慢性应激指个体因长期处于紧张的学习或工作环境而体验到的持续压力状态。不确定性决策作为现实生活中的常见决策形式,其认知机制复杂且易受应激状态影响。研究通过行为实验,并结合静息态功能磁共振成像 ( rs-fMRI ) 技术,研究发现:慢性应激主要通过影响腹内侧前额叶 ( vmPFC ) 和腹侧纹状体 ( VS ) 的分数低频振幅 ( fALFF ) 值,削弱个体的损失规避倾向,进而损害其不确定性决策能力。研究结果揭示了慢性应激影响不确定性决策的行为特征与神经机制,为理解应激相关认知障碍提供了新证据,并为未来干预研究提供了潜在的神经靶点。
Chronic stress refers to the sense of tension and loss of control that individuals experience when exposed to stressful learning and overloaded work for a long period of time. It affects not only individual health but also cognitive mechanisms, impairs executive function and autonomous activities, and increases risk-taking behavior. Stress and decision making are both common psychological processes in life, and there are numerous studies on the relationship between them, but most of them are induced acute stress in the laboratory. However, chronic stress is the closest experience to people's real life and the most natural type of stress. Due to the difficulty of inducing chronic stress, it is not easily controlled as an independent variable and is rarely seen in research. Chronic stress can change the cognitive and emotional regulation mode of individuals, thereby affecting decision-making behavior. The mechanism of its influence is an urgent mystery. This study can provide a new theoretical framework and research ideas for neuroscience by thoroughly examining the mechanisms that chronic stress affects decision making. This helps us better understand how brain responds to chronic stress and provides a foundation for future research.
In this study, two laboratory experiments were set up in college students. Experiment 1, the first phase of the experiment, used a large sample to measure chronic stress using the Perceived Stress Scale (PSS), after which the college students were asked to do decision-making tasks. After balancing the gender variables, the subjects were divided into two groups according to their PSS scores. The data of 1,000 college students who met the requirements of the experiment were collected and used to analyze the differences in decision performance. To further explore the neural mechanism of chronic stress on decision making, experiment 2 was set up. Experiment 2 repeated the procedure of Experiment 1, with the only difference that Experiment 2 added post-task functional magnetic resonance imaging (fMRI) for resting state brain scanning. It should be noted that although experiment 2 is a second-stage study, the subjects of experiment 1 are not the same group of college students. All subjects were exposed to IGT test content for the first time, and took a 10-minute rest after arriving at the laboratory, during which no communication was allowed. Then the PSS measurement was completed on the computer, and after the test, the IGT test was completed by resting at the original position for 10 minutes, and finally the fMRI scan was performed for 8 minutes. During the scan, the subjects were instructed to keep their eyes open and stay awake, and not to think about anything.
Experiment 1 showed that there were differences in IGT between subjects with high and low stress levels. The group with high chronic stress was prone to making more risky decisions. fMRI resting state scanning was performed in experiment 2, and the behavioral results were consistent with experiment 1. That is, chronic stress was proportional to risk propensity and inversely proportional to loss avoidance ability. In experiment 2, whole brain analysis showed that vmPFC and VS were more active, and the significance level was.001. This result proves the control effect of vmPFC and VS on loss avoidance. Further data analysis found that chronic stress affects loss avoidance in individuals by altering resting state function of the brain, primarily in the ventromedial prefrontal (vmPFC) and ventral striatum (VS) regions, leading to dysregulation of decision making.
This study reveals that chronic stress negatively affects loss avoidance in individuals by altering the resting state function of the brain, primarily in the ventromedial prefrontal and ventral striatum (VS) regions, leading to the emergence of dysdecision-making. Under the influence of the ventromedial prefrontal and ventral striatum (VS) regions, individuals were more likely to avoid losses than pursue possible gains when faced with a decision. This tendency can lead to irrational and unstable decisions, making individuals more vulnerable to potential risks and negative outcomes.