Intel Inside

I've been fascinated by recent research out of Brown, Caltech and Duke in neurological control of prosthesis and software. Earlier posts (10/03 and 7/04) detailed the experiments with monkeys, when chips in their brains enabled them to move robotic arms with just the power of thought.

Today, via Drudge, a Guardian report on the human trials:

There's a hand lying on the blanket on Matt Nagle's desk and he's staring at it intently, thinking "Close, close," as the scientists gathered around him look on. To their delight, the hand twitches and its outstretched fingers close around the open palm, clenching to a fist.

In that moment, Nagle made history. Paralysed from the neck down after a vicious knife attack four years ago, he is the first person to have controlled an artificial limb using a device chronically implanted into his brain...

...There are huge hurdles ahead. No one knows how much information we can usefully decipher from the electrical fizz of the brain's 100bn neurons. More importantly, scientists are still in the dark as to what effect, if any, long term implants will have on the human brain, or how its circuitry will cope with the new tasks demanded of it.

Nagle got involved in the latest trial after hearing about John Donoghue, a professor of neuroscience at Brown University on Rhode Island, whose company Cyberkinetics has developed an implant called BrainGate.

The reporting seems pretty good (I can forgive the UK writer for saying Brown University is "on" Rhode Island). Unlike earlier breathless news articles, this one seems grounded in a healthy skepticism, and notes the significant limitations and hurdles ahead.

Implants suffer from a number of drawbacks, the first being that they demand invasive surgery, with attendant risks. Second, implanted electrodes cause at least some inflammation of the brain tissues they push into. As well as obvious medical concerns, if the inflammation is significant, it can smother any signals the electrodes might pick up.

"Every one you put in gives some inflammation, but it's minor. We're still working on making electrodes more biocompatible, but we've got monkeys who have so far survived for nearly five years with implants and they are fine," says Nicolelis. "The thing is, to do what we want to do, to get that level of control, you have to get into the brain."

It's always been a matter of concern -- the human inflammatory response is a good deal more vigorous than that of even closely related primates. However, noninvasive techniques for mapping brain activity to mechanical devises are under development. The only question is, will brain chip implants, with their greater risks and greater control, win out over the safer and less precise (but potentially trainable) electrode caps? Regardless, this technology seems to be moving faster, and overcoming more obstacles, than tissue-engineered approaches to repairing severed spinal cord.