Biol Psychol. 2013 Aug 6. pii: S0301-0511(13)00182-8. doi: 10.1016/j.biopsycho.2013.07.009.
Department of Psychology, Zhejiang Normal University, Jinhua, Zhejiang, Province, P.R.China. Electronic address: [email protected].
Internet addiction disorder (IAD) has raised widespread public health concern. However, the mechanism of Internet addiction remains unclear. In this study, we designed a continuous wins-and-losses task to monitor the mental activities during this process and determine the influence of decisions and their outcomes on subsequent decision making. In behavioral performance, IAD subjects show longer response time and lower repeat rate in decision making than healthy controls. The IAD subjects also exhibit significantly greater Stroop effect than healthy controls. Neuroimaging results suggest that the IAD subjects exhibit increased brain activities in the inferior frontal cortex, insula, and anterior cingulate cortex and decreased activation in the right caudate and right posterior cingulate cortex after continuous wins compared with the healthy controls. In decision making, after continuous losses, the IAD subjects show increased brain activities in the inferior frontal gyrus and decreased brain activation in the posterior cingulate cortex. Thus, we concluded that IAD subjects engage many cognitive activities to finish the decision-making task. As a result, these subjects cannot sufficiently focus on the executive function during this process. They also do not pay adequate attention to considering previous selections and relevant outcomes during decision making. Our results suggest one explanation as to why IAD subjects continue playing online even when faced by severe negative consequences of their behavior.