Interaction Between Smoking and Internet Gaming Disorder on Spontaneous Brain Activity

Figure 1. Results of ANCOVA analysis controlling for age, gender, educational level, and head motion. Brain regions showed group differences among the four groups of healthy controls, smokers, internet gaming disorder (IGD), and IGD-Smoking individuals in amplitude of low-frequency fluctuation (ALFF) (p < 0.05, FWE-corrected). The brain regions mainly involved in the right medial pre-frontal cortex (MPFC, i.e., orbital frontal gyrus and anterior cingulate cortex) extending to ventral striatum, bilateral cerebellar, and visual-related regions (i.e., lingual and calcarine gyrus and cuneus) as well as the left temporal gyrus.

Figure 2. Post-hoc analyses of ALFF values among the four groups. (A) The brain regions involved in the right MPFC/ventral striatum. ALFF in smoking group was significantly higher than healthy group (p = 3.61 × 10−15) while no significant ALFF differences between IGD-Smoking and IGD group were found (p = 0.439). There were no significant ALFF differences between IGD group and healthy group (p = 0.441) while IGD-Smoking group showed significantly lower ALFF than smoking group (p = 1.16 × 10−12). Moreover, ALFF in smoking group exhibited significantly higher value than IGD group (p = 5.55 × 10−8). (B) The brain regions involved the bilateral cerebellar and visual-related regions. ALFF in smoking group was significantly lower than healthy group (p = 1.17 × 10−7) while the difference between IGD–Smoking and IGD group did not survive the Bonferroni correction at p < 0.0083 (p = 0.038). No significant ALFF differences between IGD and healthy group was found (p = 0.081) while IGD-Smoking group showed significantly higher ALFF than smoking group (p = 2.32 × 10−7). (C) The brain regions involved the left temporal gyrus. ALFF in smoking group was significantly higher than healthy group (p =…

Figure 3. The correlation analysis between ALFF values and clinical characteristics controlling for age, gender, educational level, and head motion. The ALFF value in the smoking group was associated positively with SAS (A), SDS (B) and motor impulsiveness dimension of BIS-11 scores (C) in the right MPFC/ventral striatum. (D) The ALFF value in the smoking group had a trend toward negative correlation with SDS score in the bilateral cerebellar and visual-related regions of lingual and calcarine gyrus and cuneus. (E)The ALFF value in the smoking group was associated positively with SAS score in the left temporal gyrus.