Cocaine can quickly rewire high-level brain circuits that support learning, memory and decision-making, say scientists who believe the findings shed new light on the frontal brain's role in drug-seeking behavior and may be key to tackling addiction.
The researchers, from the University of California, Berkeley, and University of California, San Francisco, say the key areas of the brain affected are the frontal lobes. Using laser scanning microscopy, the researchers made images of nerve cell connections in the frontal cortices of live mice before and after the mice received their first dose of cocaine and, within just two hours, observed the formation of new dendritic spines. After just one dose of cocaine, mice showed fast and robust growth of dendritic spines, which are tiny, twig-like structures that connect neurons and form the nodes of the brain's circuit wiring.
"Our images provide clear evidence that cocaine induces rapid gains in new spines, and the more spines the mice gain, the more they show they learned about the drug," said Linda Wilbrecht, lead author of the study.
For mice, "learning about the drug" can mean seeking it out to the exclusion of meeting other needs, which may explain how addiction in humans can override other considerations that are necessary for a balanced life: "The downside is, you might be learning too well about drugs at the expense of other things," Wilbrecht said.
The drug-induced changes in the brain may explain how drug related cues come to dominate decision-making in a human drug user, leaving more mundane tasks and cues with relatively less power to activate the brain's decision-making centers.
Discuss this article in our forum
High IQ level linked to illegal drug use
Wives Of Drug Takers At Risk
Source: University of California - Berkeley