Here’s an update for those of you who, like me, eagerly await the availability of your cyberpunk implant suite – experiments with using silk as a substrate for miniaturised electronic circuits show that they can integrate with animal body tissue without any adverse effects or biological rejection. [via NextBigFuture; image by Automatomato] Which means we can not only make better neural interfaces, but aesthetic gadgets like LED ‘tattoos’ to live under our skin:
To make the devices, silicon transistors about one millimeter long and 250 nanometers thick are collected on a stamp and then transferred to the surface of a thin film of silk. The silk holds each device in place, even after the array is implanted in an animal and wetted with saline, causing it to conform to the tissue surface. In a paper published in the journal Applied Physics Letters, the researchers report that these devices can be implanted in animals with no adverse effects. And the performance of the transistors on silk inside the body doesn’t suffer.
The biocompatibility of silicon is not as well established as that of silk, though all studies so far have shown the material to be safe. It seems to depend on the size and shape of the silicon pieces, so the group is working to minimize them. These devices also require electrical connections of gold and titanium, which are biocompatible but not biodegradable. Rogers is developing biodegradable electrical contacts so that all that would remain is the silicon.
The group is currently designing electrodes built on silk as interfaces for the nervous system. Electrodes built on silk could, Litt says, integrate much better with biological tissues than existing electrodes, which either pierce the tissue or sit on top of it. The electrodes might be wrapped around individual peripheral nerves to help control prostheses. Arrays of silk electrodes for applications such as deep-brain stimulation, which is used to control Parkinson’s symptoms, could conform to the brain’s crevices to reach otherwise inaccessible regions. “It would be nice to see the sophistication of devices start to catch up with the sophistication of our basic science, and this technology could really close that gap,” says Litt.
In other words, we’ve pretty much got the hardware capability to interface machines and computers with our brains and nervous systems, what with these silk circuits for basic actuators and the previously-mentioned optogenetic technologies for deep duplex information channels. Now all we need to do is reverse-engineer the nervous system’s protocols and write a programming manual for the human brain… simple, right?
There’s a lengthy but interesting piece up over at Wired about the relatively young discipline of optogenetics – the science of isolating and communicating with specific types of neuron using light. The discovery of the process is an interesting story in its own right, but the really futurismic bit is the implication tucked into the final few paragraphs:
Optogenetics has amazing potential, not just for sending information into the brain but also for extracting it. And it turns out that Tsien’s Nobel-winning work — the research he took up when he abandoned the hunt for channelrhodopsin — is the key to doing this. By injecting mice neurons with yet another gene, one that makes cells glow green when they fire, researchers are monitoring neural activity through the same fiber-optic cable that delivers the light. The cable becomes a lens. It makes it possible to “write” to an area of the brain and “read” from it at the same time: two-way traffic.
Why is two-way traffic a big deal? Existing neural technologies are strictly one-way. Motor implants let paralyzed people operate computers and physical objects but are incapable of giving feedback to the brain. They are output-only devices. Conversely, cochlear implants for the deaf are input-only. They send data to the auditory nerve but have no way of picking up the brain’s response to the ear to modulate sound.
No matter how good they get, one-way prostheses can’t close the loop. In theory, two-way optogenetic traffic could lead to human-machine fusions in which the brain truly interacts with the machine, rather than only giving or only accepting orders. It could be used, for instance, to let the brain send movement commands to a prosthetic arm; in return, the arm’s sensors would gather information and send it back.
Science fiction has been talking about the brain-machine interface for decades, but usually in terms of splicing the hardware into the nervous sytem in much the same way as connecting up a regular electronic circuit, and with little experimental evidence for its viability. As Chorost points out in the Wired piece, we’re not going to see commercially available optogenetic interfaces for some time yet, but this proof-of-concept work suggests it really is only a matter of time before we do. [image by LoreleiRanveig]
More progress has been made in the field of artificial telekinesis by researchers at University of California, who have shown that the brains of macacque monkeys can learn how to manipulate a prosthetic through thought alone:
…macaque monkeys using brain signals learned how to move a computer cursor to various targets. What the researchers learned was that the brain could develop a mental map of a solution to achieve the task with high proficiency, and that it adhered to that neural pattern without deviation, much like a driver sticks to a given route commuting to work.
“The profound part of our study is that this is all happening with something that is not part of one’s own body. We have demonstrated that the brain is able to form a motor memory to control a disembodied device in a way that mirrors how it controls its own body. That has never been shown before.”
This is an exciting development. Developing the means to control prosthetics as if they were part of your own body would improve the lives of paraplegics, and even offer the possibility of extending baseline human abilities.
[from Physorg, via KurzweilAI][image from Physorg]
A fascinating article in New Scientist on neural prosthesese and the possibility of a new source of inequality: between those who can afford to pay for technological mental enhancements and those who cannot:
People without enhancement could come to see themselves as failures, have lower self-esteem or even be discriminated against by those whose brains have been enhanced, Birnbacher says. He stops short of saying that enhancement could “split” the human race, pointing out that society already tolerates huge inequity in access to existing enhancement tools such as books and education.
The perception that some people are giving themselves an unfair advantage over everyone else by “enhancing” their brains would be socially divisive, says John Dupré at the University of Exeter, UK. “Anyone can read to their kids or play them music, but put a piece of software in their heads, and that’s seen as unfair,” he says. As Dupré sees it, the possibility of two completely different human species eventually developing is “a legitimate worry”.
But the news is not all bad, with the observation that the human brain is becoming ever more plastic and capable of adaptation:
Today, our minds are even more fluid and open to enhancement due to what Merlin Donald of Queens University in Kingston, Ontario, Canada, calls “superplasticity”, the ability of each mind to plug into the minds and experiences of countless others through culture or technology. “I’m not saying it’s a ‘group mind’, as each mind is sealed,” he says. “But cognition can be distributed, embedded in a huge cultural system, and technology has produced a huge multiplier effect.”
It is interesting to speculate what the long-term consequences of dense technological interconnectedness will be on the human condition. Even assuming actual precise neuroengineering proves difficult, neural prosthesese offer a world of opportunity.
[via KurzweilAI][image from n1/the larch on flickr]
Sven Johnson returns with another dispatch from the world just around the corner. This month, he’s watching the new ambassadors of transhumanism – wheelchair-bound cyber-centenarians totally pwning the kids in pro video game leagues.
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