Characterizing stimulus-response functions using nonlinear regressors in parametric fMRI experiments
Characterizing stimulus-response functions using nonlinear regressors in parametric fMRI experiments
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DOI：
10.1006/nimg.1998.0351
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发表时间：
1998-08-01
期刊：
影响因子：
5.7
通讯作者：
Friston, KJ
中科院分区：
文献类型：
--
作者：
Buchel, C;Holmes, AP;Friston, KJ
事实证明，参数研究设计对于表征正电子发射断层扫描研究中的实验参数（例如单词呈现率）和局部脑血流量之间的关系非常有用。在之前的论文中，我们提出了一种使用二阶多项式展开将刺激或任务参数的非线性函数拟合到血流动力学响应的方法。在这里，我们使用功能磁共振成像扩展这种方法来模拟 BOLD 响应和实验参数之间的非线性关系。我们提出了一个框架，允许在统计参数映射（SPM）使用的一般线性模型的背景下实现该技术。在这种情况下，统计推断基于 F 统计数据，在这方面，我们强调使用 F 字段的校正 P 值（即 SPM{F}）。该方法通过功能磁共振成像研究进行了说明，该研究着眼于提高听觉单词呈现率的效果。我们的参数设计使我们能够描述三个关键区域中不同形式的速率依赖反应：（i）双边额叶区域对单词的存在表现出分类反应，而与速率无关，表明该区域在建立认知（例如注意力）集方面发挥着作用； (ii) 在双侧枕颞区，激活随着字率的增加而线性增加； (iii) 后听觉关联皮层与语速呈非线性（倒U）关系。 (C) 1998 年学术出版社。
Parametric study designs proved very useful in characterizing the relationship between experimental parameters (e.g., word presentation rate) and regional cerebral blood flow in positron emission tomography studies. In a previous paper we presented a method that fits nonlinear functions of stimulus or task parameters to hemodynamic responses, using second-order polynomial expansions. Here we expand this approach to model nonlinear relationships between BOLD responses and experimental parameters, using fMRI. We present a framework that allows this technique to be implemented in the context of the general linear model employed by statistical parametric mapping (SPM). Statistical inferences, in this instance, are based on F statistics and in this respect we emphasize the use of corrected P values for F fields (i.e., SPM{F}). The approach is illustrated with a fMRI study that looked at the effect of increasing auditory word-presentation rate. Our parametric design allowed us to characterize different forms of rate-dependent responses in three critical regions: (i) bilateral frontal regions showed a categorical response to the presence of words irrespective of rate, suggesting a role for this region in establishing cognitive (e.g., attentional) set; (ii) in bilateral occipitotemporal regions activations increased linearly with increasing word rate; and (iii) posterior auditory association cortex exhibited a nonlinear (inverted U) relationship to word rate. (C) 1998 Academic Press.