Age-related and individual variations in altered prefrontal and cerebellar connectivity associated with the tendency of developing internet addiction

Abstract

Internet addiction refers to problematic patterns of internet use that continually alter the neural organization and brain networks that control impulsive behaviors and inhibitory functions. Individuals with elevated tendencies to develop internet addiction represent the transition between healthy and clinical conditions and may progress to behavioral addictive disorders. In this network neuroscience study, we used resting-state functional magnetic resonance imaging (rs-fMRI) to examine how and whether individual variations in the tendency of developing internet addiction rewire functional connectivity and diminish the amplitude of spontaneous low-frequency fluctuations in healthy brains. The influence of neurocognitive aging (aged over 60 years) on executive-cerebellar networks responsible for internet addictive behavior was also investigated. Our results revealed that individuals with an elevated tendency of developing internet addiction had disrupted executive-cerebellar networks but increased occipital-putamen connectivity, probably resulting from addiction-sensitive cognitive control processes and bottom-up sensory plasticity. Neurocognitive aging alleviated the effects of reduced mechanisms of prefrontal and cerebellar connectivity, suggesting age-related modulation of addiction-associated brain networks in response to compulsive internet use. Our findings highlight age-related and individual differences in altered functional connectivity and the brain networks of individuals at a high risk of developing internet addictive disorders. These results offer novel network-based preclinical markers of internet addictive behaviors for individuals of different ages.

Keywords: ALFF; aging; functional connectivity; internet addiction tendency.

FIGURE 1

The connectome representing resting‐state functional brain connectivity of the brain of participants with the tendency of developing internet addiction. (a) Significant effects of the tendency of developing internet addiction on the brain as represented using a three‐dimensional glass brain. The cyan dots represent brain regions and the red and blue connections represent positive and negative connections, respectively between the brain regions. (b) Functional connectome representing the effect of a tendency of developing internet addiction on the human brain. The results for (a) and (b) were thresholded at p < .05 with a false discovery rate correction applied for multiple testing. Cereb 1r: right cerebellum (crus 1b); Cereb 2r: right cerebellum (crus 2b); OP l: left occipital pole; OP r: right occipital pole; SCC l: left supra‐calcarine cortex; SCC r: right supracalcarine cortex; pSTG l: left superior temporal gyrus; PP l: left planum polare; FO l: right frontal opercular cortex; Putamen r: right putamen; Ver 3: vermis (lobule 3); Cereb 10 L: left cerebellum (crus 10); AG r: right angular gyrus; sLOC l: left lateral occipital cortex; L: left; R: right

FIGURE 2

The connectome representing resting‐state functional brain connectivity of a tendency of developing internet addiction for younger adults and older adults. (a) Significant effects of the tendency of developing internet addiction on the brain, as represented using a three‐dimensional glass brain in (A) younger adults and (B) older adults. The cyan dots represent brain regions and the red and blue connections represent positive and negative connections, respectively, between the brain regions. (b) Functional connectome representing the effect of a tendency of developing internet addiction on the human brain in (A) younger adults and (B) older adults. The results for (a) and (b) were thresholded at p < .05 with a false discovery rate correction applied for multiple testing. For younger adults: PostCG r: right postcentral gyrus; PreCG r: right precentral gyrus; SPL r: right superior parietal lobule; IFG oper l: left inferior frontal gyrus (operculum); Accumbens l: left accumbens; Cereb 3r: right cerebellum (crus 3); Cereb 10r: right cerebellum (crus 10); Cereb 7r: right cerebellum (crus 7); Ver 10: vermis (lobule 10). For older adults: Putamen r: right putamen; PO r: right parietal operculum; Ver 9: vermis (lobule 9); SCC l: left supra calcarine cortex; SCC r: right supracalcarine cortex; L: left; R: right

FIGURE 3

The Analysis of the effect of individual differences on brain regions associated with the tendency of developing internet addiction, showing a significant decrease in the amplitude of low‐frequency fluctuations (ALFFs) across all participants. Analysis of the effect of individual differences on the tendency of developing internet addiction and associated brain regions showed a significant decrease in the ALFFs in all participants. The brain regions that showed reduced ALFFs were the right precentral gyrus, bilateral supplementary motor area, right superior frontal gyrus, bilateral thalamus, right caudate; anterior cingulate gyrus, right lingual gyrus, and regions of the cerebellum. The clusters were voxel threshold‐corrected at p < .05 and cluster threshold‐corrected at p < .05, with a false discovery rate correction applied for multiple testing. The color bar indicates the range of the t value; R: right

FIGURE 4

Analysis of the effect of age on brain regions associated with the tendency of developing internet addiction, showing a significant increase in the amplitude of low‐frequency fluctuations (ALFFs) in older healthy adults compared with younger healthy adults. The analysis of the effect of age on brain regions associated with the tendency of developing internet addiction showed a significant increase in the amplitude of ALFFs in older adults compared to younger adults. The regions with reduced ALFFs were the posterior cingulate gyrus and precuneus cortex whereas increased ALFFs were found in the right temporal pole, right frontal orbital cortex, right parahippocampal gyrus, and right amygdala. The clusters were voxel threshold‐corrected at p < .05 and cluster threshold‐corrected at p < .05, with a false discovery rate correction applied for multiple testing. The color bar indicates the range of the t value; R: right