epski
10-14-03, 01:40 AM
http://www.betterhumans.com/News/news.aspx?articleID=2003-10-13-8
Monkeys Become One with Robot Arm
Dwayne Hunter
Betterhumans Staff
Monday, October 13, 2003, 5:06:15 PM CT
Rhesus monkeys have been taught to control and assimilate a robot arm using signals from their brain, a development that promises new prosthetic devices that give users the sense of being a natural extension.
As many as 200,000 people live with partial or nearly total paralysis in the US alone, where there are about 11,000 new spinal cord injuries each year.
Most research aimed at recovering motor function has focused on repairing damaged nerve fibers. In animal experiments, researchers have succeeded in restoring limited movement with this approach.
Regenerating nerves and restoring complex motor behavior in humans, however, has proven to be a far more difficult task, prompting researchers to explore alternatives to spinal cord rehabilitation.
Brain electrodes
Neurobiologist Miguel Nicolelis from Duke University Medical Center in Durham, North Carolina and colleagues have previously demonstrated a brain-signal recording and analysis system that enabled them to decipher brain signals from owl monkeys.
The researchers have now advanced this work by teaching rhesus macaque monkeys to consciously control the movement of a robot arm.
The researchers first implanted an array of micro-electrodes—each smaller than the diameter of a human hair—into areas of the brain in two female rhesus macaque monkeys that are known to be involved in producing multiple output commands to control complex muscle movement (the frontal and parietal lobes).
In one animal, 96 electrodes were implanted. In the other, 320. (italics mine -- here's a mild example of this type of vivisection in cats: http://home.pacbell.net/epski/vivisection.mov)
The faint signals from the electrode arrays were detected and analyzed by a computer system the researchers had developed to recognize patterns of signals that represented particular movements by an animal's arm.
Assimilating control
The researchers recorded and analyzed the output signals from the monkeys' brains and also taught the animals how to use a joystick to both position a cursor over a target on a video screen and to grasp the joystick with a specified force.
Next, the researchers made the cursor more than a simple display, incorporating dynamic movements, such as inertia and momentum, of a robot arm functioning in another room.
The monkeys' performance initially declined when the robot arm was included in the feedback loop, however, the scientists found that the monkeys quickly learned to allow for these dynamics and became proficient in manipulating the robot-reflecting cursor.
After the joystick was removed, the monkeys continued to move their arms to manipulate and "grab" the cursor, thus controlling the robot arm.
"The most amazing result, though, was that after only a few days of playing with the robot in this way, the monkey suddenly realized that she didn't need to move her arm at all," says Nicolelis.
"Her arm muscles went completely quiet, she kept the arm at her side and she controlled the robot arm using only her brain and visual feedback," says Nicolelis. "Our analyses of the brain signals showed that the animal learned to assimilate the robot arm into her brain as if it was her own arm."
Adaptable brain
Nicolelis explains that the neurons from which his team was recording encode different kinds of information.
What was surprising to the scientists was that the animals could learn to time the activity of the neurons to basically control different types of parameters sequentially. For example, after a group of neurons moved the robot to a certain point, these same cells would produce the force output that the animals needed to hold an object.
The Duke team had never encountered this ability in animals before.
"Such findings tell us that the brain is so amazingly adaptable that it can incorporate an external device into its own 'neuronal space' as a natural extension of the body," says Nicolelis.
"Actually, we see this every day, when we use any tool, from a pencil to a car. As we learn to use that tool, we incorporate the properties of that tool into our brain, which makes us proficient in using it," he says.
While Nicolelis says more science and engineering must be done to further develop the technology, he thinks the brain-machine interface system could have direct application to the development of neural interface prosthetics.
The researchers reported the study in the Proceedings of the National Academy of Sciences (read abstract).
Copyright © 2002-2003 Betterhumans
Evidently animal research makes us "better humans.
Monkeys Become One with Robot Arm
Dwayne Hunter
Betterhumans Staff
Monday, October 13, 2003, 5:06:15 PM CT
Rhesus monkeys have been taught to control and assimilate a robot arm using signals from their brain, a development that promises new prosthetic devices that give users the sense of being a natural extension.
As many as 200,000 people live with partial or nearly total paralysis in the US alone, where there are about 11,000 new spinal cord injuries each year.
Most research aimed at recovering motor function has focused on repairing damaged nerve fibers. In animal experiments, researchers have succeeded in restoring limited movement with this approach.
Regenerating nerves and restoring complex motor behavior in humans, however, has proven to be a far more difficult task, prompting researchers to explore alternatives to spinal cord rehabilitation.
Brain electrodes
Neurobiologist Miguel Nicolelis from Duke University Medical Center in Durham, North Carolina and colleagues have previously demonstrated a brain-signal recording and analysis system that enabled them to decipher brain signals from owl monkeys.
The researchers have now advanced this work by teaching rhesus macaque monkeys to consciously control the movement of a robot arm.
The researchers first implanted an array of micro-electrodes—each smaller than the diameter of a human hair—into areas of the brain in two female rhesus macaque monkeys that are known to be involved in producing multiple output commands to control complex muscle movement (the frontal and parietal lobes).
In one animal, 96 electrodes were implanted. In the other, 320. (italics mine -- here's a mild example of this type of vivisection in cats: http://home.pacbell.net/epski/vivisection.mov)
The faint signals from the electrode arrays were detected and analyzed by a computer system the researchers had developed to recognize patterns of signals that represented particular movements by an animal's arm.
Assimilating control
The researchers recorded and analyzed the output signals from the monkeys' brains and also taught the animals how to use a joystick to both position a cursor over a target on a video screen and to grasp the joystick with a specified force.
Next, the researchers made the cursor more than a simple display, incorporating dynamic movements, such as inertia and momentum, of a robot arm functioning in another room.
The monkeys' performance initially declined when the robot arm was included in the feedback loop, however, the scientists found that the monkeys quickly learned to allow for these dynamics and became proficient in manipulating the robot-reflecting cursor.
After the joystick was removed, the monkeys continued to move their arms to manipulate and "grab" the cursor, thus controlling the robot arm.
"The most amazing result, though, was that after only a few days of playing with the robot in this way, the monkey suddenly realized that she didn't need to move her arm at all," says Nicolelis.
"Her arm muscles went completely quiet, she kept the arm at her side and she controlled the robot arm using only her brain and visual feedback," says Nicolelis. "Our analyses of the brain signals showed that the animal learned to assimilate the robot arm into her brain as if it was her own arm."
Adaptable brain
Nicolelis explains that the neurons from which his team was recording encode different kinds of information.
What was surprising to the scientists was that the animals could learn to time the activity of the neurons to basically control different types of parameters sequentially. For example, after a group of neurons moved the robot to a certain point, these same cells would produce the force output that the animals needed to hold an object.
The Duke team had never encountered this ability in animals before.
"Such findings tell us that the brain is so amazingly adaptable that it can incorporate an external device into its own 'neuronal space' as a natural extension of the body," says Nicolelis.
"Actually, we see this every day, when we use any tool, from a pencil to a car. As we learn to use that tool, we incorporate the properties of that tool into our brain, which makes us proficient in using it," he says.
While Nicolelis says more science and engineering must be done to further develop the technology, he thinks the brain-machine interface system could have direct application to the development of neural interface prosthetics.
The researchers reported the study in the Proceedings of the National Academy of Sciences (read abstract).
Copyright © 2002-2003 Betterhumans
Evidently animal research makes us "better humans.