Transhumanism, the quest to improve both human biology and psychology through the focused, unflinching application of technology, freaks a lot of people out. I think that comes largely from the fact that when you start making it impossible for people to ignore the oddly interchangeable nature of biology and technology, it reminds them that their perception is not quite what it seems to be.
Dustin Tyler of Case Western University makes this point very well in explaining a new bionic sensing technology: “Perception occurs in the brain, not in the hand itself, so losing the limb is really just losing the switch that turns the sensation on or off.” Tyler and his team have created a complex new set of switches in the form of a revolutionary new bionic replacement hand — and they can do a lot more than just turn those switches on or off.
The achievement begins in the neurons of the patient’s arm. Igor Spetic, an amputee who lost his hand in an industrial accident several years ago, let the researchers attach a complex assortment of electrodes to the remainder of certain nerves that had once been bound for the hand. By stimulating these nerves at different points, they create sensations in the brain that are distinguishable by the patient. It’s important to note that while the physical sensations felt as a result of these electrodes are every bit as real as those felt as a result of regular sensation, the impulses did not at first correspond to any particular sensation. So, only with time and training did Spetic come to associate one stimulation with the tip of his forefinger, another with the tip of his middle finger, and so on.
That might sound like it would be slow, but we are literally built from the reptile brain up to unconsciously translate neural signals into subjective perceptions; it’s remarkable how quickly patients (in this study and in many before it) have been able to integrate totally novel neural signals as normal incoming sensations. At first it takes effort to remember the association between a particular feeling and a particular finger, but soon the brain adjusts to the idea that a particular finger simply feels a particular way. Once that happens, a bionic signal is really no more difficult to perceive with than a normal one, though right now it still has far lower fidelity overall.
This sort of detail work requires more nuance than past prosthetics could provide.
This approach has actually existed for a while under the name targeted muscle reinnervation, and this team took that technology one step further by incorporating complex patterns of nerve excitation. Rather than simple on-off switching, the team made a bionic sensor that could distinguish between different textures, and send the brain a distinctive pattern of excitation to go with it. Again, this is basically exactly how the brain does it; neither a real hand nor a bionic one has a specific “rough surface” spot to switch on or off in the brain, but rather an ability to interpret patterns of on-off switching in one or multiple sensory areas.
This has the exciting implication that, once basic sensory locations had been mapped out, bionic signals might be interpretable without training; a rapid collection of small, semi-random excitations of the tip of a finger might be able to be interpreted as roughness even if the patient has never felt that particular texture before. To be clear, though, that’s further than this study goes. As Tyler points out, it’s still necessary to do basically what a baby does when learning to make sense of the world, constantly inspecting things to associate real objects with sensations.
In the video above, you can see the small but jarring detail that Spetic’s hand is sitting a few inches from his arm while he feels through it. Again, this gets at our ideas of what it means to be human and to experience the world. That hand could have been on the other side of the Earth, its signals transmitted via the Internet, or the sensors could been replaying sensations recorded several days earlier. Both of these scenarios would create a feeling of hand-use every bit as real as if the prosthetic had been strapped to the arm and painted to look like flesh.
TED recently hosted this incredible dancing demonstration of a bionic leg.
Obviously, veterans and other amputees are by far the highest priority in applying technology such as this, but we should also pay attention to the incredible array of other possible applications, both positive and negative. Spetic’s phantom pain almost completely subsided with the reintroduction of sensible signals to that portion of his brain, and of course the extra-curricular applications of feeling things without needing to be physically next to them ought to be… obvious. (I’m talking about sex…)
Could we start preserving sensations for posterity? Imagine if you your local library had, along with Oliver Twist and Glengarry Glen Ross, recordings of the handshake of an ex-President, the smell of the Vatican in 2015, or the feeling of petting the last living snow leopard. The advance of non-invasive neural stimulation (read: little or no surgery required) means we really are entering a time when such things may become possible and widespread. This study is just one of many which collectively herald the beginning of the neural age, but its refined, nuance-focused approach to bionics could still be the beginning of a whole new era in neural interfacing. And that would mean a whole new era for mankind.
