I think the best part about this weird Friday is that I don't have to write it! A good thing too, I have a life outside the blog (crazy, I know), and that life has been nothing short of insane. Today's is courtesy of my friend Claire, who found it over at Mind Hacks.
Portenoy, et al. "Compulsive thalamic self-stimulation: a case with metabolic, electrophysiologic, and behavioral correlates" Pain, V 27, 1986.
Well, ok, maybe I'll talk about it a LITTLE...
...but it will have to be very fast.
Ok, so first off, this patient would NOT be the first person I would think of putting a deep implant electrode into, she's not exactly a stellar candidate. First of all, she's an alcoholic. She had chronic pain as well, and had surgery at least five times trying to cure it, as well as behavioral therapy, acupuncture, and a LOT of opioids. The surgery always failed to work, and the opioids proved to be too much fun, and they had to take her off them because she kept upping her own dose. So let's start out knowing we have a pretty addictive personality, here.
So they started using thalamic stimulation. This sounds really frightening, but it's a lot more common than you'd think. Right now thalamic stimulation is mostly used for people with very advanced Parkinson's disease (for more on that, check out the post I wrote for the most recent Giant's Shoulders). It's not a very easy surgery to do at all. The thalamus is in the very middle of your brain, shaped pretty much like an egg, and contains tons of different nuclei doing lots of different things. Pretty much everything you do (sensory and motor) has to pass through the thalamus (with the odd exception of your sense of smell). The thalamus modulates all of these signals coming from all over the brain, and puts it together to send signals out to areas such as the primary motor cortex, which then can start a movement signal, or to sensory areas such as the optic and auditory areas to modulate information. So it's REALLY important. And sticking an electrode in it can be some risky business.
But they did, in an area (the nVPL), in a hope to decrease the chronic pain. Basically, they put a little electrode in there, and give you a little box. You press the button on the box when you feel pain (or tremor, in the case of Parkinson's), and it stimulates, and you're ok.
It didn't appear to work for the pain, but all of a sudden, the woman started to experience...feelings. When she stimulated the area, she experienced pretty intense erotic sensations, though apparently not ones that ever resulted in orgasm. This woman seemed to like addictive things a lot, and so when she figured out it felt good, it felt REALLY good. She stopped seeing her family, completely neglected personal hygiene, and even developed a sore on the finger used to stimulate! She also kept adjusting the amplitude, ramping it up higher and higher to feel better and better. She would sometimes try to give the stimulator back to the doctors, swearing she was off it, and then beg for it's return a few days later. Classic addiction to something that isn't really quite sex.
The authors noted that it was the first time that addiction to brain stimulation had been noted in humans, and they were probably right, but that's mostly for lack of trying in humans. Self stimulation in animals has been very common in studies of reward and addiction for a good while now. It's well known that if you give a rat a stimulator in the right place, it'll hit the lever forever. So while it's still useful for basic scientific research, I don't know that I'd want one. Though if you're going to have a side effect from brain surgery...
Portenoy RK, Jarden JO, Sidtis JJ, Lipton RB, Foley KM, Rottenberg DA. (1986). Compulsive thalamic self-stimulation: a case with metabolic, electrophysiologic, and behavioral correlates Pain, 27