Behavioral, Electrophysiological and Immunohistochemical Study on the Neuronal Plasticity of the Visual System in the Rat with Monocular Enucleation

在我们的一系列行为和电生理实验中，已经证明，在出生后早期单眼去核导致扩大的非交叉视觉通路（扩大的UXVP）的同侧视觉皮层，通过背外侧膝状体核（LGNd）和通过上级丘（SC）在白化病大鼠。本研究旨在通过光栅视敏度的测定来阐明扩展的UXVP的功能，并通过c-fog免疫组化的方法来探讨扩展的UXVP的神经机制，获得了以下结果.在垂直-水平辨别学习的行为实验中，出生时单眼去核（OEB）大鼠和成熟时单眼去核（OET）大鼠UXVP的光栅视力分别为0.73周/度和0.44周/度，表明扩大的UXVP导致了OEB大鼠较高的视觉分辨能力.在免疫组化实验中，图案化的视觉刺激被用来调查的立即早期基因c-fos在胼胝体横断后的UXVP的神经元刺激依赖性诱导的可行性。将50 μ m厚的冠状切片与羊抗Fos蛋白的一级抗血清孵育，然后与生物素化的兔抗羊二级抗体孵育，并与抗生物素蛋白生物素化的辣根过氧化物酶复合物孵育。用硫酸镍铵强化DAB反应。在OEB大鼠的扩展UXVP中，在SC和视皮层（VC）的浅灰色层（SGS）中基本上检测到Fos样免疫反应（FLI）细胞，而模式化视觉刺激仅在OET大鼠的规则UXVP的SGS和VC中诱导少量FLI神经元，

In a series of our behavioral and electrophysiological experiments, it has been demonstrated that monocular enucleation in early postnatal days results in expanded uncrossed visual pathways (expanded UXVPs) to the ipsilateral visual cortex, both via the dorsal lateral geniculate nucleus (LGNd) and via the superior colliculus (SC) in the albino rat. The present study was then aimed to elucidate the function of the expanded UXVPs by evaluating the grating visual acuity and to investigate the neural mechanism of the expanded UXVPs by way of c-fog immunohistochemistry, and the following findings were obtained.1. In the behavioral experimet using a vertical-horizontal discrimination learning, the grating visual acuity of the UXVPs was 0.73 cycles/degree in the rat with monocular enucleation at birth (OEB) and 0.44 in the rat monocularly enucleated at maturity (OET), indicating that the expanded UXVPs results high visual resolution capacity in OEBs.2. In the immunohistochemical experiment, patterned visual stimulation was used to investigate the feasibility of stimulus-dependent induction of the immediate early gene c-fos in neurons of the UXVPs following callosal transection. The 50 mu m-thick coronal sections were incubated with the primary antiserum raised in sheep against the Fos protein, and then with biotinylated rabbit anti-sheep secondary antibody, and with the avidin biotinylated horseradish peroxidase complex. The DAB reaction was intensified with nickel ammonium sulfate. In the expanded UXVPs of the OEB rat, the Fos-like immunoreactive (FLI) cells were substantially detected in the stratum griseum superficiale (SGS) of the SC and the visual cortex (VC), whereas patterned visual stimulation induced only few FLI neurons in the SGS and the VC of the regular UXVPs of the OET rat,