Assessment of Prospective Memory using fNIRS in Immersive Virtual Reality Environment

In order to measure real life prospective memory (PM) ability in laboratory setting, previous studies have used photograph-based, video-based and virtual reality (VR)-based to simulate real life environment. In this study, we used the Functional Near-Infrared Spectroscopy (fNIRS) to record participants’ brain activities when they are performing PM tasks in immersive VR environment. 10 participants were asked to perform PM tasks in a virtual environment while wearing a VR headset and an fNIRS device. By comparing the hemodynamic changes of rostral prefrontal cortex (BA10) of the PM component and the ongoing component, the result shows that VR PM task can induce the activation of BA10. In addition, by making use of the fNIRS technique, this study provides a feasible way to measure BA10 activity in simulated real life environment using immersive VR device.

Cognitive Demand and Reminders Effect on Time-Based Prospective Memory in Amnesic Mild Cognitive Impairment (AMCI) and in Healthy Elderly

Individuals with-Mild Cognitive Impairment (MCI) often complain of difficulty remembering to carry out intended actions. We investigated the relative efficacy of a different reminder in performing a time-based Prospective Memory (PM) task. The PM performance of 24 participants with amnesic Mild Cognitive Impairment (AMCI) has been compared with that of 24 healthy controls. As ongoing task, samples of the Attentive Matrices Test were used. In the PM task subjects were requested to write an “X” every three minutes during a 9 minutes period. Participants received the task consisting either in a low demand condition (checking number “5”) or in a high demand condition (checking numbers “1”, “4”, “9”). In order to be as punctual as possible, participants were asked to simultaneously write the “X” at task time expiration, using a digital clock. Time monitoring was recorded. Reminder occurring was manipulated in that participants could receive critical, accidental or completely absent reminder. As expected, high cognitive demand was negatively correlated with PM performance and time monitoring. Unexpectedly, all the participants did not benefit from the critical reminder. These findings demonstrated, from a behavioral perspective, that Working Memory (WM) and PM processes are not based on the same memory system and PM may require WM resources at high demand.

Prospective Memory Assessment,before and after the Use of Concentrated Extract of Soy,in Postmenopausal Women Complaining of Memory Impairment

Objective: To evaluate the performance of a sample of postmenopausal women complaining of decline of prospective memory, undergoing therapy with concentrated extract of soy (CES) for six months, through specific neuropsychological assessment, developed for this purpose. Materials and Methods: A randomized and double-blind study was with 90 women, 12-month amenorrhea, 40 years to 65 years and body mass index (BMI) above 30 kg/m2, whose complaints were reduction of cognitive efficiency. The participants were randomly divided into two treatment groups: Group I— received one capsule of 150 mg extract of soy, with 60 mg isoflavones orally/day;Group II—received one capsule placebo, for six months. All participants underwent a detailed interview, the MMSE, depression scale, and as they were being included in the study, self-perception scales and neuropsychological tests before and after six months of treatment. For analysis purposes, we applied the ANOVA and t-student tests. Results: Our results suggest a possible positive effect regarding the improvement in verbal fluency and executive function tasks of planning and mental flexibility, in women undergoing therapy with concentrated extract of soy in postmenopause. There was no correlation between prospective memory and cognitive performance, and there were only intensity scores of the depressive symptoms. Conclusion: Isoflavones act favorably on the cognitive function, amongst all functions, only on verbal memory and executive function tasks of planning and mental flexibility. The others showed no signs of improvement. We concluded that concentrated extract acts only on some cognitive functions.

