Popovic Z, Sjöstrand J
Department of Ophthalmology, Göteborg University, SE43180, Mölndal, Sweden.
Vision Res. 2001;41(10-11):1313-9. doi: 10.1016/s0042-6989(00)00290-x.
We present direct comparisons of resolution thresholds and quantitative estimates of retinal ganglion cell separation in humans with reported functional magnetic resonance imaging estimates of the human linear cortical magnification factor. Measurements of resolution thresholds (MAR), retinal ganglion cell (GC) densities, and linear cortical magnification factor (M) values were taken from the literature. Our objective was to analyse the apparent overrepresentation of human central vision in the visual cortex and to determine whether the cause of this is an effect of the uneven distribution of GC in the retina and/or that central GC have more devoted cortical area per cell. The reserved amount of cortical distance per retinal unit, i.e. the product of M on the one hand and effective GC separation, MAR, and GC receptive field separation on the other, indicates an overrepresentation of the fovea and immediately surrounding retina in the human striate cortex due to an increase in devoted cortical distance per central GC or resolution unit. This cannot be explained by lateral displacement of foveal ganglion cells nor by peripheral scaling, but rather by an additional magnification in the retino-cortical pathway.
我们将人类视网膜神经节细胞分离的分辨率阈值和定量估计值与已报道的人类线性皮质放大因子的功能磁共振成像估计值进行了直接比较。分辨率阈值（最小可分辨角，MAR）、视网膜神经节细胞（GC）密度和线性皮质放大因子（M）值的测量数据均取自文献。我们的目的是分析人类中央视觉在视觉皮层中明显的过度表征现象，并确定其原因是视网膜中GC分布不均的影响，还是中央GC每个细胞拥有更多专用皮质区域。每个视网膜单位保留的皮质距离量，即一方面M与另一方面有效GC分离、MAR以及GC感受野分离的乘积，表明由于每个中央GC或分辨率单位的专用皮质距离增加，人类纹状皮层中中央凹及其紧邻的视网膜存在过度表征。这既不能通过中央凹神经节细胞的横向位移来解释，也不能通过外周缩放来解释，而只能通过视网膜 - 皮质通路中的额外放大来解释。
