工作记忆的认知模型与神经机制

本文评述了工作记忆认知模型的进展,阐述工作记忆神经机制研究的基本问题。研究者在工作记忆认知模型框架下,提出了工作记忆成分结构的脑模型。根据自己的研究探索,展望进一步的研究问题,以及TMS和fMRI/ERP等脑成像技术的结合运用对工作记忆认知神经科学研究的推动。     

任务无关情绪刺激对工作记忆信息更新的影响:来自ERP的证据

任务无关的情绪刺激如何对工作记忆的信息更新过程产生影响还不清楚。本研究采用情绪N-back任务,结合事件相关电位技术调查情绪对工作记忆信息更新的影响。ERP结果显示,在0-back任务中,负性分心物诱发的P3显著小于中性分心物,表明其干扰了工作记忆信息更新过程;而在2-back任务中,负性分心物诱发的P3与中性分心物没有显著差异,表明其未对信息更新表现出干扰效应。该结果支持了情绪与认知加工的双竞争模型。     

音乐对工作记忆影响及机制的ERP研究

以肖邦音乐为刺激材料,采用数字n-back实验范式来研究肖邦音乐对工作记忆的影响方式,并通过运用事件相关电位技术(ERP技术),研究不同音乐条件下,正常人大脑皮层的脑电活动情况,进而探讨音乐对工作记忆影响的神经机制。30名被试参加了3种音乐条件(无音乐、先导音乐、背景音乐)下的n-back(n=1、2)工作记忆任务的行为实验,收集行为数据;14名被试参加了同样实验过程的ERP实验,记录脑电数据。行为结果发现音乐条件对工作记忆效果有显著影响,且先导音乐条件下记忆效果最好;脑电结果显示P3波幅随记忆负荷的增加呈下降趋势,高记忆负荷水平下,P3波幅随先导音乐、背景音乐、无音乐的顺序逐渐呈现下降趋势;源定位分析发现音乐对工作记忆的促进作用可能跟大脑顶叶被激活有关。     

网络成瘾者工作记忆能力的ERP研究

旨在探究网络成瘾者和非成瘾者在言语工作记忆任务和视觉工作记忆任务中,面对网络相关刺激与网络无关刺激的ERP成分差异。利用词汇和图片材料,招募网络成瘾者以及非成瘾者各30名参加了N-back（N=2）工作记忆任务的ERP实验,同时记录行为数据及EEG,离线处理数据。结果发现：（1）在视觉工作记忆任务中,与网络无关图片相比,两组被试对网络相关图片的反应时显著更长,正确率也显著更低,而在言语工作记忆中无此显著差异;（2）非成瘾者面对网络相关图片产生的N2波幅显著高于网络无关图片,网络成瘾者对网络相关图片产生的P3波幅显著高于网络无关图片。两组差异表明网络成瘾者在言语工作记忆和视觉工作记忆上对网络相关刺激的早期加工存在差异,网络成瘾者对网络相关图片的视觉工作记忆水平较低。     

工作记忆表征精度加工需求对注意引导的影响

采用注意捕获范式, 通过行为和事件相关脑电位(ERP)实验, 探讨工作记忆表征精度加工需求对注意引导的影响, 行为结果发现, 在低精度加工需求条件下, 只有一个工作记忆表征引导注意, 且处于高激活状态的工作记忆表征产生的注意捕获大于低激活状态; 而在高精度加工需求条件下, 有两个工作记忆表征引导注意, 且处于高、低激活状态的工作记忆表征产生的注意捕获没有差异。ERP结果显示, 高精度加工需求条件下诱发的NSW和LPC大于低精度加工需求条件; 在高精度加工需求条件下, 干扰项与记忆项匹配比不匹配时, 诱发更大的N2和更小的N2pc, 而在低精度加工需求条件下, 干扰项与记忆项匹配和不匹配时诱发的N2、N2pc没有差异。研究表明, 工作记忆表征精度加工需求影响注意引导的机制可能是高精度加工需求下, 工作记忆表征消耗的认知资源增加, 搜索目标获得的资源减少, 干扰项捕获的注意增加。     

