The Effect And Its Neural Mechanism Of Personal Goals On Episodic Future Thinking Of Individuals With Depressive Tendency

The episodic future thinking is the ability of individuals to project themselves into the future and imagine the future.However,there is the abnormality of weakening positive expectation and strengthening negative expectation in depressive individuals’ episodic future thinking,which will increase people’s willingness of committing suicide.As a self-based cognitive process,episodic future thinking is influenced by personal goal.Although,existing studies have explored the influence of personal goal relevance on the likelihood of depressive individuals’ episodic future thinking,they ignored the fact that vividness and reaction time are also important indicators of abnormal of episodic future thinking.In addition,there is no clear conclusion about the effects of internal factors of personal goal(i.e.,goal simulation method and goal difficulty)on episodic future thinking in depressive individuals.Therefore,the purpose of this study was to explore how the external and internal factors of personal goals influence performed on the depressive individuals’ episodic future thinking regarding positive and negative future events.In this study,three experiments were performed.The experiment 1 used the word-cuing paradigms to investigate the influence of the personal goals’ relevance on the episodic future thinking in depressive and non-depressive individuals.The results showed that compared with the non-depressive individuals,the depressive individuals showed a decrease in exception and vividness of positive goal-related events and an increase in exception and decrease in vividness of negative expectations.However,when it comes to events unrelated to personal goal,the depressive individuals showed the exception of negative expectation enhancement.In terms of reaction time,the depressive individuals had a significantly increased when they thinking the negative events related to personal goal compared with the events unrelated to personal goal.The experiment 2 used the word-cuing paradigms to investigate the influence of the goal simulation method on episodic future thinking and its neural mechanism in depressive and non-depressive individuals.The results showed that compared with the non-depressive individuals,the depressive individuals tended to decrease their expectations of positive events and increase their expectations of negative events after the process simulation.However,we found no evidence that the depressive individuals showed disfunction on dealing with events simulated by outcome.The results of f NIRS showed that the interaction of goal simulation method and emotion valence focuses on the dorsolateral prefrontal cortex and the inferior frontal gyrus.The interaction of goal simulation method and depression focused on the left frontopolar area.However,the study did not find the interaction between group(depressive group,non-depressive group),goal simulation method and emotion valence of event.The experiment 3 also used the word-cuing paradigms,combined with f NIRS technology to investigate the effects of goal difficulty and goal simulation method on episodic future thinking of depressive individuals.The results showed that for easy personal goals,the expectation of future positive events was increased,and the expectation of future negative events was decreased after the outcome simulation(in contrast to the process simulation).However,for difficult goals,the process simulation and the outcome simulation had no significant difference in the influence of positive and negative future events.In terms of reaction time,depressive individuals spent significantly longer time imagining negative events than positive events.The reaction time of the process simulation for the difficult goal is longer than the outcome simulation.Based on the research,it concluded that(1)the abnormality in depressive individuals’ episodic future thinking on positive events were moderated by the relevance of the personal goals,which showed a decrease in exception and vividness of positive goal-related events.In addition,the abnormality in depressive individuals’ episodic future thinking on negative events showed a general increase in exception and a decrease in vividness of personal goal-related negative events.(2)The abnormality in depressive individuals’ episodic future thinking were moderated by the goal simulation method,which showed that the process simulation could enhance the negative expectation and weaken the positive expectation.Meanwhile,the dorsolateral prefrontal cortex and the inferior prefrontal gyrus play a role in the planning generation of positive events,while the left frontopolar area is more active in the outcome simulation of the depressive individual,which has a special alienation for negative emotions.(3)The influence of goal simulation method on episodic future thinking was moderated by the goal difficulty,which showed that the outcome simulation could enhance the expectation of simple positive goals and weaken the expectation of simple negative goals.