h a l f b a k e r yQuis custodiet the custard?
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I should register XtremeBrain as a trademark, heh heh.
Several decades ago there was a fair amount of experimentation that involved electrodes planted in the brain. Various sections like pain and pleasure centers could be remotely stimulated. Larry Niven wrote some SF stories about "wireheads"
who were addicted to the pleasure-stimulation thing. The connection gadget that plugged into their heads was called a "droud".
Alas, that sort of direct connection is not safe. The place where the hardware breaks through the skin of the body is a place where infections can get around the edges of the skin, and do damage. Constant medication is necessary to keep infections at the implant-sites under control.
Well, It Doesn't Have To Be Done That Way. Suppose a network of electrodes were implanted in various places, and all lead to a particular area UNDER the skin. A small coil at the end of each electrode, flat under the skin, is basically an antenna. And since the implants are entirely inside the body, no infections will occur after the normal surgery-recovery time.
This XtremeBrain Idea theoretically solves a problem related to "reading" brain signals, since they are being brought to the surface where antenna emissions, very-low-power though they would be, can still be detected easily with standard EEG gear. Furthermore, these are "deep brain" signals, and not just the surface signals that an EEG normally picks up.
Next, since antennas work both ways, the implanted XtremeBrain electrodes could have a signal easily INDUCED in them by an entirely external device. You could strap that device against the skull and let it induce signals in any/all of those electrodes, as appropriate. This is a MUCH lower-power approach than any other direct-brain-influencing induction technology that I've ever heard about before.
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how is a use of induced current a
reducer of required current? also, what
does "Xtreme" have to do with this? |
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this could only be powered off of
batteries that have inductors hooked up
to them [inefficiency], can't use
dielectric material effectively for flux
transmission [inefficiency], requires
rectifier implanted at each of the sites
for D.C. [space concern], has nothing to
actually attach to. |
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[tcarson], there are existing experiments that try to directly induce currents in the brain. These gadgets would consume a lot less power if an antenna/electrode system existed. PERHAPS, in the future, when much more is known about the parts of the brain to stimulate, and with more precise frequency-control of the stimulus-electronics, including perhaps focussed masers, a low-power method can be found that can work without buried antennas-electrodes. |
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Anyone wanting to undergo surgery to have their brains wired, when so much remains to be learned about interfacing the brain to the outside world, could be considered doing something Xtreme. |
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Your notion that the external stimulation-gadget can only be powered by batteries is ridiculous. A stationary one can be plugged into a wall, and a portable one could be powered by solar cells that cover a hat. |
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I'm not sure what you are getting at with respect to dielectrics. With no buried electrode, whatever problem you have, to get a signal into the brain, is going to be a more difficult problem. |
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Your nonsense about diodes is ignoring such modern thin gadgets as RFID tags, complete with an enormous number of transistors, diodes, capacitors, etc. |
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I'm not certain that stimulating the brain requires DC, especially if they are considering/experimenting with electrode-less induction (always AC, that). |
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Your statement "has nothing to attach to" is meaningless without further explanation. Induction ISN'T SUPPOSED TO have a direct attachment! |
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I'd be worried as you your sensitivity to
magnetic fields. Obviously you'd never
be able to have an MRI, but would you
ever be able to walk the through an
airport metal detector? How about ride
an electric train? |
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On the side of infection, although
you're not breaking the skin, you're still
going to have to go through the
blood/brain barrier. Doing so will
increase
your
vulneralility to brain infections. |
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[st3f], those are pretty good points. However, I do think that with a Faraday cage over your head, you could get an MRI of the rest of your body when needed. And regarding brain infections, a recent issue (I have to look up exact issue) of "Scientific American" has an article about those early electrode-planting pioneers, and in animal tests they managed to have hardwired electrodes for more than 2 years, without medical problems. Of course, that was in the lab with appropriately clean facilities and probably also with various antibiotics. Nevertheless, think a moment about that phrase: "blood brain barrier". The brain is well-supplied with blood; fully 25% of freshly oxygenated blood from the lungs goes straight to the brain. (Do some math: assume 103-pound human with 3-pound brain: 100 pounds gets 75% so 33 pounds gets 25% of oxygen. That means, pound for pound -- or gram for gram -- brain tissue can consume 11 times as much oxygen as other tissues in the body.) Anyway, the blood-brain barrier exists between the blood vessels and the brain tissue. It doesn't necessarily exist as a sheet between the skull and the brain. So, an electrode that comes through the skull and passes between blood vessels is also potentially bypassing the barrier altogether, and not damaging it. (Of course, if I'm wrong about the barrier not completely surrounding the brain, I'm sure someone will tell me in short order, heh.) |
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vernon, personal electronics work on
direct current. induction requires a
variable magnetic field. there would be
inefficiencies in the induction of current
because the coils are separated by all of
that tissue and bone, which isn't as
good for the transfering of magnetic
fields as certain dielectrics. you could
plug these into the wall, put no one will
be interested in being tethered like that
what's the point in having the implant
at all at that stage? the surface of the
head isn't large enough for a solar
panel that will power this, and solar
panels are once again d.c. you can't use
a faraday cage in an MRI because the
cage itself will set up a reciprocal
current through induction and effect the
implants. when i said that there was
nothing to connect these implants to, i
was saying that we have no inputs for
them. you'll have functioning brain links
that don't have any purpose. how the
hell am i ignoring things like rfid and
thin electronics? |
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tcarson: I think Vernon intends the coils
to be immediately subdural so that they
will effecively pick up an AC current
from a similar coil held to the outside of
the head. This current is then delivered
to the centre of the brain via the
implant. The simplest version of this
would just involve an open loop of wire
with the insulation stripped off that the
ends. Thes ends would then be inserted
where you want to deliver the jolt. |
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Vernon. I'm fairly certain that the
blood-brain barrier covers the brain
completely, but the optic nerves and
spine have to come out somewhere. |
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The MRI was a pretty flippant comment
as I don't think a person with a metal
implant of any kind can have an MRI.
