HERA模型与来源记忆老化

以考查来源记忆老化与来源记忆过程中额叶激活模式的关系为目的.采用行为测验和fMRI(功能磁共振成像)技术,以位置记忆为任务,对15位年轻人和13位老年人在来源记忆过程中的额叶激活模式进行比较.行为结果表明位置记忆存在显著年龄差异.脑成像结果表明:1)编码阶段在2个难度条件下,老年人和年轻人的额叶激活都表现出左侧优势;提取阶段在2个难度条件下,老年人和年轻人的激活模式都没有表现出单侧化倾向.HERA模型不具有跨年龄和任务的普遍性;2)在低难度任务中,编码和提取阶段老年人与年轻人的额叶激活模式基本相同,老年人的激活面积稍大;在高难度任务中,编码阶段除额下回老年人比年轻人激活稍多外,年轻人的激活脑区明显多于老年人.提取阶段,老年人和年轻人的激活的脑区基本没有差异.来源记忆老化与加工过程的关系还需要进一步探讨.     

浅析地理知识在中学历史教学中的作用

在初中历史教学过程中,运用地理知识可以阐明缘由,让学生了解影响历史事件发生、演变的各种因素;图文对照,可以增强学生的记忆和理解;史地对比,可以避免知识混淆;还可以用地理知识揭示历史规律等。但要把握"用"的尺度,且不可喧宾夺主。     

基于fMRI与MEG数据融合的大脑语言处理的激活分析

本文对同一组被试进行相同的语言实验任务,同时采集被试的功能磁共振图像数据和脑磁数据,通过对两种神经成像技术进行融合,弥补两种方法在分辨率上各自存在的不足.本实验采用fMRI-MEG数据融合的方法对采集的数据进行处理,得到了具有高时空分辨率的信号,从而能够更加精确地对大脑在处理语言任务时的激活区域进行定位.通过激活区域分析,更好地理解大脑在处理语言任务时的工作机制.由本实验可以推断大脑在处理语言任务的过程是:听觉冲动首先传导到听觉区域并产生听觉,同时韦尼克区会强烈激活,随后神经传导到运动性语言中枢控制所有与运动有关的皮质以做出相应的反应.     

参与中文配对词语联想学习记忆的脑区和神经机制——脑功能磁共振的研究

通过脑功能磁共振技术,研究健康人参与语言的词语配对联想学习记忆任务的脑区和神经机制。对16名右利手健康志愿者进行一项词语配对联想学习记忆任务作业的同时,进行脑功能磁共振扫描。实验采用组块设计,实验任务（包括记忆编码相和记忆提取相）与对照任务（共两个相）交替进行;数据采用SPM99软件进行数据分析和脑功能区定位。结果表明：左侧额叶,特别是左侧额叶的额中下回和枕叶的18,19区在词语联想学习记忆的编码阶段中起重要作用;而左侧顶上小叶、缘上回和角回则在进行记忆提取阶段起重要作用;左侧纹状体边缘区参与了人脑词语联想学习记忆作业的编码阶段。揭示了人大脑完成语言联想学习记忆任务时,除额、顶、枕和颞叶的皮层结构参与外,还新发现有皮层下结构如纹状体参与了词语联想学习记忆。在配对词语的编码和提取阶段,激活的脑区有所变化,显示了这两个语言阶段的神经活动变化机制。     

科学家研究揭示记忆再巩固机制

<正>复旦大学脑科学研究院马兰研究组发现,一种记忆形成后,通过回忆可激活脑内的β抑制因子神经通路,使记忆得以"再巩固",而不是像以往经典理论所认为的,是激活G蛋白通路后导致记忆"再巩固"。专家认为,该发现有助于阐明记忆长期存储的分子机制,并对新靶向药物研发有重要意义。     

