Monkeys with touch-sensitive prosthetic arms sound like something out of science fiction, but they're real.

The new development is a major breakthrough. The touch-sensitive limbs may one day convey sensory information to amputees directly.

In a press release, the scientists, funded by DARPA, said,

"To restore sensory motor function of an arm, you not only have to replace the motor signals that the brain sends to the arm to move it around, but you also have to replace the sensory signals that the arm sends back to the brain."  

Sliman Bensmaia, one of the researchers, said in the press release. "We think the key is to invoke what we know about how the brain of the intact organism processes sensory information, and then try to reproduce these patterns of neural activity through stimulation of the brain."

The scientists conduced a series of experiments with monkeys and identified patterns of neural activity that occur while they manipulate objects. They induced the same neural patterns in a prosthetic hand via electric shock, and the monkeys responded the same way they would have if they had really felt the contact.

 "If you really want to create an arm that can actually be used dexterously without the enormous amount of concentration it takes without sensory feedback, you need to restore the somatosensory feedback," explains Sliman Bensmaia, a professor at the University of Chicago.

They described their research  on the monkeys as follows:

"The researchers performed a series of experiments with rhesus macaques that were trained to respond to stimulation of the hand. In one setting, they were gently poked on the hand with a physical probe at varying levels of pressure. In a second setting, some of the animals had electrodes implanted into the area of the brain that responds to touch. These animals were given electrical pulses to simulate the sensation of touch, and their hands were hidden so they wouldn't see that they weren't actually being touched.

Using data from the animals' responses to each type of stimulus, the researchers were able to create a function, or equation, that described the requisite electrical pulse to go with each physical poke of the hand. Then, they repeated the experiments with a prosthetic hand that was wired to the brain implants. They touched the prosthetic hand with the physical probe, which in turn sent electrical signals to the brain."

And, in the end, the monkeys couldn't distinguish between actual flesh and robotic stimulus. This means we may be able to develop artificial limbs with a sense of touch.

 "This is the first time as far as I know where an animal or organism actually perceives a tactile stimulus through an artificial transducer," says the professor. "It's an engineering milestone."

While not likely to result in monkey butlers-more, well, help war victims and amputees-the find is a major breakthrough. Human trials may begin as soon as within the next year.

What do you think of this? Are you worried or excited by the idea? Sound off below!