Crossed-uncrossed projections from primate retina are adapted to disparities of natural scenes
Crossed-uncrossed projections from primate retina are adapted to disparities of natural scenes
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DOI：
10.1073/pnas.2015651118
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发表时间：
2021-02-16
影响因子：
11.1
通讯作者：
Banks, Martin S.
中科院分区：
文献类型：
--
作者：
Gibaldi, Agostino;Benson, Noah C.;Banks, Martin S.
在有额眼的哺乳动物中，鼻侧视网膜的视神经纤维投射到大脑的对侧半球，颞侧视网膜的纤维投射到同侧。交叉投影和非交叉投影之间的划分发生在垂直子午线处或附近。如果划分得很精确，就会出现问题。靠近中线但比当前注视更近或更远的小物体会产生传播到相对半球的信号，使得这些物体的双眼视差难以计算。然而，在已经研究过的物种中，这种划分并不精确。相反，存在重叠的交叉和非交叉投影，使得来自鼻侧视网膜的一些纤维投影同侧以及对侧，并且来自颞侧视网膜的一些纤维投影对侧以及同侧。这增加了来自垂直中线附近的对象的信号传播到同一半球的概率，从而有助于视差估计。我们调查了人类垂直子午线附近的双眼视觉是否存在缺陷，但没有发现证据。我们还研究了观察到的交叉模式的有效性，从猴子和人类的解剖数据量化。我们使用测量人类自然发生的差异，以确定整个视野的差异分布。然后，我们使用这些分布来计算传输到同一半球的自然视差的概率，从而帮助视差计算。我们发现重叠投影的模式是相当有效的。因此，来自视网膜的交叉和非交叉投影被很好地设计用于辅助视差估计和立体视觉。
In mammals with frontal eyes, optic-nerve fibers from nasal retina project to the contralateral hemisphere of the brain, and fibers from temporal retina project ipsilaterally. The division between crossed and uncrossed projections occurs at or near the vertical meridian. If the division was precise, a problem would arise. Small objects near midline, but nearer or farther than current fixation, would produce signals that travel to opposite hemispheres, making the binocular disparity of those objects difficult to compute. However, in species that have been studied, the division is not precise. Rather, there are overlapping crossed and uncrossed projections such that some fibers from nasal retina project ipsilaterally as well as contralaterally and some from temporal retina project contralaterally as well as ipsilaterally. This increases the probability that signals from an object near vertical midline travel to the same hemisphere, thereby aiding disparity estimation. We investigated whether there is a deficit in binocular vision near the vertical meridian in humans and found no evidence for one. We also investigated the effectiveness of the observed decussation pattern, quantified from anatomical data in monkeys and humans. We used measurements of naturally occurring disparities in humans to determine disparity distributions across the visual field. We then used those distributions to calculate the probability of natural disparities transmitting to the same hemisphere, thereby aiding disparity computation. We found that the pattern of overlapping projections is quite effective. Thus, crossed and uncrossed projections from the retinas are well designed for aiding disparity estimation and stereopsis.