change their activity , which can corrupt the map , so we have to recalibrate the model at the beginning of every session . This means people have to work with a different model every day , so they don ’ t get better at it .
And if , as sometimes happens , something goes wrong and we give them control that isn ’ t very good , they don ’ t get over it on that day , which can be very frustrating for them . It appears the brain isn ’ t plastic enough to
change the activity of specific neurons quickly enough to overcome such problems the same day .
Some scientists are developing ways to allow people to feel what the prosthesis is doing , giving them some tactile feedback to keep track of how things are going . Maybe this could help .
The system has also been adapted to allow people to move their own arms .
How can a computer give movement directions to a real arm ?
In the case of the patient that we ’ ve published about , it ’ s electrical stimulation of the muscles themselves , which seemed the most practical . The energy cost is very high , however . It would be more energy efficient to stimulate the nerves that control the muscles , as they are excellent amplifiers of energy . Yet stimulating the right nerves in the right way
Bill Kochevar uses his own arm to feed himself a spoonful of mashed potato eight years after he lost use of both arms and legs in a bicycle accident . The setup of electrodes implanted in his brain ’ s motor cortex , a brain-computer interface and a system to stimulate his arm and hand muscles also allowed him to do simple but important things such as scratch an itch on his nose . Brain instructions also help to control the black support device . Researchers say the temporary system could soon be adapted for longterm use . CREDIT : CASE WESTERN RESERVE UNIVERSITY
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