29 May 2008
Monkey Mind Over Matter
by Kate Melville
A monkey has successfully fed itself using a robotic arm controlled by signals from its brain. The researchers behind the device, from the University of Pittsburgh, say the breakthrough could lead to the development of brain-machine interfaces for people with spinal cord injuries and those with "locked-in" conditions such as Lou Gehrig's disease.
"Our immediate goal is to make a prosthetic device for people with total paralysis," said researcher Andrew Schwartz, a neurobiologist at the University of Pittsburgh School of Medicine. "Ultimately, our goal is to better understand brain complexity."
Previously, brain-machine interfaces have focused on controlling cursor movements displayed on a computer screen. Extending this technology, monkeys in the Schwartz lab are able to move a robotic arm to feed themselves marshmallows and chunks of fruit while their own arms are restrained. Computer software interprets signals picked up by probes the width of a human hair inserted into neuronal pathways in the monkey's motor cortex. The neurons' collective activity is then evaluated using software programmed with a mathematic algorithm and then sent to the arm, which carries out the actions the monkey intended to perform with its own limb.
Because of the massive number of neurons that fire at the same time to control even the simplest of actions, it would be impossible to create probes that capture the firing pattern of each neuron. Hence, the researchers developed a special algorithm that uses limited information from about 100 neurons to fill in the missing signals. Schwartz says the movements are fluid and natural, and that the monkeys come to regard the robotic device as part of their own bodies.
"Now we are beginning to understand how the brain works using brain-machine interface technology," said Dr. Schwartz. "The more we understand about the brain, the better we'll be able to treat a wide range of brain disorders, everything from Parkinson's disease and paralysis to, eventually, Alzheimer's disease and perhaps even mental illness."
Source: University of Pittsburgh Schools of the Health Sciences