Match The Working Memory Processing Impact Scenarios Extracted Brain Mechanism

Working memory has been described as a hub of human cognition,and it is the most active one in the fields of the cognitive psychology and cognitive neuroscience.The multi-component working memory model which was first put forward by Baddeley has been supported by the results of many experimental studies,but the relationship between working memory and episodic memory has not been elaborated.And in particular,it is a controversial issue of how working memory influences episodic long-term memory.Now,the research on the relationship between working memory and episodic memory has attracted wide attention,and become a focal problem in the field of memory research.Basing on previous studies,this study explores the impact of working memory encoding on retrieval using the delayed match-to-sample paradigm by ERP and fMRI techniques,aimed to provide support for the integration research of brain mechanisms in different memory system.Using the event-related ERP technology with high time resolution,this study firstly investigated the ERP mechanisms of how the encoding of the identical matches, categorical matches,and non-matches between pictures and words including cross-forms and within-form effect episodic retrieval,basing on the delayed match-to-sample paradigm.We hoped to track the different brain mechanisms of working memory among the different experimental conditions from time epoch by comparing the results of episodic retrieval,in order to find out what impacts the episodic retrieval during the encoding process.And then,we used the event-related fMRI technology with high spatial resolution,and researched the brain activation of the identical matches,categorical matches,and non-matches by the delayed match-to-sample paradigm in depth.Finally,we would analysis the fMRI results together with the related ERP results,in order to make clear the brain mechanism of cross-form matches between pictures and words. The main results that we have obtained are as follows:(1) In the stage of episodic retrieval,it shows a similar pattern of the results during episodic retrieval stage between pictures or words matches from within-forms.The accuracy rates of identical matches old are remarkably lower than those of categorical matches old and non-matches old,and the reaction time of those are significantly slower than those of them.While,in the experiment of pictures and words matches from cross-forms,the accuracy rates of identical matches old are remarkably higher than those of categorical matches old and non-matches old,and the reaction time of those are significantly faster than those of them.And the same trends are showed up in the ERPs results,campared with the amplitude of categorical matches old and non-matches old,the amplitude of identical matches old are significantly more positive than categorical matches old and non-matches old in the experiment of pictures and words cross-form matches,but it is contrary in the other two experiment of pictures and words matches from within-forms.As for the categorical matches old and non-matches old, they are closesimilarto in the waveform,and effect from the impact of the encoding forms. In a word,it is dissociative between the espisodic retrieval results of cross-form and within-form matching encoding,regardless of the behavior results or ERPs results.(2)Tracing back to the working memory encoding stage,we find that the P300 component on wave of the picture-word identical matches shows earlier than those of picture-picture and word-word identical matches,and it has two P300 peaks.While, there are not two P300 peaks on the waves of picture-picture and word-word identical matches.In spite of the latency of the P300 on the wave of picture-word identical matches is shorter than those of the picture-picture and word-word identical matches,it down to the baseline faster than those of the other conditions after 600ms,and the reaction time is also significantly faster than the other conditions,which shows repetition inhibition effect. (3) As to the old-new effects in the episodic retrieval,there are similar pattern on the old-new effects of the picture-word and word-word identical matches,but the old-new effect of picture-picture identical matches shows different characteristics,especially after 600ms.(4) In the results of the fMRI experiment,the activation level of picture-word identical matches condition is less than that of the categorical matches and non-matches conditions in precuneus,frontal and occipital areas,which shows repetition inhibition phenomenon.Campared among the three match conditions,there are more activation levels of non-matches than identical matches in precuneus,and there are more activation areas for non-matcher than that of the categorical matches in frontal,occipital and medial temporal lobes.And,there are more activation areas for the categorical matches in frontal,parietal and medial temporal regions in comparison with the other two conditions.Based on the above findings,we carried out in-depth discussion and analysis to them from the behavior and the temporal and spatial processing mechanisms of brain cognitive neuroscience about how the different match conditions influence the episodic retrieval,and produced the following conclusions:(1) It is asymmetry between working memory encoding and episodic memory retrieval.The retrieval is the repetitive activation or ecphory activation of the encoding, but it is not the simple recovery to the encoding,especially in the episodic long-term memory.(2) There are different mechanisms on the impacts of episodic long-term retrieval between the identical matches and categorical matches encoding in the working memory. The identical matching have facilitative or inhibitory influence on the episodic retrieval depending on the forms of encoding materials,while compare to the non-match condition,there is no such effect on semantic related matching in the episodic retrieval.(3) In the working memory encoding,the process of cross-matching and within-matching between pictures and words may share with the same semantic representation system,and there may exist the specific process defference due to the impact of specific forms.(4) The different matching conditions in the working memory lead to different results of episodic retrieval,and the key factor may lie in the P300 component.(5) The function of precuneus may reflect the semantic matching process.In this study,we investigated the relationships between encoding and retrieval,as well as working memory and episodic memory,by using the delayed match and episodic retrieval paradigm,and further confirmed that the retrival is not the simple recovery of the encoding,and enrich the past researches on brain mechanism in these fields.And,it also provides supports for the repetition inhibition theory.At the same time,the results of this study also provided the basis for us to explain for some phenomenon,such as learning and memory and other phenomenon that occurred in the daily life.