What makes Internet addicts continue playing online even when faced by severe negative consequences? Possible explanations from an fMRI study

In this study, we designed a continuous wins-and-losses task to monitor the mental activities during decision-making and their effects on subsequent decisions in Internet addiction disorder (IAD) subjects. In behavioral performance, IAD subjects show longer response time, lower repeat rate and greater Stroop effect than healthy controls. In neuroimaging results, IAD subjects show increased brain activities in the inferior frontal cortex, insula, anterior cingulate cortex and decreased activation in the caudate and posterior cingulate cortex after continuous wins than healthy controls. In addition, IAD subjects show increased brain activities in the inferior frontal gyrus and decreased brain activation in the posterior cingulate cortex after continuous losses. Thus, we concluded that IAD subjects engage more cognitive activities to finish the decision-making task. As a result, they 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. (C) 2013 Elsevier B.V. All rights reserved.