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Summary:

Researchers were able to replicate sensations of pressure and grabbing an object by delivering electrical signals to different parts of the brain.

Robot Hand
photo: PNAS, 2013

Each year prosthetic limbs become more incredible, whether they allow a wearer to run at Olympic speeds or are controlled by thought alone. But most still lack a sense of touch, which would give the wearer greater control and connection to their prosthetic limb.

University of Chicago researchers have published a paper detailing how stimulating a prosthetic limb wearer’s brain with electrical signals could replicate feelings of touch. They worked with monkeys, which they outfitted with electrodes connected to different areas of the brain associated with touch. The researchers studied their brain’s response to different types of touch to pinpoint the type and amount of electrical signal that would best replicate the sensation.

The monkeys went through several touch exercises with their normal hand and an unstimulated brain. The same exercises were conducted with a prosthetic hand, which was equipped with pressure sensors to register instances of touch. Pressure registered by the hand was converted into electrical signals, which the electrodes delivered to the monkeys’ brains.

The researchers found that the monkeys responded the same in both situations. This includes when the monkeys first touched or released an object, sensing pressure and identifying where on their finger they touched an object — all important facets of touch.

The researchers hold that touch is an essential addition to prosthetic limbs. While some limbs can take in signals from the brain to control movement, they aren’t really complete until they can also send signals back to the brain.

“The algorithms to decipher motor signals have come quite a long way, where you can now control arms with seven degrees of freedom. It’s very sophisticated. But I think there’s a strong argument to be made that they will not be clinically viable until the sensory feedback is incorporated,” assistant professor Sliman Bensmaia said in a release. “When it is, the functionality of these limbs will increase substantially.”

The researchers have yet to test the system in humans. The system would also need to become more sophisticated before a person could incorporate it into their daily life, when it would have to judge and replicate sensations of touch for a much wider range of activities.

  1. video or it didn’t happen.

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    1. You are the reason comments on the internet should be disabled.

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    2. The video would be too horrific to show. Amputating a monkeys arm then wiring into its brain to test a theory

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      1. The study doesn’t say anything about amputation; they use a shoulder nerve block. There’s brain wiring though, which isn’t real pretty. They ought to jump straight to human research on this one; they’d learn more, and keep PETA off.

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    3. Technology like this has been around for some time, a friend of mine used to build and test implants that were placed in the brains of monkeys and people. Stimulation was the next step and not far off in the early 2000’s. Here is the companies website: http://www.cyberkinetics.com/

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  2. Why use monkeys. Use MS-13 gang members. At least they would be good for something.

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  3. You are the other reason comments should be disabled. Do you really think university researchers are going to amputate a monkey hand in order to do this experiment?

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  4. Using monkeys is rather cruel. They do have feelings, fear, pain, etc.

    Now using Republicans, especially from Congress, no worries as they lack real, healthy emotions. Finally a good use for them!

    :^)

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  5. They don’t have to amputate anything. They can put the monkey’s arm in a contraption that conceals it and have the monkey trained to respond to finger touches.
    Then, instead of actually touching the finger, they stimulate the brain and the monkey should respond as normal if it works.

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  6. I worked in a prosthetic clinic for a while, here’s the deal; technology like this is a dead end. The people I worked with, who had been in the field for years, just rolled their eyes at announcements like these. The problem is robotic artificial limbs cannot hold up to what humans dish out and they are obscenely expensive; a simple leg can go for $30,000 a motorized arm $90,000. One of my superiors related a story of an amputee that worked in the industry who tested a new arm/hand by putting it through a day of simple gardening; results?: Tens of thousands of dollars damage in a matter of hours doing what a human paw can suffering a few scuffs. I found that the people I worked with were hoping for stem cells and genetic engineering to put them out of business; in the end jerry rigging human bodies with carbon fiber and titanium doesn’t work as well as we’d like to imagine and watching people struggle with that junk is sad.

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  7. At Nick Meinzer
    Less than 40 years ago a computer less powerful than your phone cost more than those quotes you gave (not even allowing for inflation) but they persisted and now almost every body has a computer.
    People probably said something similar about efforts to invent the wheel about 5500 years ago – thankfully they were ignored too.

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  8. They have prosthetic hands now that can feel touch. They plant sensors in your arm attached to your nerves. The hand can tell the difference between a feather and sandpaper, hot and cold, and tell which finger you are touching. No need for the brain implants.

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