21 February 2009

We Are All Cyborgs Now: Photoelectrode Control

A fascinating new type of brain stimulating electrode is being developed at Case Western Reserve University. This new electrode can be triggered by light, yet it triggers a nerve action potential at the brain implantation site.
The team led by Ben W. Strowbridge and Clemens Burda coated the interiors of extremely finely drawn-out glass micropipettes with lead selenide nanoparticles. Lead selenide is a semiconductor that is activated by IR light. As in solar cells, irradiation “catapults” firmly bound electrons out of the valence band and into the conduction band of the semiconductor, where they can move freely. This leads to charge separation and thus to an electrical potential. With a suitable laser, defined processes elicited by short light pulses set off corresponding electrical pulses in the micropipette. An electrical field is thus formed around the pipette, which can then be used by the researchers to stimulate neurons in rat brain samples with a high degree of time-resolution.

...By using these new photoelectrodes, the cooperation of nerve cells can be studied. However, therapeutic applications are also possible: the probes could be used to activate individual regions of the brain or damaged or cut nerves to restore function - without the need for disturbing wires. _Physorg
Fascinating! The laser pulses are transmitted down the glass electrode to the special implanted semiconductor material, where it is transduced to an electrical potential. This potential then triggers nerve impulses -- apparently on a very fine time resolution scale.

Think about it for a moment. A cyborg could wear a fiberoptic receiver "cap", which can be activated with finely aimed laser light from some distance away, to provide the desired brain stimulus. Would it be possible to control a human brain with any degree of multi-sensory "conscious" awareness using this technique? Eventually, perhaps.

Although lasers require line of sight control, which restricts their use vis a vis RF controllers, the lack of need for surface electronics and power supply would seem to be a significan advantage for many purposes.

Cyborgs and Grobycs appear to offer far more promise than pure robotics, at this point in time. One normally thinks of military or law enforcement applications when thinking of a "six million dollar man" with external neural triggers or shutoffs. But as more is learned about the effect of brain stimulation, we are more likely to discover ways of enhancing normal brain function. At that point, the range of applications will broaden, and the waiting line of humans desiring augmentation is apt to grow rather long.

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Blogger Will Brown said...

I wonder just how effective this type of theraputic technology might be at treating less neurologically directly connected conditions like diabetes, hyper tension or gross muscle damage repair? All of these pathological conditions (and more, of course) are more or less directly influenced by cerebral or CNS functions; might there be a brain function that this technique could manipulate to stimulate more desirable insulin generation say? Gross muscle tears or incisions are already treated with electro stimulation devices, this would seem to offer the possibility for much more refined control and specific application for such therapies, I think.

Saturday, 21 February, 2009  
Blogger al fin said...

I don't know. The voltages and currents involved are very limited, so for musculoskeletal rehab, you might have to use more direct electromagnetic stimulation methods.

For diabetes, the hypothalamus detects blood sugar levels and the connected pituitary has an influence on the pancreas' insulin producing tissue. Not an easy approach. But you may be hinting at using these electrodes as a behavioural approach to lifestyle changes in type II diabetes? That may be feasible, eventually.

But then, some very potent anti-obesity drugs are in the pipeline, which should have a big impact on type II DM.

My money is on artificial islets of Langerhans implants for type I, along with advanced immune therapies.

Saturday, 21 February, 2009  

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