Spatial interaction in the human retina during scotopic vision.
Spatial interaction in the human retina during scotopic vision.
复制标题
暗视觉期间人类视网膜的空间相互作用。
DOI：
--
复制
发表时间：
1965
期刊：
影响因子：
--
通讯作者：
G. Westheimer
中科院分区：
文献类型：
--
作者：
G. Westheimer
眼睛对光的敏感度随着背景亮度的增加而降低。人们曾经认为，这可以简单地解释为受体中可用的光敏色素储存库的减少，但最近的测量表明，灵敏度的变化太大，无法用一个涉及视觉色素浓度的简单理论来解释。眼睛检测亮度差异的性能限制是由量子可变性设定的；但是这个理论极限的存在告诉我们眼睛在区分亮度差异方面能做得多好，而不是它实际上是如何做到的。即使是将单个光感受器的化学、结构或功能变化与其灵敏度联系起来的非常详尽的理论，也不能完全涵盖这一领域的所有已知现象。这尤其适用于相邻区域的空间相互作用，这一相互作用长期以来一直被认为有助于观察到的一些视网膜功能现象。因此，在黑暗适应中，当大区域或小区域受到刺激时，人类视杆视网膜绝对灵敏度的变化以不同的速度进行（Craik & Vernon, 1941; Arden & Weale, 1954），并且有证据表明发生了来自受体的广泛信号汇集（Rushton & Westheimer, 1962; Rushton, 1965）。对视网膜神经节细胞接受野的电生理学研究（Hartline, 1940）使我们熟悉了池的概念，Barlow， FitzHugh和Kuffler（1957）的发现表明，这些池的性质可能在适应过程中发生变化。早期的理论分析（Broca, 1901; Lythgoe, 1940; Craik & Vernon, 1941; Pirenne & Denton, 1952）试图通过假设视网膜中求和区的变化来解释各种适应现象，但Barlow等人的研究清楚地表明，这种求和可能涉及兴奋和抑制信号。电生理实验的一个基本优点是，它们可以显示视网膜中单个神经节细胞的兴奋和抑制的汇合，并允许得出这样的结论：落在给定空间区域的光对该神经节细胞起兴奋或抑制作用
The eye's sensitivity to light decreases with increasing background luminances. It was once thought that this could be simply explained by the decrease in the reservoir of available photolabile pigments in the receptors, but recent measurements have shown that changes in sensitivity are far too large to be accounted for by a simple theory involving concentration of visual pigments. A limit to the performance of the eye in detecting differences in brightness is set by quantum variability; but this existence of a theoretical limit tells us how well the eye could do in distinguishing brightness differences, not how it in fact achieves this. Even quite elaborate theories relating chemical, structural or functional changes in the individual light receptors to their sensitivity cannot fully encompass all known phenomena in this field. This applies particularly to the spatial interaction of adjoining regions which has been known for a long time to be contributing to some of the observed phenomena of retinal function. Thus in dark adaptation the changes in the absolute sensitivity of the human rod retina proceed at different rates when large or small areas are stimulated (Craik & Vernon, 1941; Arden & Weale, 1954), and there is evidence that extensive pooling of signals from receptors takes place (Rushton & Westheimer, 1962; Rushton, 1965). Electrophysiological work on receptive fields of retinal ganglion cells (Hartline, 1940) has made us familiar with the concept of pooling, and the findings of Barlow, FitzHugh & Kuffler (1957) show that the nature of these pools may change during adaptation. Earlier theoretical analyses (Broca, 1901; Lythgoe, 1940; Craik & Vernon, 1941; Pirenne & Denton, 1952) had sought to account for various adaptational phenomena by postulating changes in summation areas in the retina, but the studies of Barlow et al. make clear that such summation may involve both excitatory and inhibitory signals. A basic merit of the electrophysiological experiments is that they can show the confluence of excitation and inhibition on a single ganglion cell in the retina and permit the conclusion that light falling on a given spatial region acts in an excitatory or inhibitory capacity on that ganglion cell