Functional brain imaging of young, nondemented, and demented older adults
Functional brain imaging of young, nondemented, and demented older adults
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DOI：
10.1162/089892900564046
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发表时间：
2000-01-01
影响因子：
3.2
通讯作者：
Morris, JC
中科院分区：
文献类型：
--
作者：
Buckner, RL;Snyder, AZ;Morris, JC
基于功能 MRI (fMRI) 的脑成像为表征功能解剖学中与年龄相关的变化提供了强大的工具。然而，人群之间的比较面临着测量特性的潜在差异。本实验通过测量事件相关设计中的血流动力学反应特性，探讨了在非痴呆和痴呆老年人中进行功能磁共振成像研究的可行性。对 41 名参与者（14 名年轻人、14 名非痴呆老年人和 13 名痴呆老年人）进行了重复呈现感觉运动反应试验的范例。在一半的试验中，单个感觉运动事件是单独出现的，而另一半则是成对出现的。对孤立事件的血流动力学响应特征允许对受试者组之间的基本响应特性（例如幅度和方差）进行对比。配对事件进一步允许表征血流动力学响应的总和特性。为所有主题组生成了稳健且质量相似的激活图。定量结果表明，对于某些区域，例如视觉皮层，老年人的血流动力学反应幅度显着降低。在其他区域，例如运动皮层，观察到相对完整的反应特征。这些结果表明，在解释受试者组之间响应幅度的简单主效应时应谨慎行事。然而，在所有检查区域中，试验中血流动力学反应的总和在各组之间高度相似。后一项发现表明，即使受试者组之间确实存在绝对测量差异，也应保留相对激活变化。依赖于任务条件之间的群体交互、参数操作或区域之间的群体交互的设计应该为推断不同群体之间的功能解剖变化提供有价值的数据。
Brain imaging based on functional MRI (fMRI) provides a powerful tool for characterizing age-related changes in functional anatomy. However, between-population comparisons confront potential differences in measurement properties. The present experiment explores the feasibility of conducting fMRI studies in nondemented and demented older adults by measuring hemodynamic response properties in an event-related design. A paradigm involving repeated presentation of sensory-motor response trials was administered to 41 participants (14 young adults, 14 nondemented older adults, and 13 demented older adults). For half of the trials a single sensory-motor event was presented in isolation and in the other half in pairs. Hemodynamic response characteristics to the isolated events allowed basic response properties (e.g., amplitude and variance) between subject groups to be contrasted. The paired events further allowed the summation properties of the hemodynamic response to be characterized. Robust and qualitatively similar activation maps were produced for all subject groups. Quantitative results showed that for certain regions, such as in the visual cortex, there were marked reductions in the amplitude of the hemodynamic response in older adults. In other regions, such as in the motor cortex, relatively intact response characteristics were observed. These results suggest caution should be exhibited in interpreting simple main effects in response amplitude between subject groups. However, across all regions examined, the summation of the hemodynamic response over trials was highly similar between groups. This latter finding suggests that, even if absolute measurement differences do exist between subject groups, relative activation change should be preserved. Designs that rely on group interactions between task conditions, parametric manipulations, or group interactions between regions should provide valuable data for making inferences about functional-anatomic changes between different populations.