School of Psychology, The University of New South Wales, Sydney, Australia.
J Neurophysiol. 2012 May;107(9):2570-80. doi: 10.1152/jn.00616.2011. Epub 2012 Feb 29.
A recent intrinsic signal optical imaging study in tree shrew showed, surprisingly, that the population response of V1 to plaid patterns comprising grating components of equal contrast is predicted by the average of the responses to the individual components (MacEvoy SP, Tucker TR, Fitzpatrick D. Nat Neurosci 12: 637-645, 2009). This prompted us to compare responses to plaids and gratings in human visual cortex as a function of contrast and orientation. We found that the functional MRI (fMRI) blood oxygenation level-dependent (BOLD) responses of areas V1-V3 to a plaid comprising superposed grating components of equal contrast are significantly higher than the responses to a single component. Furthermore, the orientation response profile of a plaid is poorly predicted from a linear combination of the responses to its components. Together, these results indicate that the model of MacEvoy et al. (2009) cannot, without modification, account for the fMRI BOLD response to plaids in human visual cortex.
最近一项在树鼩中进行的内源性信号光学成像研究令人惊讶地表明，V1 对由具有相同对比度的光栅成分组成的镶嵌图案的群体反应可以通过对各个成分的反应的平均值来预测 (MacEvoy SP, Tucker TR, Fitzpatrick D. Nat Neurosci 12: 637-645, 2009)。这促使我们比较了人类视觉皮层中对镶嵌图案和光栅的反应，作为对比度和方向的函数。我们发现，面积 V1-V3 的功能磁共振成像 (fMRI) 血氧水平依赖 (BOLD) 反应对由叠加的具有相同对比度的光栅组成的镶嵌图案的反应明显高于对单个成分的反应。此外，镶嵌图案的方向反应轮廓不能很好地由其组成部分的反应的线性组合来预测。综上所述，这些结果表明，MacEvoy 等人的模型 (2009 年) 不能不加修改地解释人类视觉皮层中对镶嵌图案的 fMRI BOLD 反应。
