Text 306, 124 rader
Skriven 2005-04-20 20:05:58 av Marnie Trosclair (1:167/133.0)
     Kommentar till en text av Steve Asher
Ärende: Chips on the Brain
==========================
Hey Steve,

This article is from one of the links I listed the other day.
It's the subject of the story that just appeared on ABC News.


 Matt Nagle has a chip that was placed on his brain that translates
 his thoughts to a computer.  He is connected to the computer via a
 cable that is screwed into his head.

http://www.guardian.co.uk/life/feature/story/0,13026,1448140,00.html  


 Meet the mind readers

 Paralysed people can now control artificial limbs by thought alone.
 Ian Sample reports
 Thursday March 31, 2005
 The Guardian

 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.

 The experiment took place a few months ago as part of a broader trial
 into what are known in the business as brain-computer interfaces.
 Although it is early days, aficionados of the technology see a world
 where brain implants return ability to those with disability,
 allowing them to control all manner of devices by thought alone.
 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.  Under Donoghue's instruction, Nagle was given a general
 anaesthetic before a disc the size of a poker chip was cut from his
 skull.  After making an incision in the brain's protective membrane,
 a tiny array of 96 hair-thin electrodes, each protruding about a
 millimetre, was pressed onto the surface of his brain, just above a
 region of the sensory motor cortex that is home to the neuronal
 circuitry governing arm and hand movement.  With the electrodes in
 position, the bony disc was replaced, leaving room for a tiny wire to
 connect the electrodes to a metal plate the size of a 10p piece that
 sits on Nagle's head like a button.

 To read brain signals from Nagle's motor cortex, Donoghue's
 researchers attach an amplifier to the metallic button on his head
 and run a cable to a computer.  When he's hooked up, the tiny
 voltages of the sparking neurons beneath the electrodes produce a
 series of brainwaves that dance on the computer screen.

 Since having the electrodes implanted in June last year, Nagle has
 been test-driving the technology, seeing what he, and it, are capable
 of.  "We're evaluating his ability to do a whole range of things.
 We've hooked him to a computer that lets him turn a TV on and off,
 change channel and turn the volume up and down," says Donoghue.

 The success of the technology relies on being able to decipher
 accurately the electrical activity within Nagle's brain and turn it
 into useful actions.  The trials started tentatively.  Nagle had been
 unable to move any of his limbs for nearly four years.  The
 scientists had no idea how this would have affected the brain signals
 that normally control movement.  Would they have fizzled out through
 lack of use, much as muscles waste away in the wheelchair-bound?  
 "No one knew if it would work in someone with these injuries, but 
 simply by asking him to imagine moving we got useful signals and it 
 was amazing.  I was overwhelmed by how beautifully the cells were 
 still working," says Donoghue.

 Getting the signals is one thing; deciphering them is another.  But
 Donoghue's team found that some simple rules held - if the brain
 wanted to move the hand to the right, certain cells would fire a
 rapid series of impulses.  If the brain was willing the hand to move
 left, the cells fired a different number of times.  Other information,
 such as where the hand should end up, what trajectory it should take,
 and how quickly it should move, is also embedded in the electrical
 signals.

 Part of the difficulty in reading brain signals is that while even a
 simple movement such as raising a hand requires electrical signals
 from many regions of the brain, the implanted electrodes pick up just
 a tiny fraction of those that fire.  "We're recording only a dozen or
 so, when a million might be active," says Donoghue, who likens the
 process to dropping a microphone into a crowded room and trying to
 get the gist of all the conversations going on.

 The limitations of taking signals from just a few active neurons have
 become apparent in the trial.  Many of the tasks Nagle is set involve
 moving a cursor around a screen by thinking which way it should move.
 But the cursor jiggles, making it difficult to select icons on the
 screen with any precision.  "We could smooth it out using software,
 but at the moment, we want to see if Matthew can learn to control the
 wobble," says Donoghue, who is recruiting four other patients to
 complete the trial.  "If he can do that, he can use computer software
 to answer emails, and if he can do that, he could be employed."

 Ultimately, Donoghue says there should be no need to connect cables
 to peoples' heads to read their minds.  Miniaturisation should bring
 smaller devices that can be powered through unbroken skin and
 transmit signals wirelessly from the brain to a processor worn on a
 belt that triggers the intended device.


The article continues.... at this address:

http://www.guardian.co.uk/life/feature/story/0,13026,1448140,00.html  

 
 


--- Maximus/2 3.01
 * Origin: Juxtaposition BBS, Telnet:juxtaposition.dynip.com (1:167/133)