Brain Imaging of Human Drug Abuse

National Institute On Drug Abuse

Investigators

Linked publications, trials & patents

Abstract

1. Functional connectivity of dorsolateral prefrontal cortex predicts cocaine relapse: implications for neuromodulation treatment: Implications for neuromodulation treatment. Relapse is one of the most perplexing problems of addiction. The dorsolateral prefrontal cortex dlPFC is crucially involved in numerous cognitive and affective processes that are implicated in the phenotypes of SUDs. The dlPFC is an anatomically large and functionally heterogeneous region, and the specific dlPFC locus and dlPFC-based functional circuits that contribute to drug relapse and/or treatment outcome remain unknown. We investigated the relationship of cocaine relapse with functional circuits from 98 dlPFC ROIs in a cohort of cocaine dependent patients following a treatment intervention. Functional connectivity from only 3 of the 98 dorsolateral prefrontal cortex loci, significantly predicted cocaine relapse with an accuracy of 83.9%, 84.6% and 85.4%. Protective and risk circuits related to these dlPFC loci were identified that have previously been implicated to support 'bottom up' drive to use drug and 'top down' control over behavior together with social emotional, learning and memory processing. The identified dlPFC loci may serve as potential neuromodulation targets to be tested in subsequent clinical studies for addiction treatment and as clinically relevant biomarkers of its efficacy. 2. Common and Gender-Specific Associations with Cocaine Use on Gray Matter Volume: Data from the ENIGMA Addiction Working Group. Gray Matter Volume (GMV) in frontal cortical and limbic regions is susceptible to cocaine-associated reductions in cocaine-dependent individuals (CD) and is negatively associated with duration of cocaine use. Voxel-based morphometry data derived from the ENIGMA Addiction Consortium were used to investigate potential gender differences in GMV in CD individuals compared to matched controls (CTL). Diagnostic differences were predominantly found in frontal regions (CD < CTL). Interestingly, gender diagnosis interactions in the left anterior insula and left lingual gyrus were also documented, driven by differences in women (CDW < CTLW). Further, lower right hippocampal GMV was associated with greater cocaine duration in CDM. Given the importance of the anterior insula to interoception and the hippocampus to learning contextual associations, results may point to gender-specific mechanisms in cocaine addiction. 3. Predicting alcohol dependence from multi-site brain structural measures. To identify neuroimaging biomarkers of alcohol dependence (AD) from structural MRI, it may be useful to develop classification models that are explicitly generalizable to unseen sites and populations. Evolutionary-based feature selection leveraging leave-one-site-out cross-validation, to combat unintentional learning, identified cortical thickness in the left superior frontal gyrus and right lateral orbitofrontal cortex, cortical surface area in the right transverse temporal gyrus, and left putamen volume as final features. Ridge regression restricted to these features yielded a test-set area under the receiver operating characteristic curve of 0.768. These findings identify potential biomarkers for individuals with current AD. 4. Mapping cortical and subcortical asymmetries in substance dependence. Brain asymmetry reflects left-right hemispheric differentiation, which is a quantitative brain phenotype that develops with age and can vary with psychiatric diagnoses. We found that substance dependence was significantly associated with differences in volume asymmetry of the nucleus accumbens (NAcc; less rightward; Cohen's d = 0.15). This effect was driven by differences from controls in individuals with alcohol dependence and nicotine dependence. This suggests that disrupted structural asymmetry in the NAcc may be a characteristic of substance dependence. 5. Repetitive Transcranial Magnetic Stimulation (rTMS) in Addiction. Recent findings report that rTMS has emerged as a potential treatment due to its promising results in terms of craving reduction, and its ability to induce neuroplasticity and modulate brain activity. Future research should identify potential parameters (i.e., duration, number of stimulation treatments, stimulation frequency, intensity, target brain region) of stimulation in rTMS studies for the most effective, safe treatment of drug addiction. Personalization of rTMS treatments, as well as optimization of stimulation protocols, should be the main focus of future research in this area. 6. Reproducibility in the absence of selective reporting: an illustration from large scale brain asymmetry research Poor reproducibility of scientific findings has received much attention over recent years. We revisited hemispheric effects from the perspective of reproducibility. We found an average reproducibility rate of 63.2%. As expected, reproducibility was higher for larger effects and in larger datasets. These findings constitute an empirical illustration of reproducibility in the absence of publication bias or p hacking, when assessing realistic biological effects in heterogeneous neuroscience data, and given typically-used sample sizes.