Question

The neurotransmitter _______ has been a primary focus of drug abuse research because of its well-known effect on a part of the brain's reward system known as the nucleus accumbens. Drugs that increase the activity of this neurotransmitter are most likely to result in physical dependence.

Answer 1

The correct answer is:  "dopamine" .
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            "The neurotransmitter    dopamine  has been a primary focus of drug abuse research because of its well-known effect on a part of the brain's reward system known as the nucleus accumbens.  Drugs that increase the activity of this neurotransmitter are most likely to result in physical dependence."
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