The role of social stimuli content in neuroimaging studies investigating alcohol cue-reactivity

Peer-elicited alcohol craving in adolescents and emerging adults: Bridging the laboratory and natural environment

BACKGROUND

Although peers figure prominently in developmental models of alcohol use, our understanding of the influence of peer social context in cue reactivity paradigms with adolescents and emerging adults in the human laboratory and the natural environment is limited. This study tested associations between alcohol craving among youth in the human laboratory using alcohol-related images, with and without peers, and in the natural environment using ecological momentary assessment (EMA).

METHODS

Data for this preregistered secondary analysis were collected prior to randomization in two medication trials (N = 115). Participants completed an image cue exposure paradigm at the baseline laboratory session followed by approximately 7 days of EMA.

RESULTS

In the laboratory, model-based mean comparisons from multilevel models (MLMs) showed that all drinking images elicited greater craving than neutral images. No differences were observed across the three image categories containing alcohol. Image category by age interactions demonstrated that, compared to older youth, younger youth displayed lower craving in response to neutral versus social drinking context with peers images and older, compared to younger, youth displayed higher craving in response to nonsocial drinking images versus social drinking contexts with peers images. In the natural environment, craving was greatest when youth were in the presence of alcohol-using peers and alcohol-related cues, regardless of age. Laboratory craving to alcohol images was positively associated with craving in the natural environment.

CONCLUSIONS

For youth, peers are a salient social context associated with increased craving, particularly in the natural environment. Laboratory cue reactivity to alcohol images predicted real-world craving, further supporting the ecological validity of this paradigm in youth.

A Pilot Study on Approach Bias Modification in Smoking Cessation: Activating Personalized Alternative Activities for Smoking in the Context of Increased Craving

Background

The act of smoking has been associated with the automatic activation of approach biases towards smoking-related stimuli. However, previous research has produced mixed findings when smokers are trained to avoid such smoking-related stimuli through the application of Approach Bias Modification (ApBM). As such, this study aimed to test an improved ApBM (ApBM +), where smokers were trained to approach personalized alternative activities for smoking in the context of increased craving, in addition to training smoking-avoidance responses.

Methods

Sixty-seven daily smokers motivated to quit (M age = 29.27, 58.2% female) were randomly assigned to seven sessions of either ApBM + (n = 26), standard-ApBM (n = 19), or sham-ApBM (n = 22), after a brief motivational smoking intervention. Primary outcomes of approach biases for smoking and for alternative activities and secondary outcomes of smoking-related behaviors were assessed at pre-test, post-test, and 1-month follow-up.

Results

Overall, no group differences by condition were demonstrated in changing approach biases or smoking-related behaviors at post-test and 1-month follow-up. A trend level indication for differences in changes of smoking-approach biases between sham-ApBM and ApBM + for relatively heavy smokers was found at post-test. This was primarily driven by a significant increase in smoking-approach biases within the sham-ApBM condition and a trend decrease in smoking-approach biases within the ApBM + condition.

Conclusions

Our findings did not provide support for the current ApBM + concerning improved effects across the whole sample. Diverging training effects on approach biases for smoking in relatively heavy smokers warrants further research, for which we provide some suggestions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12529-021-10033-x.

Neurobiological correlates of cue-reactivity in alcohol-use disorders: A voxel-wise meta-analysis of fMRI studies

Altered brain responses to alcohol-associated stimuli are a neural hallmark of alcohol-use disorder (AUD) and a promising target for pharmacotherapy. However, findings in cue-reactivity based functional MRI (fMRI) studies are inconclusive. To investigate the neural substrates of cue-reactivity and their relevance to treatment outcomes, alcohol craving and relapse in AUD patients, we performed five meta-analyses using signed differential mapping software. Our meta-analysis revealed that alcohol cues evoke greater cue-reactivity than neutral cues in the mesocorticolimbic circuit and lower reactivity in the parietal and temporal regions in AUD patients. Compared to controls, AUD individuals displayed hyperactivations in the medial prefrontal cortex and anterior/middle part of the cingulate cortex. After receiving AUD treatment, AUD patients exhibited greater activations in the precentral gyrus but reduced activations in the bilateral caudate nucleus, insula, right DLPFC, and left superior frontal gyrus. No significant results were found in cue-reactivity correlates of alcohol craving and relapse. Our results implicate cue-induced abnormalities in corticostriatal-limbic circuits may underline the pathophysiology of AUD, and have translational value for treatment development.

Alcohol Causes Lasting Differential Transcription in Drosophila Mushroom Body Neurons

Repeated alcohol experiences can produce long-lasting memories for sensory cues associated with intoxication. These memories can problematically trigger relapse in individuals recovering from alcohol use disorder (AUD). The molecular mechanisms by which ethanol changes memories to become long-lasting and inflexible remain unclear. New methods to analyze gene expression within precise neuronal cell types can provide further insight toward AUD prevention and treatment. Here, we used genetic tools in Drosophila melanogaster to investigate the lasting consequences of ethanol on transcription in memory-encoding neurons. Drosophila rely on mushroom body (MB) neurons to make associative memories, including memories of ethanol-associated sensory cues. Differential expression analyses revealed that distinct transcripts, but not genes, in the MB were associated with experiencing ethanol alone compared to forming a memory of an odor cue associated with ethanol. Adult MB-specific knockdown of spliceosome-associated proteins demonstrated the necessity of RNA-processing in ethanol memory formation. These findings highlight the dynamic, context-specific regulation of transcription in cue-encoding neurons, and the lasting effect of ethanol on transcript usage during memory formation.