视觉搜索中基于工作记忆内容的注意捕获与抑制

注意是对有关信息的选择及对无关信息的抑制, 工作记忆是对有关信息的保持以及对无关信息的抑制, 两者在一定程度上都体现了选择性地指向与当前任务有关的刺激并同时抑制无关刺激。在系统地回顾已有研究的基础上结合新近的ERP研究, 从视觉搜索中基于工作记忆内容的注意捕获与注意抑制两个角度综述了视觉工作记忆与视觉选择性注意的相关研究。研究者们主要从两方面对该领域的问题进行了探讨：(1)视觉工作记忆内容对视觉选择性注意的导向作用; (2)视觉工作记忆内容对视觉选择性注意产生导向作用的条件。文章对以往的研究进行了总结, 指出了无论保持在视觉工作记忆的内容是捕获注意还是受到抑制, 都存在着自上而下和自下而上两种加工机制。     

空间及言语工作记忆任务的情绪效应：来自ERP/ fMRI的证据

情绪与工作记忆的关系问题是情绪和认知研究领域中的子课题。根据加工效能理论, 负性情绪, 特别是焦虑对认知的影响通常被看作是通过影响工作记忆来完成的。因此, 探讨负性情绪是如何作用于工作记忆, 将有助于完善和发展情绪与认知的理论, 为心境障碍疾病的诊断、治疗及干预提供依据, 既具有学术价值又具有一定的临床意义。本论文在前人研究的基础上, 采用事件相关电位(ERP)和功能磁共振技术(fMRI), 系统地考察了情绪和工作记忆三个子成分(语音环路、视空间模板及中央执行器)间的关系。本论文抓住了当前的热点问题, 从情绪和认知的关系入手, 将脑成像、电生理和行为方面的研究有机结合, 将时间动态研究与空间定位研究相结合, 为情绪和工作记忆相互作用的神经机制提供独到的证据, 验证且发展了情绪和认知关系的奠基理论—— 加工效能理论。     

网络成瘾者工作记忆水平受影响的机制:来自ERP的证据

本研究采用事件相关电位技术(ERP),以N-back范式为实验任务,考察20名网络成瘾大学生和23名对照组大学生的工作记忆水平,结果发现:对照组的工作记忆具有一定加工优势的趋势,正确率高于成瘾组,反应时低于成瘾组,但均未达到显著差异。网络成瘾组与对照组工作记忆加工时,网络成瘾组P2波幅更高,N2波幅更低,N2潜伏期更长,说明与网络成瘾组相比,对照组工作记忆水平更高。     

线条朝向的空间构型对视觉工作记忆表征的影响

采用行为实验和事件相关电位技术(ERP),通过整体检测的变化觉察范式,探讨线条朝向的空间构型对视觉工作记忆表征的影响及机制。行为结果发现,水平排列线条朝向的视觉工作记忆成绩高于杂乱排列; 水平排列线条朝向有框时的视觉工作记忆成绩低于无框条件; ERP结果发现,无框条件下水平排列的线条朝向诱发的对侧延迟活动的波幅小于有框条件。以上结果说明,水平排列的空间构型能够促进线条朝向的视觉工作记忆表征,这一促进作用的潜在机制可能是水平排列的空间构型能够降低信息表征的负荷。     

工作记忆对知觉类别学习的影响:问题与构想

人们学习将感知到的客体按照不同的标准或规则分类存储,即类别学习。而工作记忆作为多种认知加工的基础,对类别学习具有重要作用。基于已有研究,分别梳理了言语工作记忆和视空工作记忆对基于规则和信息整合类别结构的影响。目前,执行功能是否影响内隐类别学习系统、工作记忆负荷对内隐外显类别学习系统的影响是否一致还存在争议。此外,工作记忆影响知觉类别学习的认知加工阶段尚不清晰。未来的研究还需明确工作记忆负荷对内隐和外显类别学习的影响,进一步验证工作记忆影响类别学习的认知加工阶段假设的合理性。     

Susceptibility of spatial and verbal working memory to demands of the central executive

We used a dual-task paradigm to examine the degree to which domain-specific spatial and verbal subsystems depend on the domain-general central executive. Forty participants were asked to retain spatial or verbal information while performing a concurrent secondary task related to simple arithmetic. The secondary tasks consisted of three cognitive processes: single-digit addition, a digit-carrying operation, and digit reading. The single-digit addition and carry operation include central executive functioning, while digit reading relies solely on the phonological loop. The single-digit addition caused a performance decrement on the spatial working memory task, while the digit reading impaired performance on the verbal working memory task. The carry operation interfered with recall accuracy on both working memory tasks. The spatial working memory task was significantly correlated with the verbal working memory task only when the secondary task was more demanding on the central executive. Our results suggest that spatial working memory rather than verbal working memory is susceptible to failure of central executive functioning and that the central executive plays an important role in regulating the cognitive demands of different domains.     

