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。     

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.     

睡眠剥夺对面孔情绪加工的影响——认知神经科学的视角

面部表情是社会互动和情绪感染的重要形式,准确的面部情绪加工有助于做出合适的社会行为.睡眠缺乏会影响面孔情绪加工的不同方面,损伤面孔情绪分类和模糊情绪评级,并减弱记忆的巩固效果.以往研究通过不同类型的剥夺操作,为整夜睡眠、快速眼动(REM)睡眠和非快速眼动(NREM)睡眠在面孔情绪加工中的作用提供了依据.综合已有证据,面孔情绪加工异常可能是REM阶段特异性依赖的,体现在杏仁核、前额叶、脑岛及前扣带等脑区的皮层活动及睡眠阶段γ和θ等脑电活动.应加强睡眠阶段或组合在面孔情绪加工中的机制探讨,有望未来基于面孔情绪加工,更好地实现对睡眠相关疾病的诊断及治疗效果的预测.     

大脑皮层对飞机飞越噪声的认知机制

为了研究人类大脑皮层对飞机飞越噪声的表达机制,采用功能磁共振成像(fMRI)技术,选择25例正常健康受试者,观察在飞机飞越噪声刺激时大脑功能区的激活情况,通过对数据进行统计学处理以及脑功能区定位,结果表明:25例受试者在飞机飞越噪声刺激时大脑显著激活了视觉联合皮层、前额叶皮层、初级运动皮层以及与认知记忆相关的脑区等.飞机飞越噪声刺激下,大脑皮层听觉区域不仅参与了听觉处理,可能还涉及消极情绪、认知、注意、记忆等区域反应.     

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。     

情绪的神经生物研究

情绪的研究一直是一个重要领域,同时由于情绪的复杂性,使得情绪的研究具有相当的难度。近年来脑成像技术（fMRIPET）和事件相关电位（ERP）等技术的发展,推动了情绪与认知的神经生理基础的研究。本文从情绪的评定标准、被试的选取、实验材料的编制以及研究技术等方面介绍了情绪神经生物基础研究的基本方法;叙述了情绪刺激加工中情绪活动中,大脑半球的偏侧化效应,脑成像研究中发现正负效价情绪的加工由大量重叠神经通道负责,而不同性质的面部表情由不同的神经通道负责。     

非编码RNA与心肌重构

非编码RNA(non-coding RNAs, ncRNAs) 是一类不编码蛋白质的RNA 分子. 相关研究表明, ncRNAs 不仅参与细胞的增殖、凋亡、分化、代谢等生理过程, 还参与疾病的病理过程. 心肌重构(myocardial remodeling)是多种心血管疾病最主要的病理基础. 已有多项研究表明, 心肌重构的发生发展与ncRNAs 的调控息息相关, 近年来针对ncRNAs 在心脏疾病方面的研究也得到了迅猛发展. 对ncRNAs 包括微小RNA(microRNAs, miRNAs)、长链非编码RNA(long non-coding RNAs, lncRNAs)和环形RNA(circular RNAs, circRNAs) 与心肌重构的最新研究进展以及作用机制进行介绍, 旨在寻找新的心脏疾病治疗靶点.     

情绪动机对记忆窄化影响的研究综述

情绪性事件的记忆往往是最生动也是最持久的。然而,人们对于这些记忆通常都是有选择性的。人们对于情绪事件相关的中心信息记忆情况比边缘细节要好。最近的研究表明,与离散情绪相联系的目标或者是动机决定认知过程的宽度。具体来说:在目标得到或者失去之前所体验到的情绪会导致记忆窄化;在目标得到或者失去之后所体验到的情绪则会拓宽记忆中信息编码的范围。本综述在梳理了记忆窄化的理论和研究的基础上,阐述情绪动机影响记忆窄化的相关研究进展,并对未来研究方向提出了几点展望。     

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。     

杏仁核在疼痛及疼痛引起的情感和认知障碍中的作用

疼痛是一种不愉快的感觉和情绪体验, 伴随有强烈的负性情绪(如厌恶、恐惧、焦虑等)。 杏仁核作为边缘系统的皮质下中枢,在情绪反应中具有重要作用。我们的研究表明杏仁核在疼痛调制,特别是疼痛情绪反应中起关键作用。本文综述了杏仁核在疼痛及疼痛引起的焦虑行为和认知功能障碍中的作用。     

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.     

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。     

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.     

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。     

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.     

Picture encoding and retrieval： An event-related potentials study

A study-test paradigm was used to investigate the Dm (Differential memory) effect and the old/new effect of pictures. The participants were asked to judge whether the pictures were previously studied or not when they were presented with a series of pictures during the test phase. The event-related potentials (ERPs) were recorded during encoding and retrieval phases. The results showed that (1)during 400-700 ms of encoding, the remembered old pictures elicited more positive waveforms than the forgotten old pictures at frontal and central areas; (2) during 500-600 ms of retrieval, the correctly judged old pictures elicited more positive waveforms than the correctly judged new pictures at medial-midline in both hemispheres; (3) the duration of Dm effect was longer than that of old/new effect for picture. The present results suggest that the Dm effect of pictures is different from that of words and faces in spatial and temporal distributions. The neural mechanisms of picture encoding and picture retrieval are also different, which indicates that retrieval is not the simple recovery of encoding.     

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.     

Learning-related feedforward inhibitory connectivity growth required for memory precision

In the adult brain, new synapses are formed and pre-existing ones are lost, but the function of this structural plasticity has remained unclear. Learning of new skills is correlated with formation of new synapses. These may directly encode new memories, but they may also have more general roles in memory encoding and retrieval processes. Here we investigated how mossy fibre terminal complexes at the entry of hippocampal and cerebellar circuits rearrange upon learning in mice, and what is the functional role of the rearrangements. We show that one-trial and incremental learning lead to robust, circuit-specific, long-lasting and reversible increases in the numbers of filopodial synapses onto fast-spiking interneurons that trigger feedforward inhibition. The increase in feedforward inhibition connectivity involved a majority of the presynaptic terminals, restricted the numbers of c-Fos-expressing postsynaptic neurons at memory retrieval, and correlated temporally with the quality of the memory. We then show that for contextual fear conditioning and Morris water maze learning, increased feedforward inhibition connectivity by hippocampal mossy fibres has a critical role for the precision of the memory and the learned behaviour. In the absence of mossy fibre long-term potentiation in Rab3a(-/-) mice, c-Fos ensemble reorganization and feedforward inhibition growth were both absent in CA3 upon learning, and the memory was imprecise. By contrast, in the absence of adducin 2 (Add2; also known as β-adducin) c-Fos reorganization was normal, but feedforward inhibition growth was abolished. In parallel, c-Fos ensembles in CA3 were greatly enlarged, and the memory was imprecise. Feedforward inhibition growth and memory precision were both rescued by re-expression of Add2 specifically in hippocampal mossy fibres. These results establish a causal relationship between learning-related increases in the numbers of defined synapses and the precision of learning and memory in the adult. The results further relate plasticity and feedforward inhibition growth at hippocampal mossy fibres to the precision of hippocampus-dependent memories.     

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.