Neuroscientist Rudolfo Llinas and his colleagues envision an entire array of nanowires being connected to a catheter tube, which could then be guided through the circulatory system to the brain. Once there, the nanowires would spread into a kind of bouquet, branching out into tinier and tinier blood vessels until they reached specific locations. Each nanowire would then be used to record the electrical activity of a single nerve cells, or small groups of nerve cells.
The nanowires would be very small as compared to the thickness of capillaries.
Writing in the July 5, 2005, online issue of The Journal of Nanoparticle Research, the researchers explain it is becoming feasible to create nanowires far thinner than even the tiniest capillary vessels. That means nanowires could, in principle, be threaded through the circulatory system to any point in the body without blocking the normal flow of blood or interfering with the exchange of gasses and nutrients through the blood-vessel walls.
The team describes a proof-of-principle experiment in which they first guided platinum nanowires into the vascular system of tissue samples, and then successfully used the wires to detect the activity of individual neurons lying adjacent to the blood vessels.
Rodolfo R. Llinás of the New York University School of Medicine led the team, which included Kerry D. Walton, also of the NYU medical school; Masayuki Nakao of the University of Tokyo; and Ian Hunter and Patrick A. Anquetil of the Massachusetts Institute of Technology.
Nanowires that can receive electrical signals can also be set up to send signals.
"In this case, we see the first-ever application of nanotechnology to understanding the brain at the neuron-to-neuron interaction level with a non-intrusive, biocompatible and biodegradable nano-probe," said Roco. "With careful attention to ethical issues, it promises entirely new areas of study, and ultimately could lead to new therapies and new ways of treating diseases. This illustrates the new generations of nanoscale active devices and complex nanosystems."
Likewise, the nanowire technique could greatly improve doctors' ability to pinpoint damage from injury and stroke, localize the cause of seizures, and detect the presence of tumors and other brain abnormalities. Better still, Llinás and his coauthors point out, the nanowires could deliver electrical impulses as well as receive them. So the technique has potential as a treatment for Parkinson's and similar diseases.
Picture an embedded nanotech computer wired up to feed the mind information as images, sounds, or simply thoughts that suddenly happen. At the extreme the nanowires could be used to take over a person and control them. Picture a "Manchurian Candidate" controlled by a foreign power. Or picture criminals whose nanocomputers monitor their thoughts and send inhibiting messages that prevent violent acts and other forbidden behavior.
Using embedded nanowire sensors to make sense of complex thoughts in brains will remain hard to do for years to come. But I predict that identification of some basic emotions or urges will be easier to accomplish. Once reactive loops to suppress emotions such as hostility or sexual desire reach technical feasibility consider the issues we'll face. Should rapists or pedophiles up for parole be required to submit to nanowire circuitry implants that suppress their sexual desires? One can even imagine a home surveillance system where the parolee can get their sexual desires unlocked only if they present a willing adult to a video camera hooked up to a police station. A parolee's sexual desires could even get automatically deactivated using a GPS monitoring device that activates as they leave home. Or a home transmitter that unblocks their sexual desire circuits could have a reach of only, say, 50 feet around their house and as they move away they lose the signal that allows their sexual desires to work.
Repressive regimes could use embedded nanowire circuits to ensure obedience or as interrogation tools to activate a person's memories and force them to talk. On the bright side embedded nanowires could enable viewing of movies or listening without any external device to carry along. One could have an embedded internet link to allow one to think search requests. I'm reminded of the movie The President's Analyst where "The Phone Company" kidnaps James Coburn's character to try to convince him to advise the President of the United States to support embedding electronic phone circuits in everyones' brains. I'm also reminded of the Stargate SG-1 Goauld that take over the brains of humans that they enter into.
Ramez Naam's book More Than Human has a treatment of Llinas's proposal as well. He covers the wider issue of brain-computer interfaces in his chapter The Wired Brain. Some of what he writes about neurobiology research was news to me when I read it. Another good book to read at the same time is Joel Garreau's book Radical Evolution.
|Share |||Randall Parker, 2005 July 10 02:56 PM Nanotech for Biotech|