The changes of intrinsic connectivity contrast in young smokers

Abstract

Abstract Previous studies demonstrated that reward circuit plays an important role in smoking. The differences of functional and structural connectivity were found among several brain regions such as nucleus accumbens, thalamus and frontal lobe. However, few studies focused on functional connectivity in whole-brain voxel level of young smokers. In this study, intrinsic connectivity contrast (ICC) was used to perform voxel-based whole-brain analyses in 55 young smokers and 55 matched non-smokers to identify brain regions with significant group differences. ICC results showed that the connectivity of young smokers in Medial Frontal Cortex (MedFC) showed a significantly lower trend compared with the non-smokers. The seed-based functional connectivityanalysis about MedFC indicated that young smokers showed reduced connectivity between the MedFC and left hippocampus, left amygdala compared to non-smokers. In addition, correlation analysis showed that the ICC of MedFC in young smokers was significantly negatively correlated with Fagerstrom Test for Nicotine Dependence (FTND) and Questionnaire on Smoking Urges (QSU). The functional connectivity of the MedFC was significantly negatively correlated with Pack_years. Moreover, the mediation analysis indicated that ICC of MedFC completely mediated FTND and QSU of young smokers. The results suggest that nicotine accumulation may affect the conmunication of the frontal lobe with the whole brain to some extent, leading to changes in smoking cravings. These results demonstrate the importance of whole-brain analysis and highlight the effectiveness of a completely data-driven approach to the problem. The above research also provides in-depth insights into the mechanism of adolescent smoking addiction and related intervention treatment.