" Dopamine enhances the ability of neurons to transmit signals between one another. How? By acting as an agonist (as opposed to antagonist), or a substance that enhances neural activity. Dopamine binds to specific receptor molecule sites on the synaptic clefts of the neurons, as if it were the CTS that normally bind there.12 It increases the rate of neural firing in association with pattern recognition, which means that synaptic connections between neurons are likely to increase in response to a perceived pattern, thereby cementing those perceived patterns into long-term memory through the actual physical growth of new neural connections and the reinforcement of old synaptic links.
Increasing dopamine increases pattern detection; scientists have found that dopamine agonists not only enhance learning but in higher doses can also trigger symptoms of psychosis, such as hallucinations, which may be related to that fine line between creativity (discriminate patternicity) and madness (indiscriminate patternicity). The dose is the key. Too much of it and you are likely to be making lots of Type I errors—false positives—in which you find connections that are not really there. Too little and you make Type II errors—false negatives—in which you miss connections that are real. "

― Michael Shermer , The Believing Brain: From Ghosts and Gods to Politics and Conspiracies How We Construct Beliefs and Reinforce Them as Truths