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The nature of parietal involvement in visual short-term memory

视觉短期记忆中顶叶参与的本质

基本信息

批准号：
7647186
负责人：
Marian E Berryhill
金额：
$ 5.3万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-07-01 至 2010-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The aim of this revised proposal is to further detail the role of the posterior parietal cortex (PPC) in visual short-term memory (VSTM). A number of functional magnetic resonance imaging (fMRI) studies observe bilateral PPC activations during varied VSTM tasks. In contrast, PPC damage is not associated with generalized deficits in VSTM performance. Right PPC damage is known to impair spatial attention while left PPC damage is known to impair processing of numerical magnitude. The conflict between fMRI and patient data suggests several possibilities: VSTM deficits in PPC patients have not been carefully evaluated, or neuroimaging activations are epiphenomenal to VSTM task performance. In preliminary studies, I show that unilateral right PPC patients exhibit general impairment at VSTM for object, spatial and object-spatial VSTM for colors, novel shapes and tools stimulus categories. Left PPC patients do not exhibit general VSTM deficits, performing normally in the VSTM tasks. Bilateral PPC patients with simultanagnosia (the inability to see more than 1 thing at a time) are also globally impaired. Bilateral PPC also demonstrate sensitivity to experimental paradigm and performed worse in old/new VSTM recognition than in comparable recall tasks. The goal of the proposed studies is to investigate the parameters of PPC involvement in VSTM. Unresolved issues are addressed: the mechanism of VSTM impairment (encoding, maintenance, capacity, retrieval), whether recognition paradigms (old/new recognition versus 2 alternative forced-choice) affect bilateral PPC recognition performance, and whether left PPC activitations are due to involvement in processing magnitude. To accomplish this goal, I propose studies examining VSTM using complimentary approaches: neuropsychological studies of unilateral and bilateral parietal patients, as well as functional magnetic resonance imaging (fMRI) with normal subjects. PUBLIC HEALTH RELEVANCE: This set of studies is particularly relevant to the rehabilitation of parietal stroke patients. In the United States, stroke affects approximately 700,000 people annually, is the third leading cause of death, and is the leading cause of serious, long-term disability. Parietal lobe strokes are relatively common and the behavioral consequences on vision and action are devastating. In the proposed studies, VSTM impairments in parietal patients are evaluated. Deficits in VSTM have direct real-world implications relating to cognitive function. These data may provide affordable assessment measures and help guide rehabilitation strategies.

描述（由申请人提供）：本修订提案的目的是进一步详细说明后顶叶皮层（PPC）在视觉短期记忆（VSTM）中的作用。许多功能磁共振成像 (fMRI) 研究观察了不同 VSTM 任务期间双侧 PPC 的激活。相比之下，PPC 损伤与 VSTM 性能的普遍缺陷无关。已知右侧 PPC 损伤会损害空间注意力，而左侧 PPC 损伤会损害数值量级的处理。 fMRI 和患者数据之间的冲突表明了几种可能性：PPC 患者的 VSTM 缺陷尚未经过仔细评估，或者神经影像激活是 VSTM 任务表现的附带现象。在初步研究中，我表明单侧右侧 PPC 患者在物体、空间和物体空间 VSTM 颜色、新奇形状和工具刺激类别方面表现出普遍损伤。左侧 PPC 患者没有表现出一般的 VSTM 缺陷，在 VSTM 任务中表现正常。患有同时失认症（一次无法看到超过一件事）的双侧 PPC 患者也存在整体受损。双边 PPC 还表现出对实验范例的敏感性，并且在旧/新 VSTM 识别中的表现比在类似的回忆任务中表现更差。拟议研究的目标是调查 VSTM 中 PPC 参与的参数。解决了未解决的问题：VSTM 损伤的机制（编码、维护、容量、检索）、识别范式（旧/新识别与 2 个替代强制选择）是否影响双边 PPC 识别性能，以及左侧 PPC 激活是否是由于参与处理量级所致。为了实现这一目标，我建议使用补充方法检查 VSTM 的研究：对单侧和双侧顶叶患者的神经心理学研究，以及对正常受试者的功能磁共振成像 (fMRI)。公共卫生相关性：这组研究与顶叶中风患者的康复特别相关。在美国，中风每年影响约 70 万人，是第三大死因，也是导致严重、长期残疾的主要原因。顶叶中风相对常见，对视力和行动的行为影响是毁灭性的。在拟议的研究中，评估了顶叶患者的 VSTM 损伤。 VSTM 的缺陷对与认知功能相关的现实世界有直接影响。这些数据可以提供负担得起的评估措施并帮助指导康复策略。