Episodic memory effects of gamma frequency precuneus transcranial magnetic stimulation in Alzheimer's disease: A randomized multiple baseline study

Episodic memory decline is the prominent neuropsychological feature of typical Alzheimer's Disease (AD), for which current treatments have a limited clinical response. Recently, gamma entrainment therapy has been used as a non-invasive treatment in AD, providing evidence that it may have the potential to alleviate brain pathology and improve cognitive function in AD patients. At the same time, the precuneus (PC) has been recognized as a key area involved in AD related memory deficits and as a key node of the Default Mode Network. This study aimed to investigate the effectiveness of a 40 Hz Transcranial Magnetic Stimulation (TMS) intervention, delivered bilaterally to the precuneus for 10 days, in improving the patients' episodic memory performance. Secondary outcome variables investigated included general cognitive function, semantic and spatial memory, as well as attention and executive function. A concurrent multiple baseline design across five cases was employed. Four patients completed the study. Visual analysis combined with effect size indices were used to evaluate changes across phases. An increase in the average level of immediate recalled words was observed in three out of four patients. Effect size indices indicated significant improvement of attention skills in two patients. No treatment effect was observed for semantic and visual memory, or for executive function. An immediate treatment effect was observed in all patients' general cognitive function as assessed with the Alzheimer's Disease Assessment Scale (mean reduction of 5 points), which was maintained and improved further three months post-treatment. The neuropsychological evaluations indicated improved performance three months post-treatment in immediate and delayed recall, attention, phonological verbal fluency, anxiety, and neuropsychiatric symptoms. This study provides preliminary evidence for the efficacy of a novel non-pharmacological treatment using gamma-band TMS in addressing cognitive dysfunction in AD.     

Changes in Children's Episodic Narratives Through Long-Term Repeated Recall: Longitudinal Case Studies1

This study aimed to investigate whether a child's narrative of a particular past episode would change in repeated reporting over the long term, and if so, how it would change. To answer these questions, I conducted longitudinal case studies of episodic reports by children every 2–6 months, from their early childhood to the age of 10–15 years. Criteria for inclusion were set in advance; seven episodic narratives meeting these criteria were analyzed. Two types of changes in the narratives were observed, as expected: that of including other information, and that of an event suddenly being reported after no recall for several years. Information from the children's surroundings seemed to be substantially involved in these changes in their episodic narratives. The present results also indicate that mothers' episodic memories are not always reliable and that the schema children have can influence their episodic memories.     

物体颜色对情景记忆的影响

本研究采用ERP技术和学习-再认范式考察视觉输入的颜色和记忆中的物体颜色知识一致性对情景记忆编码和提取的影响。结果显示, 在对物体图片进行编码时颜色不一致图片诱发更大N400, 而提取阶段则对颜色一致图片有更多熟悉性加工(实验1); 物体名称能够更快激活典型颜色知识, 对颜色一致名称有更多细节回想(LPC更正) (实验2)。实验结果表明, 颜色一致促进知觉水平的记忆编码, 而阻碍语义水平编码。同时, 颜色一致促进物体图片提取(知觉水平)中的熟悉性和回想过程; 而对物体名称提取(概念水平)的促进作用仅表现在回想上。此外, 颜色与物体名称有着密切联系, 同样影响物体的语义表征, 支持激活-扩散模型理论。本研究从知觉和概念水平上为揭示物体颜色在联结记忆中的作用提供了证据。     

Bridging the gap between brain and behavior: cognitive and neural mechanisms of episodic memory

The notion that non-human animals are capable of episodic memory is highly controversial. Here, we review recent behavioral work from our laboratory showing that the fundamental features of episodic memory can be observed in rats and that, as in humans, this capacity relies on the hippocampus. We also discuss electrophysiological evidence, from our laboratory and that of others, pointing to associative and sequential coding in hippocampal cells as potential neural mechanisms underlying episodic memory.     

