Neural correlation of item recognition and voice source retrieval

An experiment was conducted using event-related potentials to investigate the old/new effects of the item recognition and the voice source retrieval tasks on drawing. The results indicated that (1) the old/new effect for the voice source retrieval task was much wider than that of the item recognition task; (2) the distributive characteristics of the voice source memory effect were different from those in previous studies; (3) the old/new effects for target and non-target-old drawings were similar. These results demonstrated that the voice source retrieval task is more difficult than the item recognition task for drawing, which supports the dual-process model. The experimental material and the source characteristic regulate the spatial and temporal distributions of the old/new effect for the voice source retrieval task together.     

Neural correlation of item recognition and voice source retrieval

An experiment was conducted using event-related potentials to investigate the old/new effects of the item recognition and the voice source retrieval tasks on drawing. The results indicated that (1) the old/new effect for the voice source retrieval task was much wider than that of the item recognition task; (2) the distributive characteristics of the voice source memory effect were different from those in previous studies; (3) the old/new effects for target and non-target-old drawings were similar. These results demonstrated that the voice source retrieval task is more difficult than the item recognition task for drawing, which supports the dual-process model. The experimental material and the source characteristic regulate the spatial and temporal distributions of the old/new effect for the voice source retrieval task together.     

What can false memory tell us about memory impairments in Alzheimer’s disease?

The range of memory impairments associated with Alzheimer’s disease (AD) has been a focus for psychological and clinical re-searchers for many years. In addition to investigations of AD patients’ veridical memory using traditional recognition memory tasks, a number of recent studies have focused on false memories to reveal the underlying causes of memory impairment in AD. Studies comparing illusory memories between AD patients and healthy older people have revealed various differences in memory deficits between the development of AD and the typical aging processes. Here, we review 3 types of memory illusions tested in AD patients: associative memory illusions, fluency-based false memories and source memory errors. By comparing AD patients with healthy older adults, we sought to analyze the mechanisms underlying AD-related memory impairments at different stages of memory processing, including encoding, retrieval and monitoring. This comparison revealed that AD patients exhibit an impaired ability to establish and utilize gist representations at the encoding stage and impairments in processing on the basis of familiarity and recollection at the retrieval stage. Consequently, patients with AD have access to less information when making memory judgments. As a result, they become more susceptible to the effects of item fluency, which can be manipulated during the retrieval stage. Furthermore, with impaired source memory monitoring abilities, the capacity of AD patients to suppress memory illusions is compromised. Based on these findings, we propose that the study of false memories constitute a critical tool for elucidating the memory impairments involved in AD. Further explorations of these memory impairments will have practical significance for the diagnosis and treatment of AD in the future.     

记忆编码和提取中的神经激活模式再现?

情景记忆使得人们可以在头脑中生动地经历已经发生过的事件,然而支持这一过程的神经机制还没有得到很好地理解.本文针对近年来基于神经激活模式分析的研究对"神经激活模式再现"的假说进行了整合分析,提供了重要的支持性证据.这些研究发现,成功地提取伴随着编码时神经激活模式的再现,且再现的发生先于行为判断出现;除此以外,神经激活重现可以在重复学习过程中发生,或者由相似的学习材料引发,且这种再现程度与随后的记忆效果相关;此外,神经激活模式再现还可以在睡眠和休息条件下自发地产生,促进随后的记忆成绩.在此基础之上,本研究还进一步考察了神经激活模式的本质特征,探讨了内侧颞叶和额顶皮层等重要脑区在再现过程中的作用,并对神经激活模式再现的研究方向进行了展望.     

Parietal cortex contributions to information granules following memory consolidation

Previous studies have focused on changes in cerebral cortex activity accompanying memory formation and consolidation. Although the role of the parietal cortex in memory retrieval is well established, it is not well understood how parietal cortex memory con-solidation for mathematical rules is related to granularity of stored information (i.e., degree of detail or precision). Changes in parietal cortex activity associated with memory consolidation were analyzed using the Ebbinghaus paradigm and functional magnetic resonance imaging (fMRI). Over the course of 1 week, participants learned Boolean arithmetic tasks involving stimulus-response mapping rules containing either low- or high-granularity information. FMRI images were collected on day 1 (i.e., low-granularity condition) and day 7 (i.e., high-granularity condition). The present data suggested that with practice, stored information was converted from a low-granularity to a high-granularity form. By following rule learning, it was hypothesized that the process of consolidation would involve an increased degree of rule representation granularity. Evidence for this process was reflected in parietal cortex activity. This finding was consistent with the hypothesis that mnemonic reconstruction in the parietal cortex is required for memory consolidation, and results suggested that information granules are formed during memory consolidation. The present results could increase the understanding of the relationship between memory consolidation and information granularity.     

