Ramblings of an Edge Runner
Saturday, May 21, 2011
Thursday, May 19, 2011
Monday, May 16, 2011
Monday, May 9, 2011
Sunday, April 24, 2011
Bionic Leg Undergoing Clinical Trials
"A 'bionic' leg designed for people who have lost a lower leg is undergoing clinical trials sponsored by the US Army. The researchers hope the leg will be able to learn the patient's nerve signal patterns and be able to move in response to the patient's own muscles and nerves (abstract). Electrodes are attached to nine muscles in the thigh to detect the patterns in which the nerve signals are fired. Different patterns correspond to different intended movements. In the current stages of training, the volunteers are wired up to the electrodes and learn how to use the muscles to make a computer avatar move on screen. Results showed that all the volunteers could control the avatar’s knee and ankle movements from neural information from the thigh, with amputees achieving 91 percent accuracy of movement and the non-amputees achieving 89 percent."
Thursday, April 21, 2011
Wednesday, December 15, 2010
Neuroscientists create the first brain-controlled exoskeleton
ENHANCED BRAIN-MACHINE INTERFACE TAPS INTO ADDITIONAL SENSES
Study shows sensory feedback gives monkeys better control of computer cursors
Monkeys moved thought-controlled computer cursors more quickly and accurately when provided with additional sensory feedback, according to a new study in the Dec. 15 issue of The Journal of Neuroscience. While most brain-machine technologies rely only on visual feedback, this study demonstrated that these systems can be improved when users have additional input, such as a sense of the arm’s position and motion, a sensation known as proprioception.
With the aid of brain-controlled devices, paralyzed people have been able to send e-mail, play video games, and operate robotic arms. In this study, researchers led by Nicholas Hatsopoulos, PhD, of the University of Chicago, aimed to help further develop such machines for people who may still experience feeling in paralyzed limbs, including many patients with spinal cord injury and amyotrophic lateral sclerosis (ALS).
“Organisms use multiple senses, including sight and touch, as feedback to adjust motor behavior,” Hatsopoulos said. “The ability to feel movements of the limbs and body is critical for normal motor control. Loss of this sense results in movements that are slow, poorly coordinated, and require great concentration.”
The authors worked with two adult rhesus macaques to assess a system that incorporates a sense of movement. Each monkey was first trained to control a cursor using brain signals only; electrodes collected and processed data from the monkeys’ motor cortex cells and transmitted those commands to the computer. Basic science research has shown that simply thinking about a motion activates brain cells in the same way that making the movement does, so each monkey needed to only think about moving a cursor to do it.
The researchers equipped each animal with a robotic “sleeve” that fit over an arm. In the first part of the experiment, the monkeys controlled the cursor by simply looking at the computer screen. In the second part, the robotic device moved the monkey’s relaxed arm in tandem with the cursor movement, so the monkey could sense the cursor’s motion in time and space. The authors found when the monkeys had the extra sensation, the cursor hit the target faster and more directly. The results also showed increased movement-related information in the activity of motor cortex cells, compared with visual-only feedback.
Hatsopoulos said his group’s findings may pave the way for enhanced brain-controlled devices that include multiple forms of natural or even artificially produced sensory feedback. “Wearable exoskeletal robots could provide sensory information to patients with full or partial feeling,” he said. “Alternatively, direct stimulation of the relevant area of the cortex could be used to replicate sensory feedback in patients who have lost both motor and sensory function.”
The research was supported by the National Institute of Neurological Disorders and Stroke and the Paralyzed Veterans of America Research Foundation.
The Journal of Neuroscience is published by the Society for Neuroscience, an organization of more than 40,000 basic scientists and clinicians who study the brain and nervous system. Hatsopoulos can be reached at nicho@uchicago.edu.