周期性干旱下桂花滞尘能力的变化及其生理响应

干旱的反复发生会导致植物自身产生胁迫记忆,进而会对植物的滞尘能力产生影响,然而,干旱胁迫记忆如何影响植物的滞尘效率及植物的生理响应和适应尚未明确。通过向开顶式气室(OTCs)内输送机动车尾气,停止供水达到干旱,分别设置尾气胁迫组(P)、干旱胁迫组(D)、双胁迫组(PD)和对照组(CK)4个处理组。每个周期性胁迫设置为期12 d,恢复期也为12 d。结果表明,桂花叶片表面滞尘量在P组下由S1周期的33.77μg·cm^(-2)下降到S3的21.32μg·cm^(-2),PD组下由S1周期的38.08μg·cm^(-2)下降到S3的25.70μg·cm^(-2);蜡质层滞尘量在P组呈显著性下降(P<0.001),在PD组中下降不显著。植物体内抗氧化酶活性随着周期处理而逐渐减小,可溶性糖含量先上升后下降,叶绿素含量与颗粒物在第2阶段呈显著负相关,第3周期并无显著相关性。表明反复干旱下提高了植物生理对胁迫的适应性,说明植物的胁迫记忆可以帮助植物更好地应对再次到来的胁迫。

隐蔽线索对基于时间前瞻记忆的影响

本研究通过三个实验,从不同角度考察隐蔽线索对基于时间前瞻记忆的影响,以期进一步了解基于时间前瞻记忆的加工特点。实验1A旨在考察不同进行中任务线索条件下基于时间前瞻记忆的表现差异;实验1B旨在考察不同干扰任务条件下的线索对基于时间前瞻记忆的影响;实验2旨在考察嵌入不同的前瞻记忆任务线索和进行中任务线索对基于时间前瞻记忆的影响。结果表明:(1)适当的隐蔽线索对个体的基于时间前瞻表现具有促进作用。对于提示回溯成分的隐蔽线索,时间线索无论隐藏在进行中任务中还是干扰任务中都显著提高被试基于时间前瞻记忆的表现。(2)与出现在干扰任务阶段中的线索相比,出现在进行中任务阶段中的线索更能提高个体基于时间前瞻记忆的表现,说明线索越临近目标时间,促进效应越大。(3)基于时间范式的线索能够促进基于时间前瞻记忆表现,基于事件的线索则不能。本研究结果支持随机游动模型。

酒精摄入对前瞻记忆的损伤:影响因素及作用机制

日常生活中绝大多数活动的完成都与前瞻记忆存在密切联系。酒精摄入会损伤大脑结构和认知功能,降低个体前瞻记忆表现。酒精摄入与前瞻记忆的关系受诸多因素影响,主要包括酒精摄入模式和剂量、其他物质滥用、测量方式以及前瞻记忆类型。酒精摄入影响前瞻记忆的认知机制主要涉及执行功能和注意系统。神经机制方面,酒精摄入影响前瞻记忆的脑区包括前额叶、顶枕叶、边缘系统(海马、前扣带回、上丘脑)、大脑皮质和髓质等。未来研究可进一步揭示酒精摄入对前瞻记忆成分及各加工阶段的影响,重视研究方法的差异和改进,关注改善临床酒精摄入人群前瞻记忆的因素。

3~6岁ASD儿童基于事件前瞻记忆的损伤:执行功能的作用

为了解3~6岁自闭症儿童基于事件前瞻记忆能力的发展特点和损伤机制,本研究采用实验室前瞻记忆范式,比较了自闭症儿童与正常儿童基于事件的前瞻记忆和执行功能表现。结果显示,相比于正常儿童,自闭症儿童基于事件前瞻记忆表现存在明显缺陷。而且,自闭症儿童基于事件的前瞻记忆受损与其执行功能障碍有相关,自闭症儿童抑制控制能力的发展显著预测其基于事件的前瞻记忆能力。

金属磁记忆检测技术研究综述

金属磁记忆(MMM)是一种新兴的无损检测技术,具有在弱磁条件下表征铁磁材料裂纹和应力损伤的显著优势,从而评估构件的可用性。总结了过去十年金属磁记忆领域的研究进展,涵盖了磁机械效应机理、实验研究、损伤评估和影响因素。通过对磁/应力耦合效应的理论研究、影响检测信号的因素、损伤状态的判断标准和缺陷识别等方面的综合分析,总结了金属磁记忆技术的优点和关键问题。另外,总结并展望了未来应重点关注探索铁磁领域的微观尺度、发展磁机械耦合模型等,以拓展金属磁记忆测试在工程领域的实际应用。