Interactions between working memory and selective attention

Event-related potential (ERP) was used to examine the interactions between working memory and se- lective attention. We combined two unrelated tasks, one requiring working memory and the other se- lective attention, which were performed by some undergraduates. The ERP results revealed that both congruent and incongruent stimuli in the selective attention task evoked an N400 component, reaching the peak point at around 500 ms. The N400 evoked by incongruent stimuli was more negative than that of congruent, which indicated the difference of semantic N400. Furthermore, working memory load had a significant influence on the N400 evoked by selective attention task in parietal region. And working memory load showed difference in the ERPs of working memory retrieval in central and parietal regions. The ERPs of probe under high working memory load were more positive from 350 to 550 ms post-stimulus; however, stimulus type of selective attention had no influence on working memory re- trieval. The present study shows that working memory does not play a major role in the selective at- tention, especially in ignoring distracter, but it influences the performance of the selective attention as the background. The congruency of target and distracter in the selective attention task does not influ- ence the working memory retrieval.     

中国期刊全文数据库引文检索方法和效果探析

中国期刊全文数据库（简称CJFD）引文检索功能之强大在国内的全文数据库中无以伦比,但也存在一些需要改进的地方：检索项缺少被引机构检索字段,故不能以被引机构进行入口检索或限制检索范围;检索结果缺少统计分析功能,致使引文检索结果不易甄别和统计．建议：（1）引文著录增加引文机构项,以便提供检索点;（2）CJFD检索项增加被引机构检索字段,以使引文检索更加便捷高效;（3）增加引文统计分析功能,节省检索者分析、筛选、甄别信息的时间;（4）完善检索结果显示,检索结果既能反映引用文献信息,又能反映被引文献信息．     

工作记忆编码腹侧海马和内侧前额叶皮层局部场电位信号的相位同步分析

研究比较大鼠在静息状态下和工作记忆编码阶段腹侧海马和内侧前额叶皮层局部场电位相位同步的变化,分析相位在工作记忆任务相关信息处理中的作用机制。研究数据为6只SD大鼠静息状态和执行Y迷宫空间工作记忆任务时采集的腹侧海马和内侧前额叶皮层的局部场电位信号,计算两个脑区局部场电位信号之间的加权相位滞后指数值。研究结果表明,与静息状态相比,在工作记忆编码阶段,腹侧海马和内侧前额叶皮层之间的相位同步性在theta频段选择性地显著增加。腹侧海马和内侧前额叶皮层theta频段的相位同步是工作记忆编码阶段任务信息处理的一个作用机制。     

Effects of encoding and retrieval on the mechanism of item + context binding

To investigate the neural mechanism of semantic representation and color context binding, we used electroencephalograph time frequency and coherence analyses to reveal local and long-range functional coupling in the encoding and retrieval phases of episodic memory. Fifteen undergraduates participated in the experiment and middle-frequency double-character Chinese words were used as stimuli in two types of study-test tasks (context recall and context recognition tests). Significant differences between item+context and item in the encoding phase were observed at the electrodes in the frontal region at 600–800 ms by time frequency analysis. Further differences were observed at 800 ms by independent component analysis: the frontal component and the coherent component of the triangle phase locking structure among the prefrontal, right parietal and left parietal-occipital regions. In the retrieval phase, differences between item+context and item were found on the electrodes at the central parietal and parietal-occipital regions at 400 ms by time frequency analysis, on the parietal-occipital component at 800 ms by independent component analysis and on the coherence component of the anterior right hemisphere and parietal-occipital regions at 1400 ms. In conclusion, the different effects of encoding and retrieval processing on ‘binding’ are reflected by the differing extents that brain regions engaged in cognitive operations. In the retrieval phase in particular, activities of the parietal-occipital region were specifically associated with ‘binding’, and coherence between frontal and temporal-parietal regions is a common brain activity in episodic memory.     

