|Alternative Title||The Psychological and Neural Mechanisms of Reward and Cognitive Control in Internet Addiction|
|Place of Conferral||中国科学院心理研究所|
|Keyword||网络成瘾 网游成瘾 奖赏 认知控制|
Internet addiction (IA) refers to one's inability to control the strong desire to use the Internet, which eventually leads to impairments in psychological, social and educational/work. In the past decade, IA has become more and more serious due to its entertainment and accessibility, especially among teenagers and college students. Internet gaming disorder (IGD), one of the subcategories of IA, has been classified as a mental disorder by the fifth edition of the diagnostic and statistical manual of mental disorders and the eleventh edition of the international classification of diseases. Based on the dual-system of adolescent neurobiological model and self-regulation model, the present paper aimed to explore the psychological and brain mechanisms of the reward and cognitive control system in IA by applying the questionnaire survey, behavior, meta-analysis and magnetic resonance imaging (MRI) technology, and thus provide more evidence for the prevention and treatment of IA. This paper consists of four studies (six experiments), which are stated as follows:
Study 1 (experiment 1):this study collected a total of 416 adolescents data by adopting the questionnaire survey method, and then evaluated the relationship between reward/punishment sensitivity, impulsivity and IA in adolescents, and the mediating roles of coping styles (emotion-focus and problem-focus) and gender among this relationship by using the structural equation model analysis method. The results showed that in boys, individuals with high reward sensitivity and impulsivity had a higher risk of IA, while in girls, individuals with high punishment sensitivity and impulsivity had a higher risk of IA. And individual coping styles played a mediating role in the relationship between reward/punishment sensitivity, impulsivity and Internet addiction, which were gander differences. From the personality traits of dual system perspective, this study revealed the gender difference in the risk factors of IA and its mediating mechanisms.
Study 2 (experiment 2): this study mainly focuses on the IGD population, the most serious subtype of IA. The study is a behavioral experiment, in which a total of 45 adolescents with IGD from an addiction treatment center and 43 matched healthy controls (HCs) were recruited. The mixed gambles task and the stop-signal task were used to explore the risky decision-making (loss aversion) and inhibition control ability in IGD. The results showed that compared with HCs, subjects with IGD had reduced loss aversion and worse inhibitory control ability, and the cluster analysis found that the dysfunctions of the dual-system were only observed in subjects with higher severity of IGD, whereas subjects with relatively lower severity of IGD only showed reduced loss aversion but intact inhibition ability.
Study 3 (experiment 3): this study used the meta-analysis to summarize the previous brain imaging studies on reward and cognitive control system of behavior addiction and substance addiction to examine the neural substrates of the dual-system in addiction. The results showed that the addicted population exhibited stronger activation patterns in brain regions crucial for reward (the striatum and rostral anterior cingulate gyrus), while no consistent abnormalities in cognitive control were found. Further, we found that the dysfunctional reward system of behavior addiction was mainly located on caudate nucleus and pallidum of striatum, which showed strong activation pattern. The dysfunctional reward system of substance addiction located on the rostral anterior cingulate gyrus and caudate, which also showed strong activation pattern. Through this study, we have a sufficient understanding of previous studies on dual-system of addiction, which provides a good foundation for the follow-up investigation of the neural substrates in IA.
Study 4 (experiment 4-6): experiment 4: this part aimed to investigate the neural substrates of reward processing's three phases (reward anticipation, outcome monitoring and choice evaluation) and cognitive control in IGD by applying task-state functional MRI. We recruited 28 college students with IGD and matched 28 HCs. All subjects completed the roulette task and the stop一signal task under functional magnetic resonance imaging scanning. The results showed that compared with HCs, subjects with IGD showed stronger activation patterns in the striatum region (nucleus accumbens, caudate) during the reward anticipation and outcome monitoring phase, which is partly consistent with the findings of study 3. In terms of inhibitory control, consistent with the cluster results of study 2, insufficient activation of in inhibitory control-related region (inferior frontal gyrus) was only found in subjects with high severity of IGD. Experiment _5:this part aimed to investigate the functional connectivity between reward and cognitive control systems in IGD by applying resting-state functional MRI. The sample of the current experiment was same as that of experiment 4. The results showed that compare with HCs, subjects with IGD exhibited weaker functional connectivity between striatum and prefrontal control regions (inferior frontal gyrus and superior frontal gyrus). Experiment 6: this part aimed to investigate the structural alteration of reward and cognitive control systems in IGD by applying structural MRI. The sample of the current experiment was same as that of experiment 4. The results showed that compare with HCs, subjects with IGD only exhibited larger gray matter volume in striatum.
From the perspective of dual-system, the current study 1 revealed the different risk factors among genders and the underlying mechanism, study 2, 3 and 4 suggest that the enhanced reward system is a more stable feature of IGD, and enhanced reward system plays a key role in the development and maintenance of IGD, while the insufficient inhibitory control is related to the severity of IGD, which jointly revealed the imbalance between reward and cognitive control system in IGD. In sum, all these findings might provide important implications for the prevention and intervention of IA, especially IGD.
|王凌霄. 网络成瘾者奖赏与认知控制的心理与脑机制探究[D]. 中国科学院心理研究所. 中国科学院心理研究所,2020.|
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