The episodic effect suggests that episodic prospection (imagining future events) can effectively reduce time discounting, the propensity to discount the value of delayed rewards relative to immediate ones. However, less clear is how episodic prospection modulates time preference. As engagement in episodic prospection usually evokes prospective emotions, it was proposed that episodic prospection might work by inducing prospective emotions. Although one previous study has attempted to provide evidence to the emotional account of the episodic effect, shortcomings in its experimental design make its conclusion questionable. In this study, we replicated previous experimental design with improvements to further test the effects of prospective emotion on time preference. By manipulating the emotional valency associated with episodic prospection in a delay discounting task, we found that positive episodic prospection attenuated time discounting; negative episodic prospection exacerbated time discounting; and episodic prospection did not shift time preference when prospective emotion is removed. These results were essentially identical to the result of the previous study. Together, these studies suggested that the effects of episodic prospection depended on prospective emotion. Thus, one cannot ignore prospective emotion if counting on episodic prospection to combat humans' impulsive behaviours.

Procrastination, the voluntary and irrational delay of an intended course of action, has troubled individuals and society extensively. Various studies have been conducted to explain why people procrastinate and to explore the neural substrates of procrastination. First, research has identified many contributing factors to procrastination. Specifically, task aversiveness, future incentives, and time delay of these incentives have been confirmed as three prominent task characteristics that affect procrastination. On the other hand, self-control and impulsivity have been identified as two most predictive traits of procrastination. After identifying contributing factors, two important theories proposed to explain procrastination by integrating these factors are reviewed. Specifically, an emotion-regulation perspective regards procrastination as a form of self-regulation failure that reflects giving priority to short-term mood repair over achieving long-term goals. However, temporal motivation theory explains why people's motivation to act increases when time approaches a deadline with time discounting effect. To further specify the cognitive mechanism underlying procrastination, this study proposes a novel theoretical model which clarifies how the motivation to act and the motivation to avoid vary differently when delaying a task, explaining why people decide not to act now but are willing to act in the future. Of note, few recent studies have investigated neural correlates of procrastination. Specifically, it was revealed that individual differences in procrastination are correlated with structural abnormalities and altered spontaneous metabolism in the parahippocampal cortex and the prefrontal cortex, which might contribute to procrastination through episodic future thinking or memory and emotion regulation, respectively.

Although procrastination has troubled people consistently, there is a lack of systematic theories to explain this behavior. The present study aims to propose and validate a temporal decision model to explain procrastination. The temporal decision model predicts that people will procrastinate on a task so long as the aversiveness of a task outweighs the utility of future incentive outcomes that this task can yield. Specifically, people perceive less aversiveness from a task when this task is scheduled in the future than in the present but expect that they can perceive higher utility from the incentive outcome in the future than in the present. Consequently, people are reluctant to do this task in the present but expect that they are willing to do it in the future (i.e., procrastination). We tested these predictions by measuring perceived task aversiveness, outcome utility, and decision for real-life tasks when the same tasks were scheduled with different delays. The results demonstrate that people expect that they would procrastinate a task as long as perceived task aversiveness is stronger than outcome utility and would stop procrastinating when perceived task aversiveness becomes comparable with outcome utility. Furthermore, people perceive less task aversiveness when the task is scheduled further away and expect that outcome utility would be higher when time gets closer to the delivery of outcome in the future. The present study explains procrastination by revealing how perceived aversiveness from a delayed task and expected outcome utility generate asymmetric decisions between the present and the future.

AIM:To investigate the hepatitis B virus (HBV) x gene (HBx) state in the tissues of HBV-related hepatocellular carcinoma (HCC) in Chinese patients and whether there were particular HBx mutations.

Background: The hepatitis B virus x gene (HBx) is a promiscuous transactivator implicated in the development of hepatocellular carcinoma (HCC). The present study was designed to investigate the molecular events regulated by HBx. Methods: Genomic and proteomic expression profiling was performed in Huh7 HCC cells transfected with HBx mutants with a C-terminal deletion. The gene and protein expression of wingless-type murine-mammary-tumour virus (MMTV) integration site family, member 5A (Wnt-5a) was validated by analyses of reverse transcription–polymerase chain reaction (RT–PCR), real-time RT–PCR, western blot and immunohistochemistry. Results: Differentially expressed genes and proteins were found in the transfected Huh7 HCC cells; most of them were involved in transcriptional regulation, although others including oncogenes or tumor suppressor genes, and molecules involved in cell junctions, signal transduction pathways, metabolism or the immune response were also observed. The expression of the Wnt-5a gene was elevated >10-fold in Huh7 cells transfected with the HBx3′-30 amino acid deletion mutant. However, the expression was downregulated by the transfection with the HBx3′-40 amino acid deletion mutant. The changes in Wnt-5a expression were also observed in human HCC tissues, compared with corresponding non-cancerous liver tissues. A negative correlation was found between the expression of Wnt-5a and HBx COOH mutations in HCC tissues. Conclusions: HBx mutants may participate in the development and progression of HCC, at least in part through the Wnt-5a pathway.