Resting-state functional connectivity alterations of ventral tegmental area in adult male smokers: a functional magnetic resonance imaging study / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate the alterations of resting-state functional connectivity (RSFC) in ventral tegmental area (VTA) and substantia nigra (SN) among male smokers, and its correlation with clinical characteristics of smoking.Methods:The resting-state functional magnetic resonance data of 131 subjects recruited from January 2014 to December 2018 were analyzed retrospectively, including 76 smokers (smoking group) and 55 non-smokers (control group). VTA/SN was selected as regions of interest (ROI), and then calculated RSFC between VTA/SN and the whole brain.Based on SPM12 software, independent sample t-test was conducted to compare the differences in RSFC between smoking group and control group.Based on SPSS 22.0 software, Pearson correlation analysis was used to investigate the relationships between the RSFC of brain regions with significant differences and Fagerstr?m test for nicotine dependence (FTND) score, pack-year of smokers. Results:Compared with control group, the results showed decreased RSFC between VTA and the brain regions related default mode network (DMN)(including posterior cingulate cortex, right anterior cuneiform lobe, bilateral superior temporal gyrus, right middle temporal gyrus and right inferior parietal lobule), and regions of limbic system(including right marginal lobe and right angular gyrus), right calcarine (MNI x, y, z=24, -55, -14) and left insula(MNI x, y, z=-35, -11, 9) in smoking group(GRF corrected, voxel level P<0.005, cluster level P<0.05). Taking SN as the seed, there was no significant difference between smoking group and control group ( P>0.05). RSFC of VTA-left superior temporal gyrus was positively correlated with pack-year( r=0.243, P=0.034) and FTND ( r=0.282, P=0.014). VTA-left insula RSFC was positively correlated with FTND ( r=0.316, P=0.006). Conclusion:The RSFC in the mesolimbic system and the VTA-DMN circuit exist abnormal changes in smokers.To some extent, it may explain the reward deficits and dysfunction of emotion regulation in smokers, which may provide clues for further understanding the mechanism of tobacco addiction.