Why cocaine users just can't learn their lesson: it alters their brain
Chronic cocaine use alters brain circuits that help us learn from mistakes, a new study suggests.

Chronic cocaine use alters brain circuits that help us learn from mistakes, a new study suggests.
The study, in the Journal of Neuroscience, offers an explanation for the cycle of destructive decisions that addicts exhibit.
Researchers measured EEG signals from a part of the midbrain that has been associated with how the brain manages errors in reward prediction. Neurons there release and absorb more dopamine when things go better or worse than expected, and less when events meet expectations.
That feedback helps explain why we're so pleasantly surprised at unexpected rewards, so disappointed at unforeseen penalties, and relatively blase about "predictable" outcomes.
"The brain learns from it - whether you should go ahead with this experience the next time or you should stay away from it," said the study's lead researcher, Muhammad Parvaz, a cognitive neuroscientist at the Icahn School of Medicine at Mount Sinai in New York.
Among chronic users, said Parvaz, "the worse-than-expected response was not there".