HUMAN PERIPHERAL SPATIAL-RESOLUTION FOR ACHROMATIC AND CHROMATIC STIMULI - LIMITS IMPOSED BY OPTICAL AND RETINAL FACTORS
HUMAN PERIPHERAL SPATIAL-RESOLUTION FOR ACHROMATIC AND CHROMATIC STIMULI - LIMITS IMPOSED BY OPTICAL AND RETINAL FACTORS
复制标题
DOI：
10.1113/jphysiol.1991.sp018781
复制
发表时间：
1991-10-01
影响因子：
5.5
通讯作者：
HESS, RF
中科院分区：
文献类型：
--
作者：
ANDERSON, SJ;MULLEN, KT;HESS, RF
1. 本研究的目的是确定是否光学，感受器或高阶神经特性限制人类视觉的空间分辨率（敏锐度），特别是在视野的周边区域。 消色差和彩色刺激，并采取措施，以确保分辨率估计不受污染的检测空间采样文物。 空间对比敏感度函数在视网膜位置从0度到55度沿着鼻颞子午线测量：（i）辨别在8 Hz漂移的亮度调制（黑白）正弦刺激的漂移方向（消色差任务）;和（ii）用于检测在0.4 Hz漂移的等亮度红绿正弦刺激（彩色任务）。 无色对比敏感度函数也被测量沿着垂直子午线的偏心率为8和40度。 将每个消色差函数外推到对比敏感度为1（100%对比度），以估计消色差敏锐度。 通过用视锥对比度表示色彩对比度并使用相同的外推方法获得色彩锐度。 我们将结果与最近的人类光学特性和视网膜解剖学数据进行了比较。 消色差和彩色敏锐度都随着距中央凹的距离而下降，但下降的速度比人眼的已知光学和/或感受器特性所指示的速度更快。 我们的结论是，无论是无色或彩色对比度的刺激，外周空间分辨率是有限的后受体机制。 此外，色度敏锐度下降更陡峭比亮度敏锐度与偏心率表明，有额外的post-receptoral限制在外围的颜色分辨率。 一个明确的鼻颞不对称性被认为是在分辨率的依赖性是定性的，但不是定量的，类似的奈奎斯特限制所施加的不对称密度的人视网膜神经节细胞。 我们讨论的可能性，在周边视觉（超越视神经乳头）的神经节细胞的间距可能会造成一个根本的限制，对决议的非彩色刺激，但不是彩色刺激。
1. The aim of this study was to determine whether optical, receptoral or higher-order neural properties limit spatial resolution (acuity) in human vision, especially in the peripheral regions of the visual field.2. Both achromatic and chromatic stimuli were used, and measures were taken to ensure that the resolution estimates were not contaminated by the detection of spatial sampling artifacts. Spatial contrast sensitivity functions were measured at retinal locations from 0 to 55 deg along the naso-temporal meridian for: (i) discriminating the direction of drift of luminance-modulated (black-white) sinusoidal stimuli drifting at 8 Hz (achromatic task); and (ii) for detecting isoluminant red-green sinusoidal stimuli drifting at 0.4 Hz (chromatic task). Achromatic contrast sensitivity functions were also measured along the vertical meridian for eccentricities of 8 and 40 deg. Each achromatic function was extrapolated to a contrast sensitivity of one (100 % contrast) to estimate achromatic acuity. Chromatic acuities were obtained by expressing chromatic contrast in terms of cone contrasts and using the same method of extrapolation. We compared the results with recent data on human optical properties and retinal anatomy.3. Both achromatic and chromatic acuity decline with distance from the fovea, but at a faster rate than that dictated by the known optical and/or receptoral properties of the human eye. We conclude that, for stimuli of either achromatic or chromatic contrast, peripheral spatial resolution is limited by post-receptoral mechanisms. Also, chromatic acuity declines more steeply than luminance acuity with eccentricity suggesting that there are additional post-receptoral limitations on colour resolution in the periphery.4. A clear naso-temporal asymmetry is seen in the resolution whose dependence is qualitatively, but not quantitatively, similar to the Nyquist limits imposed by the asymmetric density of human retinal ganglion cells. We discuss the possibility that in peripheral vision (beyond the optic nerve head) the spacing of ganglion cells may pose a fundamental limit on the resolution of achromatic stimuli, but not chromatic stimuli.