Defining the Face Processing Network: Optimization of the Functional Localizer in fMRI
Defining the Face Processing Network: Optimization of the Functional Localizer in fMRI
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DOI：
10.1002/hbm.20630
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发表时间：
2009-05-01
影响因子：
4.8
通讯作者：
Barton, Jason J. S.
中科院分区：
文献类型：
--
作者：
Fox, Christopher J.;Iaria, Giuseppe;Barton, Jason J. S.
在面部处理的功能磁共振成像研究中，通常使用在查看面部和物体时对比大脑信号的功能定位器。然而，当使用保守的统计阈值时，当前的协议并不能可靠地显示所有受试者面部处理核心系统的所有区域，这在单个受试者的研究中是有问题的。此外，所应用阈值的任意变化与面部选择性感兴趣区域（ROI）大小的不一致估计相关。我们假设在定位器中使用更自然的动态面部图像可能会增加识别个体受试者中的面部选择性 ROI 的可能性，并且我们还研究了使用一种方法来导出独立于阈值的统计最佳 ROI 簇大小。我们发现动态面部刺激比静态刺激更有效，在核心面部处理系统中识别 98%（静态为 72%）的 ROI，在扩展面部处理系统中识别 69%（静态为 39%）的 ROI。然后，我们确定每个核心面部处理 ROI、与最大统计面部选择性相关的簇大小，对于梭状面部区域、枕面部区域和后上颞沟，其平均约为 50 mm(3)。我们建议，（a）由动态面部定位器诱导的更鲁棒的面部相关活动和（b）基于最大面部选择性的簇大小确定的组合增加了个体受试者中面部相关 ROI 表征的敏感性和特异性。 Hum Brain Mapp 30:1637-1651, 2009。(C) 2008 Wiley-Liss, Inc.
Functional localizers that contrast brain signal when viewing faces versus objects are commonly used in functional magnetic resonance imaging studies of face processing. However, current protocols do not reliably show all regions of the core system for face processing in all subjects when conservative statistical thresholds are used, which is problematic in the study of single subjects. Furthermore, arbitrary variations in the applied thresholds are associated with inconsistent estimates of the size of face-selective regions-of-interest (ROIs). We hypothesized that the use of more natural dynamic facial images in localizers might increase the likelihood of identifying face-selective ROIs in individual subjects, and we also investigated the use of a method to derive the statistically optimal ROI cluster size independent of thresholds. We found that dynamic facial stimuli were more effective than static stimuli, identifying 98% (versus 72% for static) of ROIs in the core face processing system and 69% (versus 39% for static) of ROIs in the extended face processing system. We then determined for each core face processing ROI, the cluster size associated with maximum statistical face-selectivity, which on average was approximately 50 mm(3) for the fusiform face area, the occipital face area, and the posterior superior temporal sulcus. We suggest that the combination of (a) more robust face-related activity induced by a dynamic face localizer and (b) a cluster-size determination based on maximum face-selectivity increases both the sensitivity and the specificity of the characterization of face-related ROIs in individual subjects. Hum Brain Mapp 30:1637-1651, 2009. (C) 2008 Wiley-Liss, Inc.