自传体记忆研究的若干新进展

总结了自传体记忆研究中新近出现的功能研究取向以及自传体记忆脑机制的神经心理学研究和脑成像研究结果。功能取向的研究表明,自传体记忆具有自我、社会和指导这3类主要功能。神经心理学和脑成像研究发现自传体记忆主要定位于颞叶与海马,但这2方面研究的结果之间却存在着很大的不一致：以脑损伤病人进行的神经心理学研究发现自传体记忆主要表现为右侧颞叶与海马的功能,而对正常人的脑成像研究却表明提取自传体记忆事件时主要的激活部位是左侧颞叶与海马。目前尚无关于这种不一致现象的评论与解释,由于自传体记忆的脑成像研究数量较少且结论并不一致,在进行更多的脑成像研究之后再来比较神经心理学与脑成像的研究结果可能更为合适。     

创伤事件的闯入记忆的理论与研究

闯入记忆是创伤事件发生后最常被报告的现象,具有反复、不可控制、易激活等特点,认知加工理论和警报信号理论可以用来解释闯人记忆的产生,而它的痛苦性、现时性和缺乏联系性能有效地预测创伤后应激障碍;影响闯入记忆的因素主要有认知评价和应对策略,频繁的闯入会降低人们的生活质量,而对闯入记忆的干预如想象再现,社会支持、表达性笔记等能有效地降低闯入记忆.     

杏仁核参与情绪记忆的脑功能成像研究述评

脑功能成像技术近年来已应用于情绪记忆的研究,相关的研究结果扩展了依据动物实验所得到的有关结论.作者主要对近年来情绪记忆的编码和提取阶段的脑成像研究进行了综述.研究表明,杏仁核在情绪记忆中的作用不仅局限在巩固阶段,它的作用在编码过程的初期已显示出来,并参与记忆的提取过程.脑区相关和联结模型强调了杏仁核与内侧颞叶等之间的交互作用.已有的研究还表明,刺激类型是影响情绪记忆的重要因素之一.杏仁核还参与对情绪的刺激类型、情绪记忆的生动感和主观性的加工.在今后的研究中将多种神经科学的技术相结合会更深入地揭示情绪记忆的脑机制.     

边缘刺激条件下错误记忆无意识机制的探索研究

文章援用错误记忆中经典的DRM范式,在实验中,要求被试对呈现的颜色刺激作辨别反应时任务.同时将DRM词单中的单词作为边缘刺激随机呈现.随后意外地要求被试对边缘处单词进行再认.结果证明了被试在作反应时任务时,对边缘刺激产生无意识知觉同时进行了自动的无意识语义加工,这种对单词的无意识语义加工体现在随后的再认任务中,较多地再认出了与词单高度相关但未呈现的关键项.发生了错误记忆.     

基因表达也能超声成像

<正>超声波可以帮助检查心脏是否缺损,还能让准爸爸准妈妈提前和腹中的胎儿"见面"。而一项于2019年9月26日发表在Science上的研究向我们展示了超声波的最新功能——在动物体内检测特定基因是否被激活。细胞不断地"打开"和"关闭"基因的表达开关。为了观察这一活动,研究人员可以对细胞进行基因修饰,使特定基因(报道基因)在被激活时产生发     

Orientation to learning context modulates retrieval processing for unrecognized words

Explicit memory errors may occur when individuals fail to retrieve information about items previously studied (item memory) or about the learning context (source memory). We examined electrophysiological measures during recognition failure in order to determine the influence of retrieval orientation for item versus source information. Recognition failure was associated with brain potentials distinct from those associated with success. Furthermore, source-memory failures were associated with earlier-onset brain potentials with a more anterior distribution compared to item-memory failures. Neurocognitive processing was thus modulated by retrieval orientation so as to differentially influence neural correlates of successful versus unsuccessful retrieval.     

Neural organization for the long-term memory of paired associates

Most of our long-term memories of episodes or objects are organized so that we can retrieve them by association. Clinical neuropsychologists assess human memory by the paired-associate learning test, in which a series of paired words or figures is presented and the subject is then asked to retrieve the other pair member associated with each cue. Patients with lesions of the temporal lobe show marked impairment in this test. In our study, we trained monkeys in a pair-association task using a set of computer-generated paired patterns. We found two types of task-related neurons in the anterior temporal cortex. One type selectively responded to both pictures of the paired associates. The other type, which had the strongest response to one picture during the cue presentation, exhibited increasing activity during the delay period when the associate of that picture was used as a cue. These results provide new evidence that single neurons acquire selectivity for visual patterns through associative learning. They also indicate neural mechanisms for storage and retrieval in the long-term memory of paired associates.     

