Visual search deficits in Parkinson's disease are attenuated by bottom-up target salience and top-down information
Visual search deficits in Parkinson's disease are attenuated by bottom-up target salience and top-down information
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DOI：
10.1016/j.neuropsychologia.2006.01.037
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发表时间：
2006-01-01
期刊：
影响因子：
2.6
通讯作者：
Mangels, Jennifer A.
中科院分区：
文献类型：
--
作者：
Horowitz, Todd S.;Choi, Won Yung;Mangels, Jennifer A.
帕金森病（PD）是一种主要影响黑质纹状体多巴胺系统的退行性疾病，在不相关刺激存在下，如视觉搜索任务中，帕金森病患者在选择任务相关刺激时表现出缺陷。然而，从以前的研究结果表明，这些赤字可能会有所不同的功能，选择是否必须主要依赖于“自下而上”的目标相对于背景刺激的显着性，或是否“自上而下”的信息的身份的目标是可用于偏见选择。在本研究中，中度至重度药物PD患者和年龄匹配的对照组进行了测试，对6个视觉搜索任务进行了系统的变化，自下而上的目标显着性（特征搜索，噪声特征搜索，连接搜索）和自上而下的目标知识（目标已知与目标未知）之间的关系。RT x集合大小函数的斜率和截距的比较提供了关于搜索和非搜索的效率的信息（例如，决策、响应）组件。随着自下而上目标显著性降低，患者表现出比对照组更高的截距，然而，与目标已知条件相比，目标未知条件下的这些缺陷不成比例地更大。PD和对照组之间的斜率差异仅限于目标未知结合条件，其中患者在目标缺失条件下表现出较浅的斜率，表明他们提前终止了搜索。这些结果表明，在高背景噪声的条件下，药物PD患者主要受损的决策和/或响应过程下游的目标搜索本身，并削弱赤字时，自上而下的信息可用于指导选择的目标信号。(c)2006爱思唯尔有限公司保留所有权利。
Patients with Parkinson's disease (PD), a degenerative disorder primarily affecting the nigrostriatal dopamine system, exhibit deficits in selecting task-relevant stimuli in the presence of irrelevant stimuli, such as in visual search tasks. However, results from previous studies suggest that these deficits may vary as a function of whether selection must rely primarily on the "bottom-up" salience of the target relative to background stimuli, or whether "top-down" information about the identity of the target is available to bias selection. In the present study, moderate-to-severe medicated PD patients and age-matched controls were tested on six visual search tasks that systematically varied the relationship between bottom-up target salience (feature search, noisy feature search, conjunction search) and top-down target knowledge (Target Known versus Target Unknown). Comparison of slope and intercepts of the RT x set size function provided information about the efficiency of search and non-search (e.g., decision, response) components, respectively. Patients exhibited higher intercepts than controls as bottom-up target salience decreased, however these deficits were disproportionately larger under Target Unknown compared to Target Known conditions. Slope differences between PD and controls were limited to the Target Unknown Conjunction condition, where patients exhibited a shallower slope in the target absent condition, indicating that they terminated search earlier. These results suggest that under conditions of high background noise, medicated PD patients were primarily impaired in decision and/or response processes downstream from the target search itself, and that the deficit was attenuated when top-down information was available to guide selection of the target signal. (c) 2006 Elsevier Ltd. All rights reserved.