内隐序列学习与中央执行功能的关系

内隐序列学习与一般认知的关系一直处于争议之中。近年来,越来越多的研究显示内隐序列学习与工作记忆（尤其是中央执行功能）存在显著关联。基于此,本研究通过两个实验来探测两者的相关及机制。实验1从行为与脑电两个角度探讨经典位置序列学习与中央执行功能的相关,发现经典位置序列学习的内隐习得量与中央执行功能的抑制、刷新功能的强度呈负相关,与转换功能没有显著相关,脑电结果也支持了这一结论。实验2在内隐序列学习中加入认知冲突来增加中央执行功能的负荷。结果发现在高抑制功能负荷任务条件下,内隐习得量与抑制功能强度的相关性发生了反转,进一步证明内隐序列学习与中央执行功能的抑制子成分在脑功能上的关系：不同条件下呈现竞争、协作等不同状态。     

Working memory as a predictor of written arithmetical skills in children: The importance of central executive functions

Background . The study was conducted in an attempt to further our understanding of how working memory contributes to written arithmetical skills in children. Aim . The aim was to pinpoint the contribution of different central executive functions and to examine the contribution of the two subcomponents of children's written arithmetical skills. Sample and method . A total of 141 third‐ and fourth‐graders were administered arithmetical tasks and measures of working memory, fluid IQ and reading. Regression analysis was used to examine the relationship between working memory and written arithmetical skills. Results . Three central executive measures (counting span, trail making and verbal fluency) and one phonological loop measure (Digit Span) were significant and predictors of arithmetical performance when the influence of reading, age and IQ was controlled for in the analysis. Conclusions . The present findings demonstrate that working memory, in general, and the central executive, in particular, contribute to children's arithmetical skills. It was hypothesized that monitoring and coordinating multiple processes, and accessing arithmetical knowledge from long‐term memory, are important central executive functions during arithmetical performance. The contribution of the phonological loop and the central executive (concurrent processing and storage of numerical information) indicates that children aged 9–10 years primarily utilize verbal coding strategies during written arithmetical performance.     

6-9岁儿童工作记忆的发展研究

以Baddeley工作记忆模型为基础考察儿童语音环路、视觉空间模板、中央执行的发展及其与复杂广度的关系。225名6-9岁被试完成9个任务,分别测量听力广度及工作记忆三个子系统的功能。发现工作记忆各个子成分的功能在6-9岁期间发展速度不同;中央执行与语音环路和视觉空间模板的联系随年龄增长加强;结构方程模型分析发现中央执行和语音环路功能对儿童听力广度都有显著的直接影响,表明言语复杂广度任务既涉及中央执行功能也涉及语音环路的存贮功能。     

语文学习困难儿童的工作记忆与加工速度

加工速度和工作记忆反应了不同的认知加工过程,在认知发展研究中,加工速度和工作记忆所起的作用仍存在较大的分歧.采用多因素混合实验设计,在严格控制条件下,比较了语文学习困难和控制组儿童的工作记忆和加工速度.结果发现,与控制组相比,语文学习困难儿童在工作记忆和加工速度方面均存在明显的不足,但加工速度不能解释不同能力组之间的差异,语文学习困难儿童的缺陷在于工作记忆能力的下降.工作记忆的缺陷在于言语工作记忆和中央执行功能的不足,与视空间工作记忆能力无关.语文学习困难既存在一般的工作记忆缺陷(中央执行功能)也存在特定的工作记忆(言语工作记忆)能力的不足.     

