'Back Door' in the Brain May be Linked to Cocaine Addiction
Scientists may have discovered an unknown "back door" into the brain linked to cocaine addiction. The findings may explain why individuals addicted to the substance may have trouble dropping the habit.
Cocaine is a stimulant drug that can lead to addiction when taken repeatedly. Quitting the habit can be extremely difficult for some. In fact, around four in ten individuals who relapse report having experienced a craving for the drug. This means that six out of ten people have relapsed for reasons other than "needing" the drug.
"Most people who use cocaine do so initially in search of a hedonic 'high,'" said David Belin, one of the researchers, in a news release. "In some individuals, though, frequent use leads to addiction, where use of the drug is no longer voluntary, but ultimately becomes a compulsion. We wanted to understand why this should be the case."
Previous research has shown that when rat were allowed to self-administer cocaine, dopamine-related activity occurred first in the nucleus accumbens, a region of the brain that plays a role in goal-directed behavior. Over an extended period, though, this activity transferred to the dorsolateral striatum, which plays a role in habitual behavior.
In this latest study, the researchers studied the brains of rats addicted to cocaine through self-administration of the drug. They found a previously unknown pathway within the brain that links impulse with habits.
The pathway actually links the basolateral amygdala indirectly with the dorsolateral striatum. This circumvents the prefrontal cortex and means that an addicted individual would not be necessarily aware of their desire to take the drug.
"We've always assumed that addiction occurs through a failure of our self-control, but now we know this is not necessarily the case," said Belin. "We've found a back door directly to habitual behavior."
The findings are published in the journal Nature Communications.
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