Radial asymmetries in population receptive field size and cortical magnification factor in early visual cortex
Radial asymmetries in population receptive field size and cortical magnification factor in early visual cortex
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DOI：
10.1016/j.neuroimage.2017.11.021
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发表时间：
2018-02-15
期刊：
影响因子：
5.7
通讯作者：
Harvey, Ben M.
中科院分区：
文献类型：
--
作者：
Silva, Maria Fatima;Brascamp, Jan W.;Harvey, Ben M.
人类的视觉皮层并不代表整个视野的相同细节。接受野大小、群体接受野（pRF）大小和皮质放大因子（CMF）随偏心率的变化已得到很好的证实，并与视敏度随偏心率的变化相关。视敏度也随极角变化。然而，目前尚不清楚RF大小、pRF大小和CMF如何在极角上变化。在这里，我们研究的差异，pRF大小和CMF跨极角在V1，V2和V3使用pRF人类功能磁共振成像数据建模。在这些视野图中，我们发现水平（左和右）视野象限中的pRF较小，CMF较大，而垂直（上和下）视野象限中的pRF较小，CMF较大。差异随着偏心率的增加而增加，大约与平均pRF大小和CMF成比例。同样，我们发现在下象限中的CMF大于上象限，并且差异再次随着偏心率而增加。然而，下象限和上象限之间的pRF尺寸差异会随着偏心率而改变方向。最后，我们发现V2和V3的左象限比右象限的pRF略小，尽管这种差异非常小，我们发现V1和CMF没有差异。此外，pRF大小和CMF的差异随着极角逐渐变化，并且不限于子午线或视野图不连续性。尽管V1中皮质曲率和极角之间存在联系，但PRF大小和CMF差异并不一致地遵循皮质曲率模式。因此，早期人类视觉皮层具有视野的径向不对称表示。这些不对称性可能是感知能力不对称性的一致报告的基础。
Human visual cortex does not represent the whole visual field with the same detail. Changes in receptive field size, population receptive field (pRF) size and cortical magnification factor (CMF) with eccentricity are well established, and associated with changes in visual acuity with eccentricity. Visual acuity also changes across polar angle. However, it remains unclear how RF size, pRF size and CMF change across polar angle. Here, we examine differences in pRF size and CMF across polar angle in V1, V2 and V3 using pRF modeling of human fMRI data. In these visual field maps, we find smaller pRFs and larger CMFs in horizontal (left and right) than vertical (upper and lower) visual field quadrants. Differences increase with eccentricity, approximately in proportion to average pRF size and CMF. Similarly, we find larger CMFs in the lower than upper quadrant, and again differences increase with eccentricity. However, pRF size differences between lower and upper quadrants change direction with eccentricity. Finally, we find slightly smaller pRFs in the left than right quadrants of V2 and V3, though this difference is very small, and we find no differences in V1 and no differences in CMF. Moreover, differences in pRF size and CMF vary gradually with polar angle and are not limited to the meridians or visual field map discontinuities. PRF size and CMF differences do not consistently follow patterns of cortical curvature, despite the link between cortical curvature and polar angle in V1. Thus, the early human visual cortex has a radially asymmetric representation of the visual field. These asymmetries may underlie consistent reports of asymmetries in perceptual abilities.