Altered Gray Matter Volume and Resting-State Connectivity in Individuals With Internet Gaming Disorder: A Voxel-Based Morphometry and Resting-State Functional Magnetic Resonance Imaging Study

Abstract

Neuroimaging studies on the characteristics of individuals with Internet gaming disorder (IGD) have been accumulating due to growing concerns regarding the psychological and social problems associated with Internet use. However, relatively little is known about the brain characteristics underlying IGD, such as the associated functional connectivity and structure. The aim of this study was to investigate alterations in gray matter (GM) volume and functional connectivity during resting state in individuals with IGD using voxel-based morphometry and a resting-state connectivity analysis. The participants included 20 individuals with IGD and 20 age- and sex-matched healthy controls. Resting-state functional and structural images were acquired for all participants using 3 T magnetic resonance imaging. We also measured the severity of IGD and impulsivity using psychological scales. The results show that IGD severity was positively correlated with GM volume in the left caudate (p < 0.05, corrected for multiple comparisons), and negatively associated with functional connectivity between the left caudate and the right middle frontal gyrus (p < 0.05, corrected for multiple comparisons). This study demonstrates that IGD is associated with neuroanatomical changes in the right middle frontal cortex and the left caudate. These are important brain regions for reward and cognitive control processes, and structural and functional abnormalities in these regions have been reported for other addictions, such as substance abuse and pathological gambling. The findings suggest that structural deficits and resting-state functional impairments in the frontostriatal network may be associated with IGD and provide new insights into the underlying neural mechanisms of IGD.

Keywords: Internet gaming disorder; caudate nucleus; functional connectivity; middle frontal gyrus; resting-state functional magnetic resonance imaging; voxel-based morphometry.

Figure 1

Voxel-based morphometry (VBM) analysis. (A) Different gray matter volumes between the IGD group and HC (p < 0.05, false discovery rate-corrected) (MNI coordinates: L caudate, −8, 14, 10; R MFG, 44, 51, 8; L MFG, −37, 45, 20). (B) VBM correlation analysis (p < 0.01) (MNI coordinates: L caudate, −9, 8, 15). Abbreviations: HC, healthy controls; IAT, Internet addiction test; IGD, Internet gaming disorder; L, Left; MFG, middle frontal gyrus; R, right; MNI, Montreal Neurological Institute.

Figure 2

Functional connectivity analysis. (A) Different brain connectivity between the IGD group and HC (p < 0.05, FDR corrected) (MNI coordinates: L caudate, −9, 8, 15; R/L PCG, 0, -28, 44; R MFG, 35, 12, 40; L precuneus, −16, −56, 26). (B) Correlation analysis between IGD severity and the functional connectivity value (p < 0.05, FDR corrected) (MNI coordinates: L caudate, −9, 8, 15; R MFG, 22, 36, 34). Abbreviations: HC, healthy controls; IAT, Internet addiction test; IGD, Internet gaming disorder; L, Left; MFG, middle frontal gyrus; PG, postcingulate gyrus; R, right; FDR, false discovery rate; MNI, Montreal Neurological Institute; PCG, posterior cingulate gyrus.