Cortical Activation during Cocaine Use and Extinction in Rhesus Monkeys

This study deals with elicit cocaine use associated with craving and drug use. This study used functional magnetic resonance imaging to view cocaine-induced changes in brain activity in rhesus monkeys. Previous studies show certain areas that are activated during cocaine use. For example, blood flow increases in the anterior cingulated and amygdala. This study comprised of three phases. The first phase consisted of the acute effects of cocaine administered were characterized in four drug-naïve rhesus monkeys. The second phase was the same four subjects were trained to self-administer cocaine under a simple fixed ratio schedule. The last phase used three subjects with an extensive history of cocaine use were trained to self-administer cocaine under a complex schedule. Finally, the effectiveness of drug-related stimuli to induce changes in cerebral blood flow was characterized during extinction conditions in the same three subjects. The results were obtained by use of an fMRI. In this study, the results showed the same activation in the rhesus monkeys would be found in humans. Activation of the anterior cingulated and the dorsolateral prefrontal cortex has been observed in response to the administration of cocaine. The results show that there are qualitative differences in the patterns of brain activation induced by self administration of the cocaine and scheduled doses of the cocaine. When the drug was self-administered, there was more activation in the brain. The areas of major activation included the anterior cingulated cortex. In conclusion, there was more activation in the brain when the subjects were able to administer the drug themselves. Perhaps this is because there is more pleasure associated with doing things by yourself. When you do things by yourself, there are feelings of accomplishment and higher self-esteem.  

Howell, L.L., Votaw, J.R., Goodman, M.M., & Lindsey, K.P. (2010). Cortical activation during cocaine use and extinction in rhesus monkeys. Psychopharmacology, 208(2), 191-199. doi:10.1007/s00213-009-1720-3

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