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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 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 of our body such as tools , computers or cars . Some of those are quite complex and very different from our body , yet we learn to handle them reasonably well and largely without thinking . And just like the monkeys in our experiments — which were moving a cursor or a robotic arm with their brain activity , even though they still had functioning arms — people have a tendency to use their own bodies less if they can use a more efficient device instead .
Do you think that all of us might one day consider it practical to put an array into our brain so we can communicate with a computer or other devices more directly ?
I don ’ t . Evolution has given us such fabulous natural interfaces that I think the barrier of brain surgery will remain too high . There ’ s always a risk of something going wrong , so I don ’ t think we should use implants for pure augmentation like that . Some people will do dangerous things , of course , but fortunately , you can ’ t easily stick an electrode in the right place in your own brain .
Have you heard of
neurologist Phil Kennedy ? He was the first person to implant an electrode in a human permanently , and he later had himself implanted in Belize , as no one in the United States would do anything like that . I find that disturbing — he ’ s a perfectly healthy , very bright man .
I think the aim of the field should be to create the opportunity for people with paralysis to restore or achieve typical abilities . For people who want to be superenabled , I think we need some serious regulations , as that could be extraordinarily disruptive . It also raises other issues — if I am rich and you are not , and only my child gets a brain booster implant , this creates a very unfair situation .
How do you apply such ethical considerations to your own work ?
I think we should always strive to make the technologies we create available to as many people as possible . That doesn ’ t mean we should stop developing or producing them because they currently cost too much and we can ’ t give them to everybody who needs them . But eventually , that should be the goal .
What is the biggest obstacle to getting this technology out there to people who need it ?
One issue is that the arrays tend to degrade over time in the rather harsh environment