Researchers at Caltech, the University of South Carolina and Rancho Los Amigos National Rehabilitation Center have developed a better a neural prosthetic system that offers smoother movement of a prosthetic limb than previous devices that controlled by the thoughts of the user. What makes this system unique is that was implanted in a region of the brain where intentions are made, called the posterior parietal cortex (PPC).
Neural prosthetic devices are usually implanted in the brain’s movement center, the motor cortex, and can allow patients with paralysis to control the movement of a robotic limb. However, current neuroprosthetics produce motion that is delayed and jerky–not the smooth and seemingly automatic gestures associated with natural movement. Now, by implanting neuroprosthetics in a part of the brain that controls not the movement directly but rather our intent to move, Caltech researchers have developed a way to produce more natural and fluid motions. With man given the new system is already able to smoothly shake hands, drink a beverage, and even play rock, paper, scissors.
“The PPC is earlier in the pathway, so signals there are more related to movement planning–what you actually intend to do–rather than the details of the movement execution,”principal investigator Richard Andersen of Caltech said in a statement. “When you move your arm, you really don’t think about which muscles to activate and the details of the movement–such as lift the arm, extend the arm, grasp the cup, close the hand around the cup, and so on. Instead, you think about the goal of the movement, for example, ‘I want to pick up that cup of water.’ So in this trial, we were successfully able to decode these actual intents, by asking the subject to simply imagine the movement as a whole, rather than breaking it down into a myriad of components. We expected that the signals from the PPC would be easier for patients to use, ultimately making the movement process more fluid.”
So far, the system has only been implanted in one patient. But the researchers hope this early work will one day result in prosthesis that can be used effortlessly by a wide range of patients.