Idoya turns robotics into monkey business
IF IDOYA could talk, she would have plenty to boast about. The 5.5-kilogram, 80-centimetre monkey has made a 90-kilogram, 150-centimetre humanoid robot walk on a treadmill using only her brain activity.
Her feat was even more remarkable because she was in North Carolina and the robot was in Japan.
It was the first time that brain signals had been used to make a robot walk, said Dr Miguel Nicolelis, a neuroscientist at Duke University, whose laboratory designed and carried out the experiment.
In 2003, Dr Nicolelis' team proved that monkeys could use their thoughts to control a robotic arm for reaching and grasping.
These experiments, Dr Nicolelis said, were the first steps towards a brain machine interface that might help paralysed people walk by directing devices with their thoughts.
Electrodes in the person's brain would send signals to a device worn on the hip, like a mobile phone or pager, which would relay those signals to a pair of braces, a kind of external skeleton, worn on the legs. "When that person thinks about walking, walking happens," Dr Nicolelis said.
Until ways are found to safely implant electrodes into human brains, most research will remain focused on animals.
In preparing for the experiment, Idoya was trained to walk upright on a treadmill, holding onto a bar. She got treats as she walked at different speeds, forwards and backwards.
Meanwhile, electrodes implanted in the so-called leg area of Idoya's brain recorded the activity of 250 to 300 neurons that fired while she walked. Some neurons became active when her ankle, knee and hip joints moved. Others responded when her feet touched the ground. And some fired in anticipation of her movements.
To obtain a detailed model of Idoya's leg movements, the researchers painted her ankle, knee and hip joints with fluorescent make-up and, using a high-speed camera, captured her movements on video.
The video and brain cell activity were then combined and translated into a format that a computer could read.
This format is able to predict with 90% accuracy all permutations of Idoya's leg movements three to four seconds before the movement takes place.
On Thursday, Idoya stepped onto her treadmill and began walking at a steady pace with electrodes implanted in her brain. Her walking pattern and brain signals were collected, fed into the computer and transmitted over a high-speed internet link to a robot in Kyoto.
The robot, called CB, for "computational brain", has the same range of motion as a human. It can dance, squat, point and "feel" the ground.
As Idoya's brain signals streamed into CB's actuators, her job was to make the robot walk steadily via her own brain activity. She could see the back of CB's legs on an enormous movie screen in front of her treadmill and received treats if she could make the robot's joints move in synchrony with her own leg movements.
As Idoya walked, CB walked at exactly the same pace. Recordings from Idoya's brain revealed that her neurons fired each time she took a step and each time the robot took a step.
"It's walking!" Dr Nicolelis said. "That's one small step for a robot and one giant leap for a primate."
NEW YORK TIMES