考虑岩石交界面方向效应的巴西劈裂试验研究

为了研究硬岩与软岩交界面方向对其破坏形式的影响,对含岩石-水泥砂浆(代替软岩)交界面的组合试样进行了多组加载角度的巴西劈裂试验,获得了不同交界面方向的组合试样的"抗拉"强度,并利用颗粒流程序PFC2D研究了交界面的破坏机理.计算得到的"抗拉"强度随交界面与加载方向夹角的增大而增大.当交界面平行于加载方向时,沿交界面发生劈裂破坏,计算得到的"抗拉"强度可认为是交界面的抗拉强度;当交界面与加载方向不平行时,发生更为复杂的拉―剪复合破坏.此外,为了进一步分析交界面的抗拉强度对破坏形式的影响,采用提高水泥用量和增大交界面粗糙度两种方法增加交界面的抗拉强度,并进行了一系列试验.试验得到了含交界面的巴西劈裂试验的典型破坏模式分布图,对更好地理解硬岩与软岩交界面的破坏形式具有指导意义.     

分配注意对短时记忆编码和提取的影响

以大学生为被试,采用分配注意范式探讨了短时记忆编码和提取所需的注意资源。研究发现：与集中注意相比,编码阶段进行第二作业导致记忆成绩显著降低,而提取阶段进行第二作业则对记忆成绩没有影响。自由回忆和顺序回忆的结果一致。本研究表明,短时记忆编码是需要较多注意资源的控制加工,而短时记忆提取则是相对无需注意资源的自动加工。这与当前关于长时记忆的研究结果类似,而与早期以第二作业成绩为测量指标的短时记忆研究结果有所不同。     

基于粒子群的大量信息模糊检索

为了改善随着信息量增加信息检索效率急剧降低的情况,将改进的粒子群优化算法引入信息检索中,通过粒子群算法迭代检索,使关键检索字在大量信息点上模糊匹配,在迭代终止时检索出匹配度最高的信息项。对100万到2亿条信息量的信息进行检索实验,检索时间1．7s左右,匹配度高于97％。该方法检索速度快、稳定、匹配度高且鲁棒性强。     

Material differences of auditory source retrieval: Evidence from event-related potential studies

Two event-related potential experiments were conducted to investigate the temporal and the spatial distributions of the old/new effects for the item recognition task and the auditory source retrieval task using picture and Chinese character as stimuli respectively. Stimuli were presented on the center of the screen with their names read out either by female or by male voice simultaneously during the study phase and then two testa were performed separately. One test task was to differentiate the old items from the new ones, and the other task was to judge the items read out by a certain voice during the study phase as targets and other ones as non-targets. The results showed that the old/new effect of the auditory source retrieval task was more sustained over time than that of the item recognition task in both experiments, and the spatial distribution of the former effect was wider than that of the latter one. Both experiments recorded reliable old/new effect over the prefrontal cortex during the source retrieval task. However, there existed some differences of the old/new effect for the auditory source retrieval task between picture and Chinese character, and LORETA source analysis indicated that the differences might be rooted in the temporal lobe. These findings demonstrate that the relevancy of the old/new effects between the item recognition task and the auditory source retrieval task supports the dual-process model; the spatial and the temporal distributions of the old/new effect elicited by the auditory source retrieval task are regulated by both the feature of the experimental material and the perceptual attribute of the voice.     

Neural encoding of individual words and faces by the human hippocampus and amygdala

Patients with lesions in the medial temporal lobe (MTL) of the brain, which includes the hippocampus, amygdala and parahippocampal gyrus, are severely impaired in their ability to remember and recognize words or faces which they saw only a short time ago. These lesions also prevent the effect of word repetition on cortical event-related potentials that are associated with these tasks. We have been able to study the response of individual neurons in the human medial temporal lobe to such delayed recognition tasks in epileptic patients undergoing neurosurgery. We found that some MTL neurons preferentially fired on sight of one particular word from a set of ten words used in a memory task, and others fired in response to one particular face. This stimulus-specific firing was maximal during the time that the neocortical event potentials are most sensitive to stimulus repetition, suggesting that the MTL contributes specific information to the cortex during the retrieval of recent memories.     

ERP dissociation and connection between implicit and explicit memory

ERP dissociations between implicit and explicit memory have been confirmed by a large amount of evidence in theories of human memory. However, similarities between the two forms of memory have scarcely been studied. A possibility is that while implicit memory and explicit memory have independ- ent components, they might additionally have shared components. To explore this question, an ERP experiment was conducted with a study-to-test paradigm, in which participants performed a "shallow" (color) study task or a "deep" (pleasant) study task, followed by either a lexical decision (implicit) test (Section 1) or a recognition (explicit) test (Section 2). An interference task was performed concurrently with either the encoding or the retrieval phase of the memory task for encoding interference condition or retrieval interference condition. We compared ERP signatures of implicit and explicit memory as a function of depth of processing or interference. Under the action of the same variables, 300―500 ms old/new ERP effects of implicit and explicit memory showed the same trend. These effects maybe all link with a perceptual representational system. 500―700 ms old/new ERP effects of the two memories were dissociated. They may probably reflect voluntary and involuntary recollection respectively. These results suggested that implicit and explicit memories are not completely independent of each other, but have both independent and shared components.     

