Similar spatial patterns of neural coding of category selectivity in FFA and VWFA under different attention conditions
Similar spatial patterns of neural coding of category selectivity in FFA and VWFA under different attention conditions
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DOI：
10.1016/j.neuropsychologia.2012.01.026
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发表时间：
2012-04
期刊：
影响因子：
2.6
通讯作者：
Guangliang Xu;Yi Jiang;Lifei Ma;Zhi Yang;X. Weng
中科院分区：
文献类型：
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作者：
Guangliang Xu;Yi Jiang;Lifei Ma;Zhi Yang;X. Weng
长期以来，人们一直在争论注意力是否会改变梭形脸区域(FFA)和视觉词形区域(VWFA)等区域的范畴选择性。我们通过研究在不同的注意条件下，这些区域中某些刺激类别的神经表征的空间模式是否会改变来解决这个问题。面孔、汉字和纹理被呈现在区组设计的fMRI实验中，不同跑步的参与者在不同的注意条件下注意刺激。在使用一般线性模型定位了FFA和VWFA中的感兴趣区(ROI)之后，我们执行了空间模式分析来检验这些ROI中的条件内分类和交叉条件分类。条件内结果重复了先前的发现，即当注意力较少时，与注意力较多时相比，分类准确率显著降低。关键是，FFA和VWFA的交叉条件分类都显示了所有刺激类别的显著高于机会的准确性，这表明在不同的注意条件下，空间神经表征相似。进一步证实了这一结论，当调整信号的对比度噪声比(CNR)以增加信号强度时，FFA中的人脸和VWFA中的汉字的交叉条件分类精度显著提高，甚至接近条件内分类精度。这表明注意并不调节涉及类别选择性的神经表征的空间模式，而只是改变相对于噪声水平的信号强度。
It has long been debated whether attention alters the categorical selectivity in regions such as the fusiform face area (FFA) and the visual word form area (VWFA). We addressed this issue by examining whether the spatial pattern of neural representations for certain stimulus categories in these regions would change under different attention conditions. Faces, Chinese characters, and textures were presented in a block design fMRI experiment where participants in different runs attended to the stimuli under different conditions of attention. After localizing regions of interest (ROIs) in FFA and VWFA using general linear models, we performed spatial pattern analyses to examine both within- and cross-condition classification in these ROIs. The within-condition results replicated previous findings showing significant classification accuracy reduction when there was less attention compared with more attention. Critically, cross-condition classification in both FFA and VWFA revealed significantly above-chance accuracy for all stimulus categories, suggesting similar spatial neural representations across different attention conditions. Further strengthening this conclusion, when the contrast-to-noise ratio (CNR) of the signals was adjusted to increase signal strength, cross-condition classification accuracy for faces in FFA and for Chinese characters in VWFA improved significantly, even approaching within-condition accuracy. This indicates that attention does not modulate the spatial pattern of neural representations involved in category selectivity, but only changes the signal strength relative to the noise level.