Neural response to betel quid cues in chewers: a functional magnetic resonance imaging study

The World Health Organization regards betel quid (BQ) as a human carcinogen. The current study analyzes whether the BQ cues can elicit activity in the chewers' craving-related brain areas. We adopted a cue-reactivity paradigm to examine the changes in the brain activities. The urge intensity was also included to examine whether it can moderate the brain areas stimulated by BQ cues. Sixteen male BQ chewers and 16 healthy male controls were recruited and analyzed. Four types of cues were adopted: BQ cues, matched food cues, visual control cues, and resting crosshair cued. The most direct and important comparison was between the brain activities elicited by the BQ cues versus those by the food cues. Furthermore, to test the current urge intensity effect, we compared BQ chewers with a strong urge versus those with a weak urge. All of the three-dimension anatomical and multi-slice task-based functional images were acquired using 3 T MRI. We found that (1) the BQ chewers and the healthy controls had similar brain activation patterns when comparing any two cue types, (2) the high-urge (not the low-urge) chewers showed craving-related activations (e.g., anterior cingulate cortex, medial orbitofrontal gyrus, and superior frontal gyrus) in the critical BQ cues vs. the food cue comparisons. (3) The high-urge chewers had larger contrast activations (BQ - Food) in many craving-related brain areas than low-urge chewers did (e.g., frontal gyrus). The urge states endorsed by the chewers can moderate the neural responses to BQ cues. Multisensory cues should be considered to elicit more intense and consistent cravings.

Alcohol usage predicts holistic perception: A novel method for exploring addiction

Holistic perception is a special form of automatic and experience dependent processing that prioritises objects of interest through the visual system. We therefore speculated that higher levels of alcohol consumption may be associated with enhanced holistic perception for alcohol cues. In our first experiment, we confirmed this hypothesis by showing that increasing regular alcohol usage was associated with greater holistic perception of alcohol, but not non-alcohol, cues. We replicated this finding in a second experiment, but confirmed drink-specific holistic perception for lager cues was not predicted by experience with that drink, but general alcohol usage. In our final experiment when alcohol images were absent from the task, higher levels of alcohol consumption predicted decreased holistic perception for non-rewarding cues. Alcohol use is therefore linked to inverse alterations in holistic perception for alcohol versus non-alcohol cues, with the latter's effects context dependent. We hypothesise that such inverse relationships may be due to limited cortical resources becoming reutilised for alcohol cues at the expense of other stimuli. Future work will be required to determine holistic perception's role in maintaining addiction, its predictive value in successful abstinence, and its relationship with characteristics of addiction such as cue reactivity, attentional biases and personality traits.

Brain Functional Magnetic Resonance Imaging Cue-reactivity Can Predict Baclofen Response in Alcohol Use Disorders

Objective

Baclofen is a promising treatment for alcohol use disorders (AUD), although its clinical response in humans is mixed. The present study aimed at investigating the impact of baclofen treatment on cue-induced brain activation pattern and its relationship with relapse outcomes.

Methods

Twenty-three inpatients with AUD underwent a functional magnetic resonance imaging cue-reactivity task before beginning medication with baclofen and 2 weeks later. Twelve additional inpatients with AUD, who did not receive any anticraving medications, formed the control group. All subjects were prospectively followed up for 90 days post-discharge or until lapse to first alcohol use.

Results

Whole-brain linear mixed effects analysis revealed a significant group-by-time interaction with greater activation of the bilateral dorsolateral pre-frontal cortex and right anterior cingulate cortex (ACC) following baclofen treatment in comparison with the control group. Further, cox regression analysis revealed that increased activation of ACC and deactivation of insular cortex (IC) was associated with longer time to first alcohol use only in the baclofen treatment group but not in the control group.

Conclusion

This study provides preliminary evidence for the neural predictors of baclofen treatment response in AUD. Baclofen treatment in AUD was associated with changes in cue-reactivity at critical brain regions within the incentive-salience network. Importantly, baclofen treatment-related specific activation of regions involved in cognitive control (ACC) and deactivation of regions involved in reward anticipation (IC) prolonged the time to first alcohol drink.

Non-Alcoholic Beverage Cues as Specific Comparison Images to Alcohol Image Cues

BACKGROUND

Visual alcohol cues are often used to elicit craving (e.g., cue-reactivity), and selection of appropriate comparison cues is important to isolate the specific effect of craving for alcohol.

OBJECTIVES

In the current study, via the development of a new set of non-alcoholic beverage cues, we examine measurement and methodological choices in testing alcohol images for cue-reactivity studies.

METHODS

The current project combined two independent studies of hazardous (Study 1; n = 80) and recent drinkers (Study 2; n = 244) recruited from Amazon Mechanical Turk. Participants viewed either alcohol cues (Lovett, Ham, & Veilleux, 2015 ) or newly developed non-alcoholic beverage cues. We also randomly assigned people to rate the cues regarding motivational (e.g., affect, craving for alcohol, resistance to alcohol) responses or non-motivational features (e.g., artistry).

RESULTS

In Study 1, we included presentation of non-beverage objects, and found that beverages were rated as more positive, less negative and with higher craving than non-beverage objects. In the combined sample, we found that the alcohol beverage cues were associated with greater craving than non-alcoholic beverage cues, and that there were no differences between cue types on either positive or negative affect. We also found an interaction between drinking experience and cue type in predicting resistance to drinking.

CONCLUSIONS

We conclude that the choice of control cues in alcohol cue-reactivity studies is important, and that the currently developed non-alcoholic beverage cue set provides an adequate control for alcohol beverage cues for use in cue-reactivity paradigms.