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In a study published today in the Journal of Neuroscience, funded mainly by the Wellcome Trust, researchers led by Professor Ray Dolan have shown that increased levels of dopamine – a chemical in the brain involved in mediating reward, motivation, and learning through reinforcement, – make us more likely to opt for instant gratification, rather than waiting for a more beneficial reward.
The answer to the latter question is, yes. Although dopamine may be crucial to making decisions about future pleasure, too much of it might distort those decisions. A surplus of dopamine is at the root of addiction, for instance: Cocaine, for one, works in part by preventing brain cells from reabsorbing dopamine that the brain has released in connection with pleasurable sensations. And once the brain has learned to like cocaine, it causes all kinds of self-destructive behavior to satisfy its cravings.
In the communal imagination, dopamine is about rewards, and feeling good, and wanting to feel good again, and if you don’t watch out, you’ll be hooked, a slave to the pleasure lines cruising through your brain.
The caricature of dopamine as the chemical of hedonism and pleasure - it's what drives us to enjoy sex, drugs and rock and roll - was always mostly misleading. While dopamine does predict the arrival of rewards, the neurotransmitter is much more important that.
To observe neurotransmitter uptake and release from individual presynaptic terminals directly, we designed fluorescent false neurotransmitters as substrates for the synaptic vesicle monoamine transporter.
“Near-miss” events, where unsuccessful outcomes are proximal to the jackpot, increase gambling propensity and may be associated with the addictiveness of gambling, but little is known about the neurocognitive mechanisms that underlie their potency. Using a simplified slot machine task, we measured behavioral and neural responses to gambling outcomes.
because of reward expectancy the dopamine system is most active when we think we can control the outcome and modify our strategy next time, even if that sense of control is completely false. (Mind Hacks)
Researchers are one step closer to understanding the neurobiology that allows people to successfully learn motivated behaviors by associating environmental cues with rewarding outcomes
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Midbrain dopamine neurons fire in two characteristic modes, tonic and phasic, which are thought to modulate distinct aspects of behavior. When an unexpected reward is presented to an individual, midbrain dopamine neurons fire high frequency bursts of electrical activity. Those bursts of activity allow us to learn to associate the reward with cues in our environment, which may predict similar rewards in the future.
"New research is linking dopamine to complex social phenomena and changing neuroscience in the process." (Seed)
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The importance of dopamine was discovered by accident. In 1954 James Olds and Peter Milner
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At first the dopamine neurons didn’t fire until the juice was delivered; they were responding to the actual reward. However, once the animal learned that the tone preceded the arrival of juice — this requires only a few trials — the same neurons began firing at the sound of the tone instead of the sweet reward. And then eventually, if the tone kept on predicting the juice, the cells went silent. They stopped firing altogether.
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