edited February 2016 in Coatings, transdermals, other implants
So, one of the technologies I've been researching while working on my BCI, is the interception of action potentials in a manner that's reversible and doesn't require you to perform a nerve block with anesthetic every time you want to do it. In order to achieve effective immersion, without interference from ambient stimuli, and get the most of a virtual reality experience, this is kind of a must. So, I turned to electrical nerve blocks. In my research thus far, electrodes have always been placed on the nerve itself. However, logic dictates that if I use skin-contact electrodes, and place them far enough apart, and run enough current through them, the same results can be achieved.
I've almost got everything I need to do a test of my theory together, I just need to finish assembling my electrodes, acquire a decent AC signal generator, and figure out how to hold everything in place. I'll be attempting to block the radial, median, and ulnar nerves in my left arm starting from just below my elbow, since the nerves are closer to the surface of the skin there. I'll probably attempt to do a cathodic block with DC while I wait on the AC signal generator, but based on the numbers I've seen, which label the skin as a 1000 ohm resistor when wet, I'm looking at 3000 ohms of resistance. According to one study, a human sacral nerve was blocked with a current of 7 mA applied directly to the nerve, and since the current saturation of the tissue of the body behaves in a uniform way the further you move from the electrode, I estimated that 20 mA's would be sufficient to block the nerves without direct contact. Using Ohm's law, that puts me at 60 volts.
Don't forget to put in all of the redundant failsafe and thresholds. ^^
It's like estimating that by running 200 volts on the walls I'll end up charging my phone.
The human skin model for normal skin is in the megaohms, but still.
Better redundant than something stupid happening. c_c
I can't give you a definite answer of yes or no, I would expect it to go badly though, working with the two's heat tolerance differences. >~<
Basically you have different fiber types carrying the impulses communicating pain. There are fibers related to chronic pain.. the stuff we describe as aching and dull and hard to locate exactly.. and fibers related to sharp, stabbing, acute pain. Your body has a preexisting relationship between these fibers... acute pain basically down regulates chronic. This is (partially) why massage works.. if you are sore and you get a deep painful massage, it relieves some of the aching dull pain for a period. So, a TENS unit activates the fibers in a way that results in muffling of the chronic pain fibers.
For a pain source you might try capsaicinoids... a small scratch (or sensitise the skin with a little and paper) and a drop of hot sauce (or rub with a small red chilli/pepper) will give you a reasonable level of pain with no real damage to you and no interference with your device. Wash with soap and alcohol when your done.
Also you can buy a pack of TENS pads online (ebay?) for a few dollars, and they conduct pretty well, they can be re-used too if you clean the skin well before you apply them, plus they adhere, so no need for any special rigging to keep them in place.