Not certain, though. It might only be
ferromagentic materials. |
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Not having any idea of the sensitivity of
the brain to small currents, I wonder if
you'd get a buzz just by spinning
yourself around in the Earth's magnetic
field. Guess not. |
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This is pretty well baked.
1: Stuff is implanted in the brain all the time. [V] is right in that it can be made safer if the overlying skin is intact.
2: [st3f] - you can have an MRI with metal. Consider: fake hip. It just cannot be ferrous.
3: Below is a chunk of text cut from a scholarly journal article which I do not think is freely available on line. People undergo essentially what [V] described, but to control seizures. |
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Electrical Stimulation of the Anterior Nucleus of the Thalamus for the Treatment of Intractable Epilepsy
*John F. Kerrigan et al. Epilepsia
Volume 45 Page 346 - April 2004 |
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The intracranial stimulation leads were Medtronic 3387 DBS Medtronic, (Minneapolis, MN, U.S.A.) depth electrodes with 4 platinum–iridium stimulation contacts (each contact 1.5 mm wide with 1.5 mm edge-to-edge separation). Stimulation lead implantation was achieved by using a CRW stereotactic frame. Target sites were selected from magnetic resonance (MR) images, by using 1-mm-thick axial, coronal, and sagittal spoiled gradient echo (SPGR) pulse sequences. The target site (ANT) was identified on each side by visual selection, with reference to a standard stereotactic atlas (9). |
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During surgery, a guide cannula was inserted through a burr hole, and advanced to a point 10 mm from the desired target. In three of five patients, a monopolar single-unit recording electrode (Advanced Research Systems, Atlanta, GA, U.S.A.) was initially introduced to confirm the anatomic depth for entry into thalamic tissue after traversing the lateral ventricle (Fig. 1). The electrode tip was initially positioned within the lateral ventricle, where no units were recorded, then advanced until units were first recorded (superficial surface of ANT), and then advanced until units ceased (intralaminar region) and then recommenced [dorsomedian (DM) nucleus of thalamus]. The single-unit recording electrode was removed, and a temporary stimulation lead (Radionics Stimulation/Lesioning Probe, Burlington, MA, U.S.A.) was then introduced to elicit the driving response (see later). This was then removed, and the Medtronic 3387 DBS stimulation lead, with an internal stylet, was then inserted through the guide cannula to the desired target. The stylet and cannula were then withdrawn under fluoroscopy, after test stimulation demonstrated no adverse events. |
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The programmable pulse generators (Medtronic 7424 ITREL II Pulse Generator, Medtronic, Minneapolis, MN, U.S.A.) were surgically placed into a subcutaneous pocket in the subclavicular region and connected to the stimulation leads by means of a lead extension (Medtronic 7495 Lead Extension, Medtronic, Minneapolis, MN, U.S.A.), which was tunneled under the skin of the neck and scalp. Electrically independent pulse-generation systems were placed on each side (i.e., bilateral ANT implantation). Placement location of the stimulation leads was confirmed with either cranial computed tomography (CT; n = 1) or MR imaging (n = 4) (Fig. 2). |
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There are also recently invented nanowires (piezo-electric??) if anyone's read about them. Theyre expected to be able to power medical implants through kineses of your body. Would make the concept of a powered permanently implanted device plausible.... |
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[bungston], thanks. I was thinking that the XtremeBrain Interface idea would involve a LOT more electrodes than what they are doing to stop seizures. It would be nice if enough I/O could be accommodated for direct mental control of external hardware (and lots less biofeedback training that is currently assumed would be associated with noninvasive external EEG-type sensors). |
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Uuuummmmm... sorry man it has too many flaws and it sounds to apple like... |
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