Postnatal development of binocular disparity sensitivity in neurons of the primate visual cortex
Postnatal development of binocular disparity sensitivity in neurons of the primate visual cortex
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DOI：
10.1523/jneurosci.17-01-00296.1997
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发表时间：
1997-01-01
影响因子：
5.3
通讯作者：
Cheng, H
中科院分区：
文献类型：
--
作者：
Chino, YM;Smith, EL;Cheng, H
在猕猴中，初级视觉皮层（V1）的神经元对两眼间图像差异（立体视觉的先决条件）变得敏感的年龄是一个推测问题。为了解决这一根本问题，在双眼视觉的发展，我们测量了个别V1神经元麻醉和瘫痪的婴儿猴的相对，眼间，空间相位的dichoptic正弦波光栅的功能。我们发现，一个成年人一样的单位比例是敏感的眼间图像差异，早在出生后第六天，几个星期前的发病年龄的立体视觉猴子。幼猴的眼优势细胞分布与成年猴的眼优势细胞分布也没有区别。因此，在出生后或仅出生后几天，V1神经元能够像成年人一样组合来自两只眼睛的神经信号，并且对眼间图像差异敏感。然而，这些视觉敏感单位的单眼空间频率响应特性是不成熟的，他们的整体反应性远低于成人。在出生后的前4周内，空间频率响应特性和峰值响应幅度迅速改善，这导致个体单位对眼间视差的绝对敏感性相应增加。结果表明，猴子的早期双眼视觉发育并不受缺乏对视觉敏感的V1神经元的限制，而是受空间响应特性的相对不成熟和现有对视觉敏感的神经元的整体无反应性的限制。
In macaque monkeys, the age at which neurons in the primary visual cortex (V1) become sensitive to interocular image disparities, a prerequisite for stereopsis, is a matter of conjecture. To resolve this fundamental issue in binocular vision development, we measured the responsiveness of individual V1 neurons in anesthetized and paralyzed infant monkeys as a function of the relative, interocular, spatial phase of dichoptic sine-wave gratings. We found that an adult-like proportion of units were sensitive to interocular image disparity as early as the sixth postnatal day, several weeks before the onset age for stereopsis in monkeys. The ocular dominance distributions of cells in infant monkeys were also indistinguishable from those of adults. Thus, at or only a few days after birth, V1 neurons are capable of combining neural signals from the two eyes as in adults and are sensitive to interocular image disparities. However, the monocular spatial-frequency response properties of these disparity-sensitive units were immature, and their overall responsiveness was far lower than that in adults. During the first 4 postnatal weeks, both the spatial frequency response properties and the peak response amplitude rapidly improved, which resulted in a corresponding increase in the absolute sensitivity of individual units to interocular disparity. The results demonstrate that early binocular vision development in monkeys is not constrained by a paucity of disparity-sensitive V1 neurons but, instead, by the relative immaturity of the spatial response properties and the overall unresponsiveness of existing disparity-sensitive neurons.