Microwave sintering effects on the microstructure and mechanical properties of Ti–51at%Ni shape memory alloys

Ti–51at%Ni shape memory alloys(SMAs) were successfully produced via a powder metallurgy and microwave sintering technique.The influence of sintering parameters on porosity reduction,microstructure,phase transformation temperatures,and mechanical properties were investigated by optical microscopy,field-emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),differential scanning calorimetry(DSC),compression tests,and microhardness tests.Varying the microwave temperature and holding time was found to strongly affect the density of porosity,presence of precipitates,transformation temperatures,and mechanical properties.The lowest density and smallest pore size were observed in the Ti–51at%Ni samples sintered at 900°C for 5 min or at 900°C for 30 min.The predominant martensite phases of β2 and β19′ were observed in the microstructure of Ti–51at%Ni,and their existence varied in accordance with the sintering temperature and the holding time.In the DSC thermograms,multi-transformation peaks were observed during heating,whereas a single peak was observed during cooling;these peaks correspond to the presence of the β2,R,and β19′ phases.The maximum strength and strain among the Ti–51at%Ni SMAs were 1376 MPa and 29%,respectively,for the sample sintered at 900°C for 30 min because of this sample's minimal porosity.

Recent Advances in Variable Flux Memory Machines for Traction Applications: A Review

This paper overviews the recent advances in variable flux memory machines(VFMMs)for traction applications with particular reference to newly emerged machine topologies and related control strategies.Due to the use of flux memorable low coercive force(LCF)magnets,the air-gap flux of VFMM can be flexibly varied via a magnetizing current pulse.Thus,the copper loss associated with the flux weakening current and high-speed iron loss can be significantly reduced,and hence high efficiency can be achieved over a wide speed and torque/power operation.These merits make VFMM potentially attractive for electric vehicle(EV)applications.Various novel VFMMs are reviewed with particular reference to their topologies,working principle,characteristics and related control techniques.In order to tackle the drawbacks in the existing VFMMs,some new designs are introduced for performance improvement.Then,the electromagnetic characteristics of an exemplified EV-scaled switched flux memory machine and various benchmark traction machine choices,such as induction machine,synchronous reluctance machines,as well as commercially available Prius 2010 interior permanent magnet(IPM)machine are compared.Finally,the key challenges and development trends of VFMM are highlighted,respectively.

Modeling of Pneumatic Muscle with Shape Memory Alloy and Braided Sleeve

Pneumatic muscle （PM） of flexible actuators used in bionic robot is an active area of recent research. A novel PM with shape memory alloy （SMA） braided sleeve is proposed in this paper, and SMA is used to improve PM working characteristics. Based on the principle of virtual work, output force model of PM and relationship with braided wire inner-stress are established, and analysis of PM deformation has shown that braided wire length is the key factor of output force characteristic. Based on the crystal structure transitions, the relationship of temperature with wire shrinkage is derived. Then, the synthetic dynamics of novel PM is established. A physical prototype of PM with SMA braided sleeve is developed, and test platform that is built for the experiment. Experiment and simulation test of static isometric-length, static isobaric-pressure, and dynamic characteristics are done. The experimental results are compared with the simulation of theoretical model. Moreover, based on experiment, model of output force was improved by adding a correction factor to deal with the elastic force of rubber tube. The results analysis demonstrates that the established models are correct, and SMA wires can reinforce PM and make PM working characteristics adjustable. PM proposed in this paper has greater output force and is beneficial to achieve more accurate control that is useful for manipulating fragile things.

