Increased Orbitofrontal Brain Activation after Administration of a Selective Adenosine A2A Antagonist in Cocaine Dependent Subjects

Background: Positron Emission Tomography imaging studies provide evidence of reduced dopamine function in cocaine dependent subjects in the striatum, which is correlated with prefrontal cortical glucose metabolism, particularly in the orbitofrontal cortex. However, whether enhancement of dopamine in the striatum in cocaine dependent subjects would be associated with changes in prefrontal cortical brain activation is unknown. One novel class of medications that enhance dopamine function via heteromer formation with dopamine receptors in the striatum is the selective adenosine A2A receptor antagonists. This study sought to determine the effects administration of the selective adenosine A2A receptor antagonist SYN115 on brain function in cocaine dependent subjects. Methodology/Principle Findings: Twelve cocaine dependent subjects underwent two fMRI scans (one after a dose of placebo and one after a dose of 100 mg of SYN115) while performing a working memory task with three levels of difficulty (3, 5, and 7 digits). fMRI results showed that for 7-digit working memory activation there was significantly greater activation from SYN115 compared to placebo in portions of left (L) lateral orbitofrontal cortex, L insula, and L superior and middle temporal pole. Conclusion/Significance: These findings are consistent with enhanced dopamine function in the striatum in cocaine dependent subjects via blockade of adenosine A2A receptors producing increased brain activation in the orbitofrontal cortex and other cortical regions. This suggests that at least some of the changes in brain activation in prefrontal cortical regions in cocaine dependent subjects may be related to altered striatal dopamine function, and that enhancement of dopamine function via adenosine A2A receptor blockade could be explored further for amelioration of neurobehavioral deficits associated with chronic cocaine use

Long-Acting Injectable Naltrexone for the Management of Patients with Opioid Dependence

Opioid dependence is a condition with serious clinical ramifications. Treatment has focused on detoxification, agonist therapy with methadone or buprenorphine, or remission maintenance with the opioid antagonist, naltrexone. Treatment with oral naltrexone has been limited by poor treatment adherence and relapse. Studies with long-acting formulations have shown increased treatment adherence. Extended-release injectable naltrexone has been used for the treatment of alcohol dependence, and has recently received an indication for treatment of opioid dependence from the US Food and Drug Administration. Dosing occurs once monthly and existing data with long-acting naltrexone supports efficacy of treatment for opioid dependence; however published data is sparse. Treatment with long-acting naltrexone should be monitored for hepatotoxicity, and patients should be made aware of increased risk of overdose with administration of opioids during and immediately after discontinuation of long-acting naltrexone

Data from 617 Healthy Participants Performing the Iowa Gambling Task: A “Many Labs” Collaboration

This data pool (N = 617) comes from 10 independent studies assessing performance of healthy participants (i.e., no known neurological impairments) on the Iowa gambling task (IGT)—a task measuring decision making under uncertainty in an experimental context. Participants completed a computerized version of the IGT consisting of 95 – 150 trials. The data consist of the choices of each participant on each trial, and the resulting rewards and losses. The data are stored as .rdata, .csv, and .txt files, and can be reused to (1) analyze IGT performance of healthy participants; (2) create a “super control group”; or (3) facilitate model-comparison efforts

Correction: Data from 617 Healthy Participants Performing the Iowa Gambling Task: A “Many Labs” Collaboration

This article details a correction to the article: Steingroever, H. et al., (2015). Data from 617 Healthy Participants Performing the Iowa Gambling Task: A “Many Labs” Collaboration. Journal of Open Psychology Data. 3:e5. DOI: <a href="http://doi.org/10.5334/jopd.ak" target="_blank">http://doi.org/10.5334/jopd.ak</a