dopamine and neuroeconomics

Anyone ever see the movie Dopamine? The movie implies that dopamine mediates love and other warm, fuzzy feelings. How did anyone come to the conclusion that dopamine has anything to do with love? Becuase small, furry critters (prairie and montane voles) showed different amounts of dopamine activity (really, dopamine receptors). In the wild, prairie voles form pair bonds. Often, one night of mating can lead to a lifetime together. Montane voles on the other hand, are promiscuous and never call when they say they will. Bastards. But if you tweak dopamine in the right brain area in the right way in montane voles, voila!, they become pair-bonded. Thus, tweaking dopamine can be construed as giving a vole a love potion (as illustrated in Nature).
Too bad, though that pair-bonded voles aren't really monogamous. Sexually, they're promiscuous, but then raise any pups in their pair-bonds. So really, dopamine mediates Catholic guilt.... (mostly kidding).

What brought on this rant on dopamine? Well, this morning, AT posted how dopamine is a "chemical in the brain that triggers sensations of pleasure when you buy something new." That's about as correct as dopamine mediating love. True, for a couple of decades, most scientists believed that dopamine=pleasure. But this isn't really the case anymore. It's so not the case that the guy who originally posited that dopamine=pleasure doesn't believe it. Easiest, lay person's example of dopamine NOT mediating pleasure is a Parkinson's patient. Clinical symptoms of Parkinson's don't develop until about 80% of the cells making dopamine are dead. Yet people afflicted with Parkinson's do not have any problem experiencing pleasure.

So if not love or pleasure, what does dopamine do? That's the million-dollar question. Actually, it's probably the trillion dollar question, considering how all drugs of abuse as well as a crapload of prescription medication (Ritalin, anyone?) affect the dopamine system. And the answer, is, of course, 42.

In other words, lots of scientists have lots of ideas and are doing lots of experiments to figure out what dopamine is doing in the brain. And no one doubts that it's doing a LOT of different things. Primary symptoms of Parkinson's include the inability to begin or control movement and the slowing of movement. There are other symptoms, though, that are less visually obvious: cognitive impairments, memory issues, sleep issues, mood disorders. And when patients take L-DOPA (which is one of the more well known Parkinson's medication), some become pathological gamblers.... These patients take risks with their money similarly to how hard-core drug abusers risk their lives for a high.

So dopamine might also have a role in decision-making (which was implied in the previously mentioned AT post). Should I buy that? Is it worth it? Will the wrath of my significant other be too much to bear? What does the dopamine spiking in my brain have to do with how I'm going to decide? And how is this decision-making process altered by drugs (both prescription and illegal) or disease? Do we really know anything concrete about what dopamine's doing in the brain?

Hopefully, I'll know more in the next couple of years.