A Self-Organizing Memory Neural Network for Aerosol Concentration Prediction

Haze-fog,which is an atmospheric aerosol caused by natural or man-made factors,seriously affects the physical and mental health of human beings.PM2.5(a particulate matter whose diameter is smaller than or equal to 2.5 microns)is the chief culprit causing aerosol.To forecast the condition of PM2.5,this paper adopts the related the meteorological data and air pollutes data to predict the concentration of PM2.5.Since the meteorological data and air pollutes data are typical time series data,it is reasonable to adopt a machine learning method called Single Hidden-Layer Long Short-Term Memory Neural Network(SSHL-LSTMNN)containing memory capability to implement the prediction.However,the number of neurons in the hidden layer is difficult to decide unless manual testing is operated.In order to decide the best structure of the neural network and improve the accuracy of prediction,this paper employs a self-organizing algorithm,which uses Information Processing Capability(IPC)to adjust the number of the hidden neurons automatically during a learning phase.In a word,to predict PM2.5 concentration accurately,this paper proposes the SSHL-LSTMNN to predict PM2.5 concentration.In the experiment,not only the hourly precise prediction but also the daily longer-term prediction is taken into account.At last,the experimental results reflect that SSHL-LSTMNN performs the best.

基于Cuk变换器的永磁记忆电机调磁控制

针对永磁记忆电机(permanent magnet memory motor,PM-MM)调磁控制中存在的电压限制问题,提出一种基于Cuk变换器的控制策略。首先分析随着PM-MM调磁速度的增加,电压限制问题对系统稳定性的影响;在此基础上利用Cuk变换器的原理,结合PM-MM的数学模型,针对调磁过程中的电压限制问题,提出了一种基于Cuk变换器的PM-MM调磁控制策略,并以一台20 kW的PM-MM为被控对象进行仿真研究。结果表明:所提策略能有效补偿电机调磁过程中所需的电压,大幅抑制了充磁过程中的转矩及转速的波动,提高了系统的稳定性。

老年维持性血液透析病人前瞻记忆现状调查

目的本研究旨在探索老年维持性血液透析(MHD)病人前瞻性记忆(PM)水平,并探讨其相关影响因素。方法纳入东南大学附属中大医院血液净化中心老年病人60例为MHD组,与其年龄匹配的非MHD人群60例为对照组。对2组对象分别进行神经心理学评估,包括MMSE、语言流畅性测试(VFT)、数字广度测试(DST)、Rey听觉语言学习测试(RAVLT)、Stroop颜色词干扰测试(SCWT),以及基于时间(TB)的前瞻记忆任务测试(TBPM)和基于事件的前瞻记忆任务测试(EBPM)。结果2组在DST中的表现差异无统计学意义(P>0.05)。MHD组MMSE得分低于对照组(P<0.01),SCWT反应时间长于对照组(P<0.01),RAVLT(长时延迟回忆)及VFT(水果)中的表现差于对照组(P<0.01)。MHD组EBPM、TBPM得分和查看时钟频次均显著低于对照组(P<0.01)。结论老年MHD病人存在EBPM和TBPM下降,对其进行PM评估可能有助于筛查认知功能障碍。

儿童前瞻记忆:执行功能的作用

前瞻记忆是指在未来某一恰当时间或情境中,记得完成先前计划好的事件或活动的记忆。受认知发展水平限制,执行功能各子成分(工作记忆、抑制控制、认知灵活性)在儿童前瞻记忆加工过程中起不同作用。其中,工作记忆在意向编码和维持阶段发挥重要作用,该成分对前瞻记忆的影响主要在儿童早期。而抑制控制和认知灵活性则在意向提取和执行阶段中起关键作用,这两个子成分对前瞻记忆的影响主要在儿童中后期。未来在考察儿童前瞻记忆与执行功能关系时需改进研究方法,选取适合儿童的任务范式和理论模型,在同一样本中对不同类型前瞻记忆综合探究并增加纵向研究证据。另外,还需深入考察不同类型前瞻记忆与执行功能的关系,并进一步揭示执行功能对儿童前瞻记忆成分及各加工阶段的影响。