随机延时Hodgkin-Huxley神经网络的同步与联想记忆

基于神经系统微观生理结构,给出具有空间分布随机延时的神经元间耦合,而这种随机延时描述峰电位从突触前神经元到突触后神经元在轴突上传播所需要的时间．记忆由时空发放的神经元集群表达．通过加入并改变噪声的强度,研究了噪声对Hodgkin—Huxley（HH）神经元网络系统联想记忆的作用,在噪声涨落的作用下,系统取得了对不完整输入的记忆恢复,得到与熟知的随机共振完全一致的结果．     

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.     

编码和提取过程中日语汉字和假名的差异比较

 为了解明中国人日语学习者记忆日语汉字和假名词汇时所关联的脑神经机制,本研究比较了日语汉字和假名在编码和提取过程中所诱发的ERP成分的差异。在学习阶段,汉字和假名条件的各ERPs成分的波幅-潜时之间存在着显著性差异,汉字条件的P300和N400的波幅都显著大于假名条件,潜时也比假名条件出现得更早,这些结果说明汉字的编码加工比假名更快更深刻。在提取阶段,相对于旧假名,旧汉字诱发了低波幅·短持续时间的FN400和高波幅·短持续时间的LPC(晚期阳性慢波)。这些结果显示了旧汉字的熟悉性效果更大,旧汉字能被更快更好地回忆起来。而且它们的编码和提取具有明显的半球优异性特征,说明了与汉字和假名的记忆相关联的脑神经机制不同。本文认为,由于假名的记忆加工比汉字复杂,增加了假名的记忆负荷,导致记忆成绩比汉字差,解明汉字和假名的记忆特征对日语学习具有重要的指导作用。     

Glutamate-receptor-mediated encoding and retrieval of paired-associate learning

Paired-associate learning is often used to examine episodic memory in humans. Animal models include the recall of food-cache locations by scrub jays and sequential memory. Here we report a model in which rats encode, during successive sample trials, two paired associates (flavours of food and their spatial locations) and display better-than-chance recall of one item when cued by the other. In a first study, pairings of a particular foodstuff and its location were never repeated, so ensuring unique 'what-where' attributes. Blocking N-methyl-d-aspartate receptors in the hippocampus--crucial for the induction of certain forms of activity-dependent synaptic plasticity--impaired memory encoding but had no effect on recall. Inactivating hippocampal neural activity by blocking alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors impaired both encoding and recall. In a second study, two paired associates were trained repeatedly over 8 weeks in new pairs, but blocking of hippocampal AMPA receptors did not affect their recall. Thus we conclude that unique what-where paired associates depend on encoding and retrieval within a hippocampal memory space, with consolidation of the memory traces representing repeated paired associates in circuits elsewhere.     

Disruption of neurotransmission in Drosophila mushroom body blocks retrieval but not acquisition of memory

Surgical, pharmacological and genetic lesion studies have revealed distinct anatomical sites involved with different forms of learning. Studies of patients with localized brain damage and work in rodent model systems, for example, have shown that the hippocampal formation participates in acquisition of declarative tasks but is not the site of their long-term storage. Such lesions are usually irreversible, however, which has limited their use for dissecting the temporal processes of acquisition, storage and retrieval of memories. Studies in bees and flies have similarly revealed a distinct anatomical region of the insect brain, the mushroom body, that is involved specifically in olfactory associative learning. We have used a temperature-sensitive dynamin transgene, which disrupts synaptic transmission reversibly and on the time-scale of minutes, to investigate the temporal requirements for ongoing neural activity during memory formation. Here we show that synaptic transmission from mushroom body neurons is required during memory retrieval but not during acquisition or storage. We propose that the hebbian processes underlying olfactory associative learning reside in mushroom body dendrites or upstream of the mushroom body and that the resulting alterations in synaptic strength modulate mushroom body output during memory retrieval.     

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.     

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.