is pretty complicated — you can ’ t simply shock them into action .
Having a person move their own arm is an important achievement , although it is slow and definitely not as dexterous as we ’ d like it to
be . To a large extent , I think this is because of our lack of understanding of the signals going from our brain into the limbs .
The number of limbs we can use is tightly constrained by our evolutionary history . Can you imagine that our brain could ever be adapted to using an extra limb ?
In a way , we already do that today , by using extensions
This diagram describes the basic steps for controlling prosthetic devices via brain activity . A microelectrode array ( 1 ) implanted in the brain records the activity of several neurons ( 2 ). These patterns are sent to a computer that uses a decoding algorithm ( 3 ) to translate them into instructions for an output device , such as a robotic arm ( 4 ). Sensory feedback ( 5 ), which is usually just visual but can be tactile as well , allows the user to adjust brain activity .
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