Investigating Cognitive and Neural Bases of Working Memory

 描述(申请人提供)：工作记忆指的是记住信息、处理信息并用它来指导行为的能力。它是一种基本的认知功能，支持计划、解决问题、语言理解和产生等高级能力；它是导致广泛的实验和“现实世界”人类表现测量的个体差异的重要因素；它的功能障碍是许多精神和神经疾病的特征。本提案的首要目标是解决工作记忆是如何工作的这个问题。通过关注注意力的作用。基于本项目上一个资助周期的发现，我们建议通过追求以下具体目标来考察注意机制对工作记忆成绩的贡献和边界条件：具体目标1：检验在注意和工作记忆任务中共同的注意相关因素是选择物体或特征的基础这一假说。在视觉中，自上而下的注意优先是通过场景中刺激的神经表征之间的有偏竞争机制来实现的。在实验1-4中，我们将使用多变量分析方法首先表征视觉搜索中有偏见竞争的时间动态，然后对视觉搜索和视觉工作记忆中的注意优先顺序的效果进行正面比较。具体目标2：检验“有注意的记忆项目”和“无人参与的记忆项目”的神经激活状态因策略因素而异的假设。有没有可能明确地将注意力集中在工作记忆中的信息上的神经基础与暂时离开注意力焦点的信息的保留联系起来？为了解决这个问题，我们将系统地改变视觉搜索敏感的两个因素：回溯的有效性；以及搜索的试验到试验的可预测性 目标。具体目标3：检验顶沟活动实现的假设 工作记忆中对注意力的语境适当控制。尽管在工作记忆任务中经常观察到“额顶背侧控制网络”中延迟期活动的增加，但在前一资助时期发表的研究对这一活动本身对应于刺激信息存储的观念提出了挑战。追求这一目标的实验将评估IPS作为一个动态优先图的作用，该图跟踪和管理与当前试验相关的项目的优先状态。

 DESCRIPTION (provided by applicant): Working memory refers to the ability to hold information in mind, to manipulate it, and to use it to guide behavior. It is an elemental cognitiv function that supports such high-level abilities as planning, problem solving, and language comprehension and production; it is an important factor underlying individual differences across a broad spectrum of experimental and "real world" measures of human performance; and its dysfunction is characteristic of many psychiatric and neurological diseases. The overarching goal of the present proposal is to address the question how does working memory work? by focusing on the role of attention. Building on findings from the previous funding cycle of this project, we propose to investigate the contributions, and boundary conditions, of attentional mechanisms to working memory performance, by pursuing the following Specific Aims: Specific Aim 1: To test the hypothesis that common attention-related factors underlie the selection of an object, or a feature, in both attention and working memory tasks. In vision, top-down attentional priority is implemented via the mechanism of biased competition among neural representations of stimuli in the scene. In Experiments 1-4, we will use multivariate analysis methods to first characterize the temporal dynamics of biased competition in visual search, then perform head-to-head comparisons of the effects of attentional prioritization in visual search vs. in visual working memory. Specific Aim 2: To test the hypothesis that the state of neural activation of `attended memory items' and of `unattended memory items' varies with strategic factors. Is it possible to definitively dissociate the neural bases of focusing attention on information held in working memory vs. the retention of this information when it is momentarily outside of the focus of attention? To address this question we will systematically vary two factors to which visual search is sensitive: the validity of retrocues; and the trial-to-trial predictability of the search target. Specific Aim 3: To test the hypothesis that activity in the intraparietal sulcus implements the context- appropriate control of attention in working memory. Although elevated delay-period activity is frequently observed in the "dorsal frontoparietal control network" during working memory tasks, research published during the previous funding period has challenged the notion that this activity corresponds to the storage, per se, of stimulus information. The experiments pursing this Aim will assess the idea that IPS functions as an amodal priority map that tracks and manages the priority status of items that are relevant for the current trial.