sábado, 20 de marzo de 2010

Brain Implants

Brain Implants
In a Kurzweillian future, the world would become a very strange place, where converging advances in nanotechnology, biotechnology and computer science combine to propel humanity to its next stage of evolution. "By the end of this century, I don't think there will be a clear distinction between human and machine," Kurzweil told the Foresight Institute's Eighth Conference on Molecular Nanotechnology.
[By 1969,] the miracle of giving light to the blind i, ii, iii, iv or sound to the deaf ha[d] been made possible by implantation of electrodes, demonstrating the technical possibility of circumventing damaged sensory receptors by direct electrical stimulation of the nervous system. Computers that become part of our bodies are not so far-fetched.… Surgeons have performed [more than 50,000 ] cochlear implants on patients with hearing loss.v "These people are already walking around with chips in their heads," [Peter Cochrane, head of research at British Telecommunications PLC,] says.
Giving completely paralyzed patients full mental control of robotic limbs or communication devices has long been a dream of those working to free such individuals from their locked-in state. There is little doubt that direct brain-machine interfaces will be available in the very near future.

Researchers at the University School of Medicine in Philadelphia demonstrated that signals from neuron groupings in rats brains can be used to control a physical device without the rats carrying out a physical action themselves. "This study breaks new ground in several areas," said Dr. Eberhard Fetz, Department of Physiology and Biophysics, University of Washington School of Medicine, who authored a commentary on the research in the "News and Views" section of Nature Neuroscience. "Unlike comparable studies, this is the first demonstration to prove that simultaneous recordings from large ensembles of neurons can be converted in real time and online to control an external device. Extracting signals directly from the brain to control robotic devices has been a science fiction theme that seems destined to become fact."
[Miguel Nicolelis and colleagues] at Duke University in North Carolina wired monkey brains to control robotic arms that mimicked the motions of their real arms (another search; see also another similar study). "It was an amazing sight to see the robot in my lab move, knowing that it was being driven by signals from a monkey brain at Duke," said [Massachusetts Institute of Technology's] Touch Lab director and co-researcher Mandayam Srinivasan. "It was as if the monkey had a 600-mile- (950-km-) long virtual arm."

John P. Donoghue, a neuroscientist at Brown University developing a similar system, said paralyzed patients would be the first to benefit by gaining an ability to type and communicate on the Web, but the list of potential applications is endless, he said. The devices may even allow quadriplegics to move their own limbs again by sending signals from the brain to various muscles, leaping over the severed nerves that caused their paralysis.

Both he and Nicolelis hope to get permission from the Food and Drug Administration to begin experiments in people [in 2004]. Nicolelis also is developing a system that would transmit signals from each of the hundreds of brain electrodes to a portable receiver, so his monkeys — or human subjects — could be free of external wires and move around while they turn their thoughts into mechanical actions.
Scientists say they have developed a technology that enables a monkey to move a cursor on a computer screen simply by thinking about it.… Using high-tech brain scans, the researchers determined that [a] small clump[] of cells…were active in the formation of the desire to carry out specific body movements. Armed with this knowledge, [researchers at the California Institute of Technology in Pasadena] implanted sensitive electrodes in the posterior parietal cortex of a rhesus monkey trained to play a simple video game.… A computer program, hooked up to the implanted electrodes,…then moved a cursor on the computer screen in accordance with the monkey's desires — left or right, up or down, wherever "the electrical (brain) patterns tells us the monkey is planning to reach," according to [researcher Daniella] Meeker. [Dr. William Heetderks, director of the neural prosthesis program at the National Institute of Neurological Disorders and Stroke,] believes that the path to long-lasting implants in people would involve the recording of data from many electrodes. "To get a rich signal that allows you to move a limb in three-dimensional space or move a cursor around on a screen will require the ability to record from at least 30 neurons," he said.

Dr. Philip R. Kennedy, an [sic] clinical assistant professor of neurology at Emory University in Georgia, reported that a paralyzed man was able to control a cursor with a cone-shaped, glass implant (See also another similar study). Each [neurotrophic electrode] consists of a hollow glass cone about the size of a ball-point pen tip. The implants…contain an electrode that picks up impulses from the nerve endings. Before they are implanted, the cones are coated with chemicals — taken from tissue inside the patients' own knees — to encourage nerve growth. The implants are then placed in the brain's motor cortex — which controls body movement — and over the course of the next few months the chemicals encourage nerve cells to grow and attach to the electrodes. A transmitter just inside the skull picks up signals from the cones and translates these into cursor commands on the computer.16
Scientists at Northwestern University crafted a two-wheeled robot that operated partly on the electrical signals of a displaced lamprey's brain (pic, video). The part of the brain used in the experiment normally keeps the lamprey upright in the water. When connected up correctly, the organ can guide the robot towards a light source.
Scientists at the University of Tokyo are exploring ways that la cucaracha can become more socially redeeming. Using hardy American roaches, scientists remove their wings, insert electrodes in their antennae (more pics, schematics) and affix a tiny backpack of electric circuits and batteries to their carapace. The electrodes prod them to turn left and right, go backward and forward. The plan is to equip them with minicameras or other sensory devices vi [Later that same year, the motion picture The Fifth Element (1997) featured a remote-controlled cockroach equipped with a camera.]

Scientists at the Max Planck Institute have…demonstrated electronic-based neuron transistors that can control the movement of a live leech from a computer. They can detect the firing of a nearby neuron, cause it to fire, or suppress a neuron from firing — all of which amounts to two-way communication between neurons and neuron transistors.
Rats steered by a computer…could soon help find buried earthquake victims or dispose of bombs, scientists said [1 May 2002]. The remote-controlled "roborats" (more pics, audio, video) can be made to run, climb, jump or turn left and right through electrical probes, the width of a hair, implanted in their brains. Movement signals are transmitted from a computer to the rat's brain via a radio receiver strapped to its back. One electrode stimulates the "feelgood" center of the rat's brain, while two other electrodes activate the cerebral regions which process signals from its left and right whiskers. "They work for pleasure," says Sanjiv Talwar, the bioengineer at the State University of New York who led the research team.… "The rat feels nirvana."  Asked to speculate on potential military uses for robotic animals, Dr Talwar agreed they could, in theory, be put to some unpleasant uses, such as assassination.
Maria. Gabriela Medina Maldonado
C.I. 16779553

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