4 ms·

Gliosis is a big problem for sure, and the central nervous system's scarring is not well understood at this time. Typically with recording electrodes you can e

by Balgair 10y ago

Gliosis is a big problem for sure, and the central nervous system's scarring is not well understood at this time. Typically with recording electrodes you can either 'jiggle' them to shake off the scarring cells or pass a small amount of current between the combined electrodes to kill off the cells. These recording electrodes are typically only a few microns apart, so long range damage is a non-issue if the subject is not connected to ground in another way. You can go for ~6 months like this before the gliosis really builds up, and honestly, by that time the recording electrode has probably broken anyway or the subject has bonked the implant and it broke that way too, or as is typically the case with monkey subjects, it tore out the implant and ate it, stabbed another monkey with it, or tried to have sex with it. Monkey studies are rare and hard, not just because of ethical issues, but because monkeys are clever little assholes.

sandworm101 10y ago
The process of refreshing an electrode sounds tortuous for the subject. And your information re monkeys clawing out devices Jurassic Park-style is equally disturbing. This points to the conclusion that the efforts spent internalizing the system has less to do with benefit and more to do with preventing the animal from ending the agony. But speaking of the electrodes, how long do they last in human subjects? Docs have been implanting various electrodes in human nerves/brains for decades and I assume a paralyzed person in a research study isn't going to rip them out. With enough current can the gliosis be overcome perpetually? (lol, spellcheck went with 'parallelized' and 'gigolos'. That might say something about my normal writing subjects.)
- Balgair 10y ago
  Well, there are no pain neurons inside of the central nervous system, so they literally cannot feel anything when you record or 'clean' the tips of the electrodes. Besides, since electricity takes the least impediant path, the current can only flow locally, i.e. over the non-sensing scarring cells. There is not harm to the subject, only to the scar tissue. Human electrodes can last a lifetime if they are properly done. Look at a pace-maker. They last decades. Granted they are not for individual neuron recordings, but they work great. The first deep brain stimulation patients are about 5 years old now and they seem to be doing fine as a whole, the Parkinson's disease symptoms are significantly lessened and their quality of life is very improved. It'll take more time and effort, but yeah, I think we can overcome the gliosis, though it is probably gong to be a drug interaction with the mechanical/electrical that will do it, not just electrical alone.
biofox 10y ago
See the paper in my other reply to the parent. Admittedly, it only solves the technical problems (and only in mice so far), but it's a big step forward.

by Balgair 10y ago

sandworm101 10y ago

The process of refreshing an electrode sounds tortuous for the subject. And your information re monkeys clawing out devices Jurassic Park-style is equally disturbing. This points to the conclusion that the efforts spent internalizing the system has less to do with benefit and more to do with preventing the animal from ending the agony. But speaking of the electrodes, how long do they last in human subjects? Docs have been implanting various electrodes in human nerves/brains for decades and I assume a paralyzed person in a research study isn't going to rip them out. With enough current can the gliosis be overcome perpetually? (lol, spellcheck went with 'parallelized' and 'gigolos'. That might say something about my normal writing subjects.)

Balgair 10y ago
Well, there are no pain neurons inside of the central nervous system, so they literally cannot feel anything when you record or 'clean' the tips of the electrodes. Besides, since electricity takes the least impediant path, the current can only flow locally, i.e. over the non-sensing scarring cells. There is not harm to the subject, only to the scar tissue. Human electrodes can last a lifetime if they are properly done. Look at a pace-maker. They last decades. Granted they are not for individual neuron recordings, but they work great. The first deep brain stimulation patients are about 5 years old now and they seem to be doing fine as a whole, the Parkinson's disease symptoms are significantly lessened and their quality of life is very improved. It'll take more time and effort, but yeah, I think we can overcome the gliosis, though it is probably gong to be a drug interaction with the mechanical/electrical that will do it, not just electrical alone.

biofox 10y ago

See the paper in my other reply to the parent. Admittedly, it only solves the technical problems (and only in mice so far), but it's a big step forward.