Addictive drugs change the brain’s reward circuits that may underlie drug craving and relapse after long periods of abstinence. New research has found a specific neural mechanism that may be connected to persistent drug-seeking behavior and could help to guide strategies for the development of new therapies for cocaine addiction.
The ventral tegmental area (VTA) is a region of the brain that is activated when cocaine users have a craving for the drug after being exposed to cocaine-associated cues. The medial prefrontal cortex (Mpfc), which receives input from the VTA via circuits that use dopamine, has been connected to drug craving after cocaine withdrawal. Increases in the level of brain-derived neurotrophic factor (BDNF) have been seen in the VTA and mPFC in rats after withdrawal from repeated cocaine exposure.
“BDNF plays a key role in modulating the structure and function of synapses, the sites of communication between neurons. Therefore, increased BDNF after cocaine withdrawal may drive synaptic changes that contribute to compulsive drug seeking behavior,” said Dr. Mu-ming Poo, lead researcher at the University of California at Berkeley. “It has been shown that increased BDNF in the VTA after cocaine withdrawal in rats promotes the drug-dependent motivational state.”