Book Reviews

There is long-standing evidence for verbal working memory impairments in both children and adults with dyslexia. By contrast, spatial memory appears largely to be unimpaired. In an attempt to distinguish between phonological and central executive accounts of the impairments in working memory, a set of phonological and spatial working memory tasks was designed to investigate the key issues in working memory, task type, task demands (static, dynamic, and updating), and task complexity. Significant differences emerged between the dyslexic and nondyslexic participants on the verbal working memory tasks employed in Experiment 1, thereby providing further evidence for continuing dyslexic impairments of working memory into adulthood. The nature of the deficits suggested a problem with the phonological loop, with there being little evidence to implicate an impairment of the central executive. Due to the difficulties associated with separating verbal working memory and phonological processing, however, performance was investigated in Experiment 2 using visuospatial measures of working memory. The results of the visuospatial tasks indicated no between-group differences in static spatial memory, which requires the short-term storage of simultaneously presented information. In almost all conditions there were no between-group differences in dynamic spatial memory that demands the recall of both location and order of stimuli presented sequentially. However, a significant impairment occurred on the dynamic task under high memory updating load, on which dyslexic adults showed nonphonological working memory deficits. In the absence of an explanation involving verbal recoding, this finding is interpreted in terms of a central executive or automaticity impairment in dyslexia.     

Competing Core Processes in Attention-Deficit/Hyperactivity Disorder (ADHD): Do Working Memory Deficiencies Underlie Behavioral Inhibition Deficits?

The current study examined competing predictions of the working memory and behavioral inhibition models of ADHD. Behavioral inhibition was measured using a conventional stop-signal task, and central executive, phonological, and visuospatial working memory components (Baddeley 2007) were assessed in 14 children with ADHD and 13 typically developing (TD) children. Bootstrapped mediation analyses revealed that the visuospatial working memory system and central executive both mediated the relationship between group membership (ADHD, TD) and stop-signal task performance. Conversely, stop-signal task performance mediated the relationship between group membership and central executive processes, but was unable to account for the phonological and visuospatial storage/rehearsal deficits consistently found in children with ADHD. Comparison of effect size estimates for both models suggested that working memory deficits may underlie impaired stop-signal task performance in children with ADHD. The current findings therefore challenge existing models of ADHD that describe behavioral inhibition as a core deficit of the disorder.     

工作记忆对时间加工的影响

非时间信息加工与时间加工的关系是复杂的, 存在双向干扰或单向干扰, 结果的不一致与任务所需的注意资源及工作记忆都有关。工作记忆的中央执行系统在时间加工中起主要作用, 同时进行的非时间任务对中央执行功能的需求越多, 两种任务之间的干扰程度越大。语言环和视空间模板对时间加工的影响与非时间信息的类型有关。工作记忆作为一个整体以工作记忆容量为指标, 计时成绩也表现出与工作记忆容量有关的年龄、智力等方面的差异。时间加工和工作记忆在额叶、顶叶、基底神经节等皮质存在共同的神经机制。未来应该丰富工作记忆的研究内容, 结合时间加工的分段性探讨工作记忆影响时间加工的具体进程及神经机制, 并力求在应用方面取得一定的成果。     

Age-related changes in duration reproduction: involvement of working memory processes

The aim of the present research was to study age-related changes in duration reproduction by differentiating the working memory processes underlying this time estimation task. We compared performances of young and elderly adults in a duration reproduction task performed in simple and concurrent task conditions. Participants were also administered working memory tests to measure storage and central executive functions. Findings indicated a differential involvement of working memory storage and central executive functions in age-related differences in temporal tasks. The limited storage capacities explained age-related changes in the simple task of duration reproduction, and the dysfunctioning of central executive functions accounted for age-related changes in duration reproduction performed in a concurrent task condition, which involves greater attentional resources.     

学龄儿童工作记忆结构的验证研究

该研究目标是验证儿童工作记忆是否符合Baddeley提出的由中央执行、情景缓冲区、语音环路及视觉空间模板构成的四成分模型。211名6~9岁小学生完成9个工作记忆任务,这些任务分别测量工作记忆四个子成分的功能。验证性因素分析表明,四因素模型比三因素模型和单因素模型更好地拟合数据。在小学阶段儿童工作记忆不是一个单一的结构,已经分化为四个子成分构成的记忆系统。