实现记忆检索和回忆中漫游的一种计算AM模型（论文撤稿）

为了捕捉自传体记忆，提出了一种针对自传体记忆的计算AM模型.模型为3层网络结构.底层由5W1H构成的特定事件知识进行编码，提供检索线索；中间层通过关联特定事件知识对事件进行编码；顶层通过关联相关事件对事件集进行编码.按照自下而上的记忆搜索过程，AM模型可以分别在中间层和顶层识别相应的事件和事件集，同时，还能通过规则记忆检索过程模仿人在回忆中漫游的现象.基于一组数据集的实验结果表明，模型不仅具有鲁棒的、灵活的记忆检索，而且相较于普遍采用的基于关键字的查询方法记忆检索模型，对含噪记忆检索线索有更好的响应性能，还能够模仿回忆中的漫游现象.     

心理时间之旅——情景记忆的独特性

情景记忆是由自我、自我觉知和主观时间组成的惟一指向过去的认知神经系统,它使心理时间旅行成为可能。与其他记忆系统相比,情景记忆的独特性不仅表现在提取信息时伴随着自我觉知,指向过去,而且情景记忆还有其独特的脑定位,许多研究支持情景记忆的编码主要与大脑的左半球有关,提取主要与右半球有关。由于情景记忆与自我、意识有密切的关系,情景记忆的研究必将极大地推动记忆与意识的研究。     

实现记忆检索和回忆中漫游的一种计算AM模型（论文撤稿）

为了捕捉自传体记忆,提出了一种针对自传体记忆的计算AM模型.模型为3层网络结构.底层由5W1H构成的特定事件知识进行编码,提供检索线索;中间层通过关联特定事件知识对事件进行编码;顶层通过关联相关事件对事件集进行编码.按照自下而上的记忆搜索过程,AM模型可以分别在中间层和顶层识别相应的事件和事件集,同时,还能通过规则记忆检索过程模仿人在回忆中漫游的现象.基于一组数据集的实验结果表明,模型不仅具有鲁棒的、灵活的记忆检索,而且相较于普遍采用的基于关键字的查询方法记忆检索模型,对含噪记忆检索线索有更好的响应性能,还能够模仿回忆中的漫游现象.     

Relationship between prospective memory and vigilance: Evidence from ERP

Event-related potentials (ERPs) were used in this study to investigate the neural correlates of prospective memory (PM) and vigilance. Twenty college or graduate students participated in this study. They were administered a PM and a vigilance task and physiological data were collected at the same time. Behavioral results showed that the RT associated with PM cues was longer than those associated with vigilance targets. ERP results showed that PM cues and vigilance targets did not show significant difference in the N2 but PM cues evoked greater N300 than vigilance targets, and vigilance targets evoked greater parietal positivity/P3 than PM cues, suggesting vigilance and PM have similar but also distinctive neural basis.     

Differences of relevance in implicit and explicit memory tests: An ERP study

An ERP study was conducted to explore the differences between other-relevant words and possessor-relevant words in implicit and explicit memory tests. The results show that other-relevant words are associated with a more negative ERP than possessor-relevant words during 300--900 ms whether in the implicit or the explicit memory tests. The N400 effect is also found in semantic processing of social materials. There is an ERP dissociation of retrieval formats between the implicit and the explicit memory tests during 700--900 ms, namely, there is no difference between other-relevant words and possessor-relevant words in the implicit memory while there is a significant difference between them in the explicit memory. Observed through Curry 6.0, the analysis of neural sources for other-relevant words and possessor-relevant words indicates that they have different locations. At 400 ms, activity is found in the left precuneus during possessor-relevant words processing. Both the right and the left precuneus are activated during other-relevant words processing. However, at 600 ms their location is both in the left precuneus. In a word, our results show that there exists a cognitive difference between other-relevant words and possessor-relevant words, and other-relevant words closely related to the percipient himself/herself are strongly responded to, which reflects that there is a bigger attention bias to the stimuli concerning the percipient himself/herself than to processor-relevant words.