To explore the mechanism of tobacco addiction using structural and functional MRI: a preliminary study of the role of the cerebellum-striatum circuit

The structural and functional brain alternations in tobacco use disorder: a systematic review and meta-analysis

Background

While numerous previous studies have indicated that nicotine intake results in gray matter and functional brain abnormalities in tobacco use disorder (TUD), the majority of results could not be replicated or even reversed. Consequently, it is important to utilize relevant coordinate data for a comprehensive meta-analysis to identify the shared patterns of structural, functional, and multimodal alternations in TUD.

Method

The present study conducted a systematic retrieval of studies published on PubMed, Web of Science, and Scopus from January 1, 2010, to December 12, 2023, to identify studies on voxel-based morphometry (VBM) and resting-state functional magnetic resonance imaging (rs-fMRI) for TUD. Then, two meta-analyses using the anisotropic seed-based d mapping method were used to detect brain comprehensive alterations in individuals with TUD. Furthermore, two meta-analyses were pooled for multimodal analysis to discover multimodal anomalies. Finally, subgroup analyses were performed to explore the sources of TUD heterogeneity from both methodological and age perspectives.

Result

This study encompassed a total of 25 VBM studies, including 1,249 individuals with TUD and 1,874 healthy controls (HCs), and 35 rs-fMRI studies, including 1,436 individuals with TUD and 1,550 HCs. For rs-fMRI analysis, individuals with TUD exhibited increased intrinsic function in the right cerebellum crus2, left superior frontal gyrus, left inferior parietal gyrus, and left supplementary motor area and decreased intrinsic function in the right gyrus rectus, right superior/middle frontal gyrus, and left inferior frontal gyrus. For VBM analysis, individuals with TUD showed decreased gray matter volume (GMV) in the left superior temporal gyrus, right superior frontal gyrus, right anterior cingulate/paracingulate gyrus, left superior frontal gyrus, and right anterior thalamic region and increased GMV in the right lingual gyrus.

Conclusion

This meta-analysis illustrates structural and functional abnormalities of the default mode network, executive control network, and salience network in individuals with TUD. Multimodal analysis of the right lingual gyrus provided additional information, offering the potential for identifying more therapeutic targets for interventions against TUD.

Brain structural alterations in internet gaming disorder: Focus on the mesocorticolimbic dopaminergic system

AIMS

This study aimed to identify gray/white matter volume (GMV/WMV) alterations in Internet Gaming Disorder (IGD), with a special focus on the subregions of the mesocorticolimbic dopaminergic system and their clinical association.

RESULTS

Compared with healthy controls, IGDs showed bigger GMV in the bilateral caudate and the left nucleus accumbens (NAc), and bigger WMV in the inferior parietal lobule. The comparison of regions of interest (ROI) confirmed increased GMV in the bilateral caudate (including the dorsal anterior, body, and tail) and the left core of NAc in IGD, but no significant WMV alterations in the mesocorticolimbic dopaminergic system. GMVs in the left lateral orbital gyrus of orbitofrontal cortex (OFC) were associated with craving for games, while GMVs in the left anterior insula, right NAc, right caudate, and right OFC were associated with self-control in IGD.

CONCLUSIONS

IGD was accompanied by changed GMV, but not WMV, in the mesocorticolimbic dopaminergic system. GMV in the mesocorticolimbic dopaminergic system may contribute to impaired self-control and craving in IGD.

Sex-Dependent Alterations of Regional Homogeneity in Cigarette Smokers

Biological sex may play a large role in cigarette use and cessation outcomes and neuroimaging studies have demonstrated that cigarette smoking is associated with sex-related differences in brain structure and function. However, less is known about sex-specific alterations in spontaneous brain activity in cigarette smokers. In this study, we investigated the sex-related effects of cigarette smoking on local spontaneous brain activity using regional homogeneity (ReHo) based on resting-state fMRI. Fifty-six smokers (24 females) and sixty-three (25 females) healthy non-smoking controls were recruited. Whole-brain voxelwise 2-way analysis of covariance of ReHo was performed to detect brain regions with sex-dependent alterations on the spontaneous brain activity. Compared to non-smokers, smokers exhibited significant ReHo differences in several brain regions, including the right medial orbitofrontal cortex extended to the ventral striatum/amygdala/parahippocampus, left precuneus, and bilateral cerebellum crus. Smoking and sex interaction analysis revealed that male smokers showed significantly lower ReHo in the right ventral striatum, left cerebellum crus1, and left fusiform gyrus compared to male non-smokers, whereas there are no significant differences between female smokers and non-smokers. Furthermore, the ReHo within the left cerebellum crus1 was negatively correlated with craving scores in male smokers but not in female smokers. Such sex-dependent differences in spontaneous brain activity lays a foundation for further understanding the neural pathophysiology of sex-specific effects of nicotine addiction and promoting more effective health management of quitting smoking.