工作记忆、靶线索间隔时间对事件性前瞻记忆的影响

采用双重任务研究范式,系统考察了不同类型的工作记忆负荷、靶线索间隔时间对事件性前瞻记忆(EBPM)两成分(前瞻成分、回溯成分)的影响。结果显示:工作记忆负荷对EBPM有显著影响,具体表现为高负荷工作记忆条件下EBPM成绩差于低工作记忆负荷;靶线索间隔时间对EBPM有显著影响,长时间间隔条件下被试的作业表现较差,而且间隔时间对EBPM两成分的影响没有受到工作记忆任务类型的影响;较之于前瞻成分,回溯成分更容易受到工作记忆负荷的影响;不同工作记忆类型对前瞻记忆两成分任务有不同影响,回溯成分任务更容易受客体工作记忆的影响。综合来看,研究结果支持了“预备注意加工和记忆加工”理论。

线索聚焦性影响前瞻记忆意向维持与提取:来自眼动追踪的证据

研究以眼动追踪的方法探讨线索聚焦性对前瞻记忆(PM)加工过程的影响。实验1中,28名被试完成了线索聚焦和非聚焦两类PM眼动追踪任务。结果发现,个体在聚焦和非聚焦两类PM任务意向维持、意向提取阶段上均表现出不同的眼动加工特征。实验2中,研究进一步对线索聚焦和非聚焦两个PM任务中PM线索词重复次数进行平衡,并重复了实验1的研究结果,说明实验1所观测到的效应不是PM线索词重复造成的混淆,线索聚焦性影响PM的意向维持、意向提取过程,研究结果支持多重加工理论。

任务和个体特征对事件性前瞻记忆后效的影响及其机制

前瞻记忆后效(aftereffects of prospective memory)是指个体错误地重复执行已完成的前瞻记忆意向或已完成的意向对进行中任务产生干扰的现象。基于前瞻记忆多重加工理论,通过对文献梳理发现,任务特征(前瞻记忆任务特征、进行中任务特征、任务情境)和个体特征会调节事件性前瞻记忆后效。目前,关于事件性前瞻记忆后效的加工机制的理论解释主要包括自动化加工、控制加工、提取−抑制加工、停止标记加工、双加工和动态多重加工等。其中,自动化加工可分为反射−联结加工和差异−搜索加工,而控制加工又可分为监控加工和抑制加工。事件性前瞻记忆后效的形成与自动化加工和监控加工关系更密切,而后效的消退更依赖抑制加工。未来研究需深入考察事件性前瞻记忆后效的加工机制,增加对不同类型以及自然情境中前瞻记忆后效的考察,注重探究降低前瞻记忆后效的策略。

Neural basis for successful encoding and retrieval of prospective memory

Prospective memory (PM) refers to memory for future intentions.Difference due to memory (Dm effect) is the difference in neural activity related to stimuli that were subsequently remembered or forgotten.Using event-related potentials (ERPs),the present study investigated the Dm effect for PM using a subsequent task-switching paradigm.The results showed that a Dm effect of ERP P150 was more positive-going for later PM hit trials than for later PM forgotten trials during 100–200 ms.This Dm effect may reflect the process for the production of future intention or the process for attention.Consistent with previously reported Dm effects of other types of memory,we found that the fbN2 (250–280 ms) and late positivity component (400–700 ms) were stronger in later PM hit trials than in forgotten trials.The fbN2 was evoked by Chinese characters.The late positivity component was related to the precise encoding process.In conclusion,because of the early P150,PM encoding appears to be somewhat different from previously identified Dm effects.However,further research is needed.Our findings reveal that Dm effects of PM share similar characteristics with known Dm effects of other types of episodic memory after the very early stage of neural processing.

孤独症谱系障碍个体前瞻记忆的元分析

运用元分析方法探究孤独症谱系障碍个体前瞻记忆受损情况,区分孤独症谱系障碍个体基于时间与基于事件的前瞻记忆表现差异,并分析相关的影响因素。结果表明,孤独症谱系障碍个体前瞻记忆存在中度缺损,基于时间的前瞻记忆存在严重缺损,基于事件的前瞻记忆存在轻度缺损。调节变量分析发现,ASD个体的前瞻记忆损伤独立于其年龄、言语智商等因素。