By Tinkering With Neurotransmitter, Scientists 'Remote-Control' Rats

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The neurotransmitter dopamine influences risky decisions like betting. Steve Marcus / Reuters

When you make a risky decision and succeed—winning your bet on the Monday Night Football game, for example—neurons in various parts of your brain release a neurotransmitter called dopamine. But when you lose, the neurons go quiet, and don’t release dopamine.

Sometimes called the “feel-good” chemical, dopamine is also released during sex and eating food. This fine-tuned dopamine system quite delicately helps guide decisions, by rewarding “good” outcomes, and tamping down decisions that lead to something bad.

However, sometimes this system can be hijacked or malfunction—drugs release dopamine and encourage their continued use, for example. And while the high you get from winning a bet feels good, it can encourage continued betting, which can become problematic in some people. Abnormal levels of dopamine, or a dysfunction in the way that the brain processes it, are thought to be involved in disorders from problem gambling to schizophrenia.

But what if you could alter this system to positively change behavior?

Scientists have accomplished this feat of behavioral command in rats, according to a new study, published today (Sep. 11) in the journal Neuron. Researchers at the University of British Columbia set up a system where rats could either press a lever that would reliably give them a small pellet of food, or press another that gave more food, but inconsistently. The former choice was the safe “bet,” the latter the risky one.

The scientists found that by electrically stimulating dopamine-releasing neurons after rats made the risky choice and “lost,” they could make the rats keep making those high-risk bets. It was as if their brains were telling them they had “won,” said study author Stan Floresco, who studies neural circuits at the University of British Columbia.

Likewise, when scientists electrically suppressed dopamine release in rats who made the risky choice and got a treat (i.e., “won” the bet), the animals would quit making this dicey decision.

“We could remote-control them to a certain extent,” Floresco told Newsweek.

Even though the study was done in rats, the findings should be applicable to humans, since “the circuitry that underlies decision-making seems to hold between species,” Floresco said.

It’s been known for some time that dopamine helps guide motivated behavior, said Nathaniel Daw, a researcher at New York University who wasn’t involved in the study. But much of the research in this area has dealt with correlation, as opposed to causation. In this research, though, the tweaks to dopamine appear to directly influence behavior on an instantaneous basis, which hasn’t been clearly shown before in this way, Daw told Newsweek.

“It looks like this paper is about the cleanest demonstration so far [showing] that the experimenters are able to push around animals' preferences about options on a trial-by-trial basis,” Daw said. “This is the kind of thing we hoped and theorized would be possible, but it hadn't really been demonstrated—it really puts all the pieces together in a clean way.”