工作记忆匹配加工影响情景提取的脑机制研究

【作者】 张运红；

【导师】 郭春彦；

【作者基本信息】 首都师范大学 ， 发展与教育心理学， 2009， 博士

【摘要】 工作记忆被形容为人类的认知中枢,是当前认知心理学和认知神经科学中最活跃的研究领域之一。最早由Baddeley提出的工作记忆多成分模型得到了大量实验研究的支持,但工作记忆和情景记忆的关系则一直未能得到详细阐述,尤其是工作记忆对长时情景提取的影响机制还存在诸多争议。目前有关工作记忆和情景记忆关系的研究引起广泛关注,并成为当前记忆研究的一个热点问题。本研究拟在以往研究的基础上,利用ERP和fMRI技术,采用工作记忆延迟匹配样本范式考察工作记忆编码对提取的影响,希望为不同记忆系统脑机制的整合研究提供支持。本研究首先利用具有高时间分辨率的事件相关ERP技术,采用工作记忆延迟匹配样本范式探讨图和词的跨形式与同形式名字匹配、类别匹配和不匹配编码对情景提取影响的ERP机制,目的在于比较不同形式不同内容匹配加工影响下情景提取的ERPs差异,并追踪编码时大脑加工时程的区别,考察这种工作记忆匹配加工影响情景提取的脑机制。其次,利用具有高空间分辨率的事件相关fMRI技术,进一步考察图和词的名字匹配、类别匹配和不匹配在工作记忆延迟匹配样本任务中的大脑激活情况。最后,我们将ERP和fMRI结果结合起来分析影响情景提取的图-词匹配加工的脑机制。通过分析,得到以下研究结果:(1)情景提取阶段,对词词和图图匹配编码的提取呈现出类似的结果模式,名字匹配旧的正确率显著低于类别匹配旧和不匹配旧,反应时也显著慢于类别匹配旧和不匹配旧。而在图-词延迟匹配编码影响下,名字匹配旧的正确率显著高于类别匹配旧和不匹配旧,反应时显著快于类别匹配旧和不匹配旧。ERPs结果表现出同样的趋势,与类别匹配旧和不匹配旧条件相比,对图-词匹配加工提取的名字匹配旧波幅更正,而对词词和图图匹配加工提取的名字匹配旧波幅更负。三个ERP实验中,类别匹配旧和不匹配旧的波形趋近一致,不受编码形式的影响。总的来说,不管是行为结果,还是ERPs结果,跨形式与同形式工作记忆匹配加工对情景提取的影响结果不同。(2)追溯工作记忆编码阶段,发现,在ERPs上,图-词名字匹配条件的P300成分出现得最早,且存在P300双峰;而词词和图图名字匹配条件下不存在P300双峰,虽然潜伏期早于类别匹配和不匹配,但600ms之后很快回到基线,反应时也显著快于类别匹配和不匹配,表现出重复抑制效应。(3)在情景提取的旧新效应上,图-词跨形式匹配和词词同形式匹配表现出一致性,而图图同形式匹配加工的旧新效应表现出不同的特点,主要体现在600ms之后。(4)fMRI实验结果中,图-词的名字匹配在楔前叶、额区和枕区的激活比不匹配和类别匹配少,表现出重复抑制。从三种匹配条件之间的差异来看,不匹配和名字匹配相比,在楔前叶的激活显著;而不匹配与类别匹配相比,在额区、枕区和内侧颞区都有激活。相比其它两种条件,类别匹配在额区、内侧颞区和顶区存在较多激活。基于以上研究结果,我们从行为和大脑认知神经加工的时间和空间机制几个层面对不同形式不同内容的匹配加工如何影响对词语的情景提取问题进行了深入的讨论和分析,得出以下结论:(1)工作记忆匹配加工编码与情景记忆提取存在着非对称性,提取是对编码信息的重复激活或印记激活,但不是对编码的简单复原,在长时情景提取中尤为如此。(2)工作记忆加工的名字匹配和类别匹配对情景提取影响不同。名字匹配加工的材料形式影响情景提取,可能存在易化或抑制现象;而语义类别匹配加工与不匹配加工相比不存在易化或抑制效应。(3)工作记忆图和词的跨形式和同形式匹配加工可能共用相同的语义概念表征系统,而在具体加工过程中存在形式特异化。(4)工作记忆图和词的跨形式和同形式匹配加工对情景提取的影响不同,其关键因素可能在于P300成分。(5)楔前叶可能具有语义匹配加工的功能。本研究从短时工作记忆延迟匹配加工角度,探讨了编码与提取的关系以及工作记忆和情景记忆的关系,进一步证实提取不是对编码的简单复原,丰富了以往对编码与提取及工作记忆和情景记忆关系的脑机制研究,同时也为重复抑制理论提供了支持。本研究结果可为我们的学习和记忆以及其他现象的解释提供一定的依据。更多还原

【Abstract】 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.更多还原