Increased network centrality of the anterior insula in early abstinence from alcohol

[EN] Abnormal resting-state functional connectivity, as measured by functional magnetic resonance imaging (MRI), has been reported in alcohol use disorders (AUD), but findings are so far inconsistent. Here, we exploited recent developments in graph-theoretical analyses, enabling improved resolution and fine-grained representation of brain networks, to investigate functional connectivity in 35 recently detoxified alcohol dependent patients versus 34 healthy controls. Specifically, we focused on the modular organization, that is, the presence of tightly connected substructures within a network, and on the identification of brain regions responsible for network integration using an unbiased approach based on a large-scale network composed of more than 600 a priori defined nodes. We found significant reductions in global connectivity and region-specific disruption in the network topology in patients compared with controls. Specifically, the basal brain and the insular-supramarginal cortices, which form tightly coupled modules in healthy subjects, were fragmented in patients. Further, patients showed a strong increase in the centrality of the anterior insula, which exhibited stronger connectivity to distal cortical regions and weaker connectivity to the posterior insula. Anterior insula centrality, a measure of the integrative role of a region, was significantly associated with increased risk of relapse. Exploratory analysis suggests partial recovery of modular structure and insular connectivity in patients after 2 weeks. These findings support the hypothesis that, at least during the early stages of abstinence, the anterior insula may drive exaggerated integration of interoceptive states in AUD patients with possible consequences for decision making and emotional states and that functional connectivity is dynamically changing during treatment.The authors wish to thank Prof. Edward Bullmore and Prof. Nicholas Crossley for providing the brain parcellation template and Prof. Markus Heilig for interesting discussions. This work was supported by the European Union's Horizon 2020 research and innovation programme (668863-SyBil-AA), the ERA-Net NEURON programme (FKZ 01EW1112-TRANSALC) and Deutsche Forschungsgemeinschaft (center grants SFB636 and TRR 265 subproject B0867). SC acknowledges the Spanish State Research Agency through the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2017-0723) and the Ministerio de Economía y Competitividad (MINECO) and FEDER funds under grants BFU2015-64380-C2-1-R and BFU2015-64380-C2-2-R. Open Access funding enabled and organized by Projekt DEAL.Bordier, C.; Weil, G.; Bach, P.; Scuppa, G.; Nicolini, C.; Forcellini, G.; Pérez-Ramírez, MÚ.... (2022). Increased network centrality of the anterior insula in early abstinence from alcohol. Addiction Biology. 27(1):1-12. https://doi.org/10.1111/adb.1309611227

Oxytocin attenuates neural response to emotional faces in social drinkers: an fMRI study

Introduction: Oxytocin is a key mediator of emotional and social behavior that seems to be of relevance for the development and maintenance of addictive behaviors. We thus investigated the effect of oxytocin on neural response and behavior during a face-matching task in a sample of social drinkers. Methods: Thirteen social drinkers underwent a randomized double-blind placebo-controlled cross-over functional magnetic resonance imaging face-matching task with and without prior intranasal application of 24 international units oxytocin. Effects of oxytocin and task condition (faces, shapes) on brain activation and individual task performance were assessed. Results: Face-matching compared to shape-matching trials resulted in higher brain activation in the bilateral amygdala, hippocampus and parts of the occipital gyri. Oxytocin application vs. placebo reduced activation in bilateral amygdala, parts of the frontal gyri, and the parietal lobe. Region of interest analyses indicated that the oxytocin-induced attenuation of amygdala response was specific to face-stimuli and associated with lower subjective alcohol craving, and a lower percentage of heavy-drinking days (defined as >= 5 standard drinks/day). Conclusion: For the first time, we could show that a larger oxytocin-induced attenuation of amygdala response to fearful faces is associated with lower subjective craving for alcohol and percentage of heavy drinking days in social drinkers. Modulation of amygdala activation, induced by emotional stimuli, might represent a neurobiological substrate of oxytocin's protective effects on drug seeking behavior

The Effects of Pharmacological Opioid Blockade on Neural Measures of Drug Cue-Reactivity in Humans

Interactions between dopaminergic and opioidergic systems have been implicated in the reinforcing properties of drugs of abuse. The present study investigated the effects of opioid blockade, via naltrexone, on functional magnetic resonance imaging (fMRI) measures during methamphetamine cue-reactivity to elucidate the role of endogenous opioids in the neural systems underlying drug craving. To investigate this question, non-treatment seeking individuals with methamphetamine use disorder (N=23; 74% male, mean age=34.70 (SD=8.95)) were recruited for a randomized, placebo controlled, within-subject design and underwent a visual methamphetamine cue-reactivity task during two blood-oxygen-level dependent (BOLD) fMRI sessions following 3 days of naltrexone (50 mg) and matched time for placebo. fMRI analyses tested naltrexone-induced differences in BOLD activation and functional connectivity during cue processing. The results showed that naltrexone administration reduced cue-reactivity in sensorimotor regions and related to altered functional connectivity of dorsal striatum, ventral tegmental area, and precuneus with frontal, visual, sensory, and motor-related regions. Naltrexone also weakened the associations between subjective craving and precuneus functional connectivity with sensorimotor regions and strengthened the associations between subjective craving and dorsal striatum and precuneus connectivity with frontal regions. In conclusion, this study provides the first evidence that opioidergic blockade alters neural responses to drug cues in humans with methamphetamine addiction and suggests that naltrexone may be reducing drug cue salience by decreasing the involvement of sensorimotor regions and by engaging greater frontal regulation over salience attribution