Although numerous studies provide general support for the importance of genetic factors in the risk for alcohol use disorders (AUDs), candidate gene and genome-wide studies have yet to identify a set of genetic variations that explain a significant portion of the variance in AUDs. One reason is that alcohol-related phenotypes used in genetic studies are typically based on highly heterogeneous diagnostic categories. Therefore, identifying neurobiological phenotypes related to neuroadaptations that drive the development of AUDs is critical for the future success of genetic and epigenetic studies. One such neurobiological phenotype is the degree to which exposure to alcohol taste cues recruits the basal ganglia, prefrontal cortex, and motor areas, all of which have been shown to have a critical role in addictive behaviors in animal studies. To that end, this study was designed to examine whether cue-elicited responses of these structures are associated with AUD severity in a large sample (n=326) using voxelwise and functional connectivity measures. Results suggested that alcohol cues significantly activated dorsal striatum, insula/orbitofrontal cortex, anterior cingulate cortex, and ventral tegmental area. AUD severity was moderately correlated with regions involved in incentive salience such as the nucleus accumbens and amygdala, and stronger relationships with precuneus, insula, and dorsal striatum. The findings indicate that AUDs are related to neuroadaptations in these regions and that these measures may represent important neurobiological phenotypes for subsequent genetic studies.

Recent research has suggested that marijuana use is associated with volumetric and shape differences in subcortical structures, including the nucleus accumbens and amygdala, in a dose-dependent fashion. Replication of such results in well controlled studies is essential to clarify the effects of marijuana. To that end, this retrospective study examined brain morphology in a sample of adult daily marijuana users (n ϭ 29) versus nonusers (n ϭ 29) and a sample of adolescent daily users (n ϭ 50) versus nonusers (n ϭ 50). Groups were matched on a critical confounding variable, alcohol use, to a far greater degree than in previously published studies. We acquired high-resolution MRI scans, and investigated group differences in gray matter using voxel-based morphometry, surface-based morphometry, and shape analysis in structures suggested to be associated with marijuana use, as follows: the nucleus accumbens, amygdala, hippocampus, and cerebellum. No statistically significant differences were found between daily users and nonusers on volume or shape in the regions of interest. Effect sizes suggest that the failure to find differences was not due to a lack of statistical power, but rather was due to the lack of even a modest effect. In sum, the results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and standard volumetric or shape measurements of subcortical structures.

Background Altered functional connectivity in critical networks has been associated with chronic alcohol abuse. In turn, changes in connectivity in executive control networks may undermine the ability to control alcohol consumption. It was hypothesized that network connectivity would be reduced in individuals with problematic alcohol use (ALC) compared to controls and that diminished network connectivity would be associated with greater failure to control drinking. Methods Resting state functional magnetic resonance imaging was analyzed to identify fourteen previously identified intrinsic connectivity networks (ICNs) using a priori regions of interest in cases ranging from binge drinkers to those with severe alcohol use disorder, as well as control subjects. Analyses tested for differences in network connectivity strength between 255 ALC cases and 87 age- and gender-matched controls. Further, structural equation analysis, using 383 ALC cases, tested whether functional connectivity strength mediated the relationship between years of regular drinking and alcohol problems. Results The age- and gender-matched analysis showed that ALC had significantly lower network connectivity strength than controls in the left executive control (LECN), basal ganglia (BG) and primary visual (PV) networks. For all ALC, LECN connectivity strength in negatively correlated with failed control and alcohol disorder severity. Edges connecting parietal regions with dorsolateral prefrontal, middle frontal and temporal regions within the LECN drove these relationships. A positive association between years of drinking and severity of alcohol problems was mediated by reduced executive control network connectivity. Conclusions This study reports relationships between network strength and problematic alcohol use, suggesting that chronic drinking negatively impacts brain connectivity, specifically in the left executive control network. Altered functional connectivity, related to chronic alcohol abuse, may contribute to the etiology of alcohol dependence and relapse.

Altered functional connectivity has been associated with acute and chronic nicotine use. Connectivity alterations, specifically in the right and left executive control networks (RECN/LECN) and the default mode network (DMN), may contribute to the addiction cycle. The objective of this study was to determine if ECN and DMN connectivity is different between non-smokers and smokers and whether reductions in connectivity are related to chronic cigarette use. The RECN, LECN and DMN were identified in resting state functional magnetic resonance imaging data in 650 subjects. Analyses tested for group differences in network connectivity strength, controlling for age and alcohol use. There was a significant group effect on LECN and DMN connectivity strength with smokers (n=452) having lower network strengths than non-smokers (n=198). Smokers had lower connectivity than non-smokers associated with key network hubs: the dorsolateral prefrontal cortex (DLPFC) and parietal (PAR) nodes within ECNs. Further, ECN connectivity strength was negatively associated with pack years of cigarette use. Our data suggest that chronic nicotine use negatively impacts functional connectivity within control networks that may contribute to the difficulty smokers have in quitting.

Background Current work in motivational interviewing (MI) has supported the role of in-session client and therapist language in predicting post-intervention substance use outcomes. In particular, a relationship has been found between specific therapist language (e.g., MI-consistent behaviors), specific types of client speech (e.g., change talk; CT and counter-change talk; CCT), and subsequent drinking outcomes. One hypothesis to explain this phenomenon is that CT is an indication of a neurocognitive shift that happens during the course of the psychosocial intervention. And, it is possible that this shift is responsible for catalyzing and maintaining changes in drinking behaviors following MI interventions. To investigate this question, the effect of CT on blood oxygen level dependent (BOLD) response during the presentation of alcohol cues using fMRI was evaluated. Methods To examine changes in neural response to alcohol cues following client language, 10 adults with alcohol dependence (50% male; 40% Caucasian; 40% Hispanic; M age = 42.6; M years of education = 13.3) were presented with CT and CCT derived from their pre-scan MI session during the presentation of alcohol cues. Results Following CCT, there was significant neural response to alcohol cues in several key reward areas (cluster-corrected p<.05, z > 2.3; orbitofrontal cortex, nucleus accumbens, anterior insula, posterior insula, caudate, putamen). On the contrary, there were no areas of significant activation during exposure to alcohol cues following CT. Conclusions These results indicate that CT may be effectively inhibiting activation in brain regions that respond to the salience of alcohol cues. These findings provide preliminary biological support of the psychosocial literature findings, highlighting the critical importance of change talk during psychosocial interventions.