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_AlreadyTaken_ t1_j46u0oi wrote

Reply to comment by mckulty in When nerve damage occurs, where is the pain perceived? at the site of damage or at the end of the nerve? by menooby

I read about phantom limbs and it seems that the brain expects noise from nerve fibers. It normally ignores this noise and considers it just a nerve fiber at rest. When the nerve is cut now there is no noise but there is no signal either. Without noise something must be happening but what? So the brain fills in the blank.

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ThatOtherGuy_CA t1_j470iwd wrote

Seems like an evolutionary side effect that would normally be beneficial. Pinching a nerve for a prolonged time isn’t good, so when your brain loses feeling to an area it gives you pain signals to trigger you into moving, so that you don’t sleep or sit in a way that could lead to paralysis, and once it gets other feedback it stops.

Unfortunately it can’t tell the difference between a pinched nerve and a lost limb, so it’s instead like “bro move your hand, bro, BRO!!!” And now your left hand that’s been missing for 6 years is suddenly on fire.

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Rombolio t1_j46ul2d wrote

I work with a pain doc that is an anesthesiologist and they've done sympathetic blocks to help with phantom limb. They've had varying success, but sometimes "shutting off" the nerve resets it. We do a lot for CRPS from crush injuries in the feet.

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_AlreadyTaken_ t1_j46v8e4 wrote

Check out Oliver Sacks' writing on phantom limbs, it is very interesting. One guy had a prosthetic limb. It seems to get agile with a prosthetic you need this phantom limb effect. So this guy had to make his "appear" by slapping the leg stump and he could make it turn on. Some people even have severe pain in the phantom limb or it feels like the limb is contorted.

One interesting therapy for phantom limb problems is mirror therapy.

https://www.amputee-coalition.org/resources/mirror-therapy/

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