Feb 05 2009

Neurons and Computer Chips

Edinburgh University researchers have developed a technique whereby they can grow neurons in a specific pattern determined by a silicon chip. This is yet another small advance in this area of research – the interface between biology and computers.

The researchers were able to etch a pattern in silicon and then bath that chip in a bath of specific proteins. The proteins – likely including some growth factors and other hormones – coaxed the neurons to grow along the pre-determined pathways.

This represents an incremental technological step, but an important one. There are several research programs working on aspects of this technology – getting cells, whether neurons or stem cells, to grow how they want them to. Others are working on the interface of neurons and computer chips – getting them to talk to each other.

This technology is at an obviously early stage. It is similar to the time when physicists and engineers were making basic discoveries about electricity and how to control it. Each new discovery, about capacitors, circuits, resistance, etc., added one more piece to the puzzle. At the time I don’t think anyone could have seen how controlling electrical circuits would soon transform civilization.

I see the same thing happening with the technology to interface computers and biology – we are making baby-step advances in this technology, which are by themselves not that impressive, but I think we can see where this is headed.

If we extrapolate into the future, when all the pieces are in place, we will have incredible control over biological tissue and be able to combine that with increasingly sophisticated, small, and powerful computers. Researchers like speculating about possible applications. One obvious application is the repair of damaged nerves and spinal cords.  We could theoretically use such an implant to coax neurons to grow and make connections across an area of damage. Or we could reconnect nerves to muscle tissue, or even repair the damaged muscle itself.

When applied to stem cells this technology could lead to the ability to grow custom-designed tissue and organs. We are simultaneously making advances in stem-cell technology – for example researchers have discovered that by altering only four genes they can change an adult-derived cell into a stem cell with all the properties (at least so far investigated) of an embryonic stem cell.

So again if we flash forward, this technology may allow us to take a skin cell from you and then grow you a new liver to replace your failing one.

The other category of applications is in brain-computer interfacing. Getting neurons to grow on a chip means that those neurons can connect to and communicate with your brain cells and also connect to and communicate with a computer chip. Our brains are wonderfully plastic, so it is plausible that they can adapt these new connections to actual function.

For example, someone with Parkinson’s disease has damage in a part of the brain called the basal ganglia. This is a circuit deep in the brain that is actually pretty-well understood. It regulates voluntary muscle activity, tweaking the gain of motor activation so that muscle control is smooth. Too little inhibition from this circuit and patients will have uncontrollable movements. Too much, and they will be stiff, even frozen. Drugs can help for a while, but they don’t replace the lost circuit – they cannot provide the moment-to-moment feedback loop necessary for optimal function.

One way to actually fix Parkinson’s disease is with stem cells. Current transplants with fetal tissue are really just drug delivery systems – they create dopamine and dump it into the local environment, but they don’t repair the circuit. Stem cells that actually repair the lost connections could potentially be a cure, however. It is unclear how far off this technology is.

Another option suggested by this current research is to build a replacement circuit for the basal ganglia in silicon (or whatever) interfaced with neurons and implant that, so that the neurons can make the connection between the basal ganglia and the replacement circuit. This would be a genuine brain prosthetic.

Brain prosthetics could also be used to treat epilepsy – detecting seizures and stopping them in their tracks, before they spread.  Basic forms of this are already in the works. I think we will see this soon.

And of course, as I have discussed in previous posts, brain function enhancement could be another application. Wireless chips in our brain could give us genuine ESP, or give us remote control over any computer-controlled device. It could also be a great communication aid for those with various impairments. Imagine the day when someone who is locked-in (paralyzed below the eyes) can still communicate with the world just by thinking, or can operate their motorized wheelchair complete with robotic arms.

Today this may sound like science fiction, but it is all a highly plausible extrapolation from existing research and technology.  The fine details and the precise time-frame are hard to predict, but the broad brushstrokes of where this future technology will take us seems pretty clear. Actually if I am missing anything it is that there will be transformative applications of this type of technology that I have not yet conceived of.

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