The effects of noise and gender on children's episodic and semantic memory

The main objectives in the present study were to examine meaningful irrelevant speech and road traffic noise effects on episodic and semantic memory, and to evaluate whether gender differences in memory performance interact with noise. A total of 96 subjects, aged 13-14 years (n = 16 boys and 16 girls in each of three groups), were randomly assigned to a silent or two noise conditions. Noise effects found were restricted to impairments from meaningful irrelevant speech on recognition and cued recall of a text in episodic memory and of word comprehension in semantic memory. The obtained noise effect suggests that the meaning of the speech were processed semantically by the pupils, which reduced their ability to comprehend a text that also involved processing of meaning. Meaningful irrelevant speech was also assumed to cause a poorer access to the knowledge base in semantic memory. Girls outperformed boys in episodic and semantic memory materials, but these differences did not interact with noise.     

The mark of adaptive memory in healthy and cognitively impaired older adults and elderly

The survival processing paradigm has recently drawn attention to the functional aspects of memory functioning. The survival effect, characterized by better memory performance when information is processed in a survival context, as compared with a variety of controls, is now well established in healthy populations. The main goal of this study was to test this paradigm in a group of cognitively impaired older adults and elderly; their data were compared to the data obtained in a group of healthy older adults and elderly. Seventeen cognitively impaired and 17 healthy participants performed a typical survival task using a blocked within‐subject design procedure and free recall as the memory test. The healthy older adults and elderly performed better on this memory task as well as on other tests included in a neuropsychological evaluation protocol. Importantly, both groups benefited from survival processing. These results provide further support for the power of survival processing, extending this phenomenon to cognitively impaired aging participants. The data also suggest that the survival effect is not simply a form of deep processing. Potential applied considerations are presented.     

Cross-modal working memory binding and word recognition skills: how specific is the link?

Recent research has suggested that the creation of temporary bound representations of information from different sources within working memory uniquely relates to word recognition abilities in school-age children. However, it is unclear to what extent this link is attributable specifically to the binding ability for cross-modal information. This study examined the performance of Grade 3 (8–9 years old) children on binding tasks requiring either temporary association formation of two visual items (i.e., within-modal binding) or pairs of visually presented abstract shapes and auditorily presented nonwords (i.e., cross-modal binding). Children’s word recognition skills were related to performance on the cross-modal binding task but not on the within-modal binding task. Further regression models showed that cross-modal binding memory was a significant predictor of word recognition when memory for its constituent elements, general abilities, and crucially, within-modal binding memory were taken into account. These findings may suggest a specific link between the ability to bind information across modalities within working memory and word recognition skills.     

老年人对情绪性事件的情景模拟:回忆过去与想象未来

研究采用自传体访谈技术,首次考察了老年人在对情绪性事件进行回忆和想象中生成的内部细节和外部细节数量,及其对回忆和想象内容的主观评估。结果发现:(1)无论是回忆还是想象任务,老年人都比年轻人提供了更少的内部细节和略多的外部细节;(2)与年轻人相似,老年人在想象未来积极事件时产生了更多的内部细节,表现出对积极信息的加工偏好;(3)老年人比年轻人更倾向于认为想象的事件与过去发生的事件相似度高,表明该群体在想象过程中更多地依赖了过去的记忆。该结果揭示了老年人对情绪性事件的回忆和想象特点,说明在回忆和想象过程中出现的与年龄有关的缺陷同样会体现在情绪性事件中,这很好地支持了建构性情景模拟假说。     

无关言语对汉字短时记忆系列回忆的影响*

采用视觉呈现字表和听觉呈现无关言语方式,探讨在字表项目保持期间阻止被试复述情况下,不同呈现位置的无关言语对汉字短时记忆系列回忆的影响。在字表保持期间,采用计算任务进行分心作业。实验结果发现：(1)无关言语对汉字短时记忆系列回忆成绩存在显著影响;(2)在字表保持期间阻止被试进行复述消除了字表呈现期间呈现无关言语对回忆成绩产生的干扰效应;(3)汉字短时记忆系列回忆成绩表现出系列位置效应。实验结果没有完全支持客体情节记忆模型。