Investigating The Role Of Prefrontal Cortex In Prospective Memory:A TMS Study

Prospective memory(PM)refers to a person remembering actions to be taken,and is a type of memory that is relative to retrospective memory.It is related to the plans or goals we set for daily activities and is one of the most important cognitive functions of human beings.Understanding the brain relevance of PM and the factors that influence PM is an important area of research in cognitive neuroscience.The current viewpoint mainly emphasizes the role of frontal polar cortex in the neural control of PM.To date,a large number of neuroimaging studies have investigated the neural basis of PM,and most of which focus on the functional role of the prefrontal cortex(PFC).Although the importance of PFC for higher-order cognitive functions is undisputed,it is not clear about its specific functional role and whether or not there is a functional division.Therefore,the purpose of this article is to use the repetitive transcranial magnetic stimulation(rTMS)method to study the role of two subregions of the prefrontal lobe in prospective memory and the two influencing factors of prospective memory.The research in this paper is mainly divided into two phases: First,we adopted an experimental paradigm including three tasks: oddball task;n-back working memory task;and prospective memory dual-task.TMS was used to temporarily intervene the function of aPFC and DLPFC on the right side of the subjects to investigate the role of aPFC and DLPFC in prospective memory and working memory respectively,and the relationship between working memory and prospective memory was discussed by the contribution of two brain regions to the two kinds of memory.The experimental results showed that compared with the control sites,the stimulation of two target sites interfered with the behavioral performance of the 1-back task in the dual-task with task switching,but had no effect on 1-back of the single-task,indicating that aPFC and DLPFC play a crucial role in cognitive control.In subsequent studies,we designed a dual-task experimental paradigm with high and low loads,and also used rTMS to stimulate the left aPFC and DLPFC respectively to further investigate the role of these two regions in the left hemisphere in prospective memory,and to explore the effects of left and right hemisphere differences and task complexity on prospective memory.Compared with the sham,it was found that the performance of PM task was disturbed under the condition of high load after the stimulation of aPFC.From this,we can conclude that there seems to be hemispheric lateralization in the function of aPFC in the process of PM neural regulation,that is,the left aPFC has a greater contribution to prospective memory.And the more difficult the task,the more difficult the prospective memory implementation.Our results demonstrate the important role of aPFC and DLPFC in cognitive control,and also verify that aPFC is a key brain region for prospective memory.According to our research,we found that the left hemisphere has a greater impact than the right hemisphere.Especially under conditions of high task complexity.