Effects of smartphone restriction on cue-related neural activity

Abstract

With the increasing popularity of smartphones in the past decades, physical, social, and psychological consequences of excessive smartphone use (ESU) have been increasingly debated. Cue-reactivity (CR) has been discussed as a core mechanism driving this behavior, and previous studies have highlighted distinct neural mechanisms underlying CR in individuals with ESU. Here, we used a functional MRI (fMRI) CR-paradigm to investigate the effects of smartphone restriction over 72 h in 25 young adult smartphone users. The CR-task used contrasts of images showing smartphones vs. neutral stimuli and active vs. inactive smartphones. Region-of-interest based correlations with psychometric scores were performed, and activity changes after 72 h were investigated on a neurochemical level using neurotransmitter probability maps. CR-related brain activity changes over time were most prominent in the nucleus accumbens and anterior cingulate cortex (p < 0.001). Such changes were significantly associated with dopamine- and serotonin-receptor probabilities (p_FDR < 0.05). Significant associations between parietal cortex activity and craving were detected (p < 0.05). This study provides evidence for CR-related modulation of neural activity in key regions of salience, motor-inhibition, and reward processing after 72 h smartphone restriction. The identified neural mechanisms may substantially promote addictive behavior in people at risk for ESU.