The Cognitive Neural Mechanism Of Intertemporal Choice And Risky Dicision In Internet Gaming Addition

Intertemporal choice and risky decision is the most common and important two types of decision making in People’s Daily life. Intertemporal choice refers to the process of the decision makers weigh the options between the results (gains or losses) at different time points, and then make judgment and choice. Risky decision refers to the process of the decision makers weigh the options between the two or more uncertain results of gains or losses, and then make judgment and choice. Intertemporal choice usually require individual to make choice between an immediate but smaller reward and a delayed but larger reward. The researchers found that compared with the immediate rewards, individuals tend to give delay option smaller weight, the value of delay option has been discounted, this phenomenon is called delay discounting. Risky decision usually require individual to make choice between a fixed but smaller reward and a probability but larger reward. Compared with the larger amount money with low probabilities of occurrence, decision makers prefer to choose the smaller fixed reward, we use probability discounting to explain this phenomenon. There is a definite relation on the concept between intertemporal choice and risky decision, Because the result in the future time of intertemporal choice has certain uncertainty, so the present value of the delayed reward including both the time delayed discounting and probability discounting. In addition, intertemporal choice and risky decision have certain similarity in the following four aspects:the premise and hypothesis of calculation model; some corresponding abnormal phenomenon of two kinds of decision making; the influence of time,and risk to two kinds of decision making; the similarity between the delayed discounting and probability discounting. So some studies examine the features of delay discounting and probability discounting in the same participants simultaneously to explore the general brain regions and specific brain regions.In the operating level addiction can be defined as:Even be explicitly asked to make a different choice, the individual still continue to make the nonadaptive choice. The addicted probably can be divided into two classes:Substance addiction and addictive behaviors (including the gambling addiction and Internet addiction). Usually, in the face of his thirst for drugs or attract behavior, addicts know if they choose to continue medication or gambling will bring themselves a lot of negative consequences, but they still choose to do. A large number of studies have found that when the drug addicts making decisions, they prefer short-term benefit and regardless of long-term loss. Studies have found that gambling addiction disorder has similar decision-making obstacles. This decision-making obstacles of the addicted was called myopia for the future by the researchers. Internet addiction disorder refers to the individual use the internet persistently or out of control, even they know this will bring some negative psychological or social consequences. Internet gaming disorder (IGD) was one of the three subtypes of internet addition disorder, which has been included in Section IE of the DSM-5 as a condition warranting further study in May 2013. Because the IGD has a certain similarity whit the substance addiction and gambling addiction, and there are a small amount of researches had confirmed that internet gaming disorder also has Decision-making obstacles, such as myopia for the future and impaired ability of risk assessment at behavioral level. But there is no research to explore the decision-making obstacles of the IGD at the neural level. Considering the relation on the concept between delayed reward and probability reward, this study intends to use functional magnetic resonance imaging to investigate the features of delay discounting and probability discounting in IGD, which can help us learn more about the neural mechanisms of decision-making obstacles in IGD.The first experiment investigated the features of delay discounting by the delay discounting task, and the results showed that IGD subjects show decreased activation than healthy control (HC) in the dorsolateral prefrontal cortex (DLPFC) and the bilateral inferior frontal gyrus (EFG). The second experiment investigated the features of probability discounting by the probability discounting task, and the results showed that IGD participants show decreased activation in the inferior frontal gyrus and the precentral gyrus when choosing the probabilistic options than HC. Synthesize the data analysis results of the two experiments, we can get the following four conclusions:Firstly, the IGD participants’ability to represent the delayed rewards was impaired relative to the HC. And the higher severity of IGD, the more impaired ability to represent the delayed rewards.Secondly, the IGD participants’ability to self control was impaired relative to the HC. And the higher severity of IGD, the more impaired ability to self control.Thirdly, the IGD participants tend to take risks relative to the HC. And the severity of addiction will affects the degree of taking risks in IGD. the IGD participants is not sensitive to the possible losses, and use less effort to perceive possible losses.Fourthly, the IGD participants’ ability to assess risk was impaired relative to the HC. This may be related to their risk-taking tendency.