to reconnect. And during this time, the muscles can degrade beyond repair and lead to long-term disability.

As a result, neurosurgeons have long hoped for a way to keep muscles active while the nerves regrow. One possibility is to electrically connect the severed ends so that the signals from the brain can still get through; but up until now, an effective means of making this happen has remained elusive. For some time, biomedical engineers have been eyeing the liquid metal alloy gallium-indium-selenium for some time as a possible solution – a material that is liquid at body temperature and thought to be entirely benign.

Liquid metal nervesBut now, a biomedical research team led by Jing Liu of Tsinghua University in Beijing claims they’ve reconnected severed nerves using liquid metal for the first time. They claim that the metal’s electrical properties could help preserve the function of nerves while they regenerate. Using sciatic nerves connected to a calf muscle, which were taken from bullfrogs, they’ve managed to carry out a series of experiments that prove that the technique is viable.

Using these bullfrog nerves, they applied a pulse to one end and measured the signal that reached the calf muscle, which contracted with each pulse. They then cut the sciatic nerve and placed each of the severed ends in a capillary filled either with liquid metal or with Ringer’s solution – a solution of several salts designed to mimic the properties of body fluids. They then re-applied the pulses and measured how they propagated across the gap.

liquid metal nerves_1The results are interesting, and Jing’s team claim that the pulses that passed through the Ringer’s solution tended to degrade severely. By contrast, the pulses passed easily through the liquid metal. As they put it in their research report:

The measured electroneurographic signal from the transected bullfrog’s sciatic nerve reconnected by the liquid metal after the electrical stimulation was close to that from the intact sciatic nerve.

What’s more, since liquid metal clearly shows up in x-rays, it can be easily removed from the body when it is no longer needed using a microsyringe. All of this has allowed Jing and colleagues to speculate about the possibility of future treatments. Their goal is to make special conduits for reconnecting severed nerves that contain liquid metal to preserve electrical conduction and therefore muscle function, but also containing growth factor to promote nerve regeneration.

future_medicineNaturally, there are still many challenges and unresolved questions which must be resolved before this can become a viable treatment option. For example, how much of the muscle function can be preserved? Can the liquid metal somehow interfere with or prevent regeneration? And how safe is liquid metal inside the body – especially if it leaks? These are questions that Jing and others will hope to answer in the near future, starting with animal models and possibly later with humans..

Sources: technologyreview.com, arxiv.org, cnet.com, spectrum.ieee.org