http://www.betterhumans.com/News/news.a ... 04-10-28-3
Five Star Stories is getting kind spooky now that the real world is catching up to it...Lasers Bring Brain Interfaces "Out of the Dark Ages"
Light beams said to stimulate and record nerves with greater precision and accuracy
By Liz Brown
10/28/2004 4:31 PM
Credit: Brian Stanback
Light reading: Lasers can precisely stimulate and record nerve activity, suggesting that fiber optic cables could one day link minds with machines
Lasers may allow brain-machine interfaces that far exceed the capabilities of existing devices, permitting people to control artificial limbs through brain-linked fiber optic cables.
So suggest researchers at Vanderbilt University in Nashville, Tennessee who have used a low-intensity infrared laser light to successfully bring nerves to life in rats without touching actual nerve cells.
"This technique brings nerve stimulation out of the Dark Ages," says Anita Mahadevan-Jansen, an assistant professor of biomedical engineering at Vanderbilt.
Currently, neural interfaces mainly stimulate nerves through electrodes wired to the brain. However, the researchers say, the electric method is not ideal as large areas around target neurons are also affected because of the way electricity travels through the tissue.
"Much work is going on around the world trying to make electric nerve stimulation better, but the technique is inherently limited," says Mahadevan-Jansen. "Using lasers instead, we can simultaneously excite and record the responses of nerve fibers with much greater precision, accuracy and effectiveness."
In the experiment, Mahadevan-Jansen and colleagues traced the movement of a nerve's natural electrical impulses through the brain using a special light. From there, they graduated to using a laser to stimulate the nerve and artificially create this activity.
They used the laser to stimulate the sciatic nerve of rats, controlling muscles in the animals' hind legs and individual toes. The method appeared much more accurate than electric stimulation.
Unlike electricity, the laser light could pick off single cells and didn't affect surrounding neurons.
Months from use?
Now that the laser process has proven to be effective, the researchers plan to study the mechanisms behind the stimulation.
The researchers also think it's only a matter of months before a machine could be created that helps neurosurgeons target nerves during rhizotomy, a procedure that frees frozen muscles.
At present, doctors must find affected neural regions by trial and error, striking nerves with an electric probe while patients are awake. Using laser light, the therapy could be less intrusive and more accurate.
Down the road, the researchers believe, a possible application could include an array of fiber optic threads that run from the brain to a prosthetic limb in an optical neural interface.