Science fiction? Perhaps not for very much longer. Brain implants today are where laser eye surgery was several decades ago. They are not risk-free and make sense only for a narrowly defined set of patients—but they are a sign of things to come.
Unlike pacemakers, dental crowns or implantable insulin pumps, neuroprosthetics—devices that restore or supplement the mind's capacities with electronics inserted directly into the nervous system—change how we perceive the world and move through it. For better or worse, these devices become part of who we are. (...)
Today, effective brain-machine interfaces have to be wired directly into the brain to pick up the signals emanating from small groups of nerve cells. But nobody yet knows how to make devices that listen to the same nerve cells that long. Part of the problem is mechanical: The brain sloshes around inside the skull every time you move, and an implant that slips by a millimeter may become ineffective.
Another part of the problem is biological: The implant must be nontoxic and biocompatible so as not to provoke an immune reaction. It also must be small enough to be totally enclosed within the skull and energy-efficient enough that it can be recharged through induction coils placed on the scalp at night (as with the recharging stands now used for some electric toothbrushes).
These obstacles may seem daunting, but many of them look suspiciously like the ones that cellphone manufacturers faced two decades ago, when cellphones were still the size of shoeboxes. Neural implants will require even greater advances since there is no easy way to upgrade them once they are implanted and the skull is sealed back up.
But plenty of clever young neuro-engineers are trying to surmount these problems, like Michel Maharbiz and Jose Carmena and their colleagues at the University of California, Berkeley. They are developing a wireless brain interface that they call "neural dust." Thousands of biologically neutral microsensors, on the order of one-tenth of a millimeter (approximately the thickness of a human hair), would convert electrical signals into ultrasound that could be read outside the brain.
The real question isn't so much whether something like this can be done but how and when. How many advances in material science, battery chemistry, molecular biology, tissue engineering and neuroscience will we need? Will those advances take one decade, two decades, three or more? As Dr. Maharbiz said in an email, once implants "can be made 'lifetime stable' for healthy adults, many severe disabilities…will likely be chronically treatable." For millions of patients, neural implants could be absolutely transformative.
by Gary Marcus and Christof Koch, WSJ | Read more:
Image: Getty
