DEVELOPMENTAL STUDIES OF THE VISUAL SYSTEM

这里提出的研究将调查出生后 猫视网膜-膝状体-皮质通路的发育。 描述了四组实验：(1)常规实验和视觉实验 剥夺猫背部环路的结构发育 外侧膝状体(LGN)和初级视皮层(区 17)被认为使用伽马氨基丁酸(GABA)作为 神经递质将用光和电子来研究 显微免疫细胞化学，使用制备的特定抗体 反对GABA。(2)替代电力的效果 刺激视网膜神经节细胞(RGC)动作电位 视网膜原性突触的形态发育将是 眼内注射阿司匹林饲养猫的效果观察 河豚毒素(TTX)，以取消RGC动作电位，而 用植入的电极刺激视束。在……里面 此外，GABA阳性神经元和终末的发育 在LGN和第17区也将对注射TTX的猫进行研究 采用光镜和电子显微镜免疫细胞化学方法。(3) 视网膜神经节细胞生理分类的形态观察 成年猫受到视皮层的大损伤(17区， 18和19)出生的时间将由直接细胞内决定 辣根过氧化物酶标记单个神经节细胞 (HRP)。(4)正常和贫困儿童的突触组织 膝状体皮质轴突将通过结合电子来澄清 细胞内注射HRP的显微镜观察 生理鉴定的膝皮质纤维。 这项研究的长期目标是进一步推动我们的 对视觉系统后天发育的理解 在正常和非正常情况下。特别令人感兴趣的是： (A)有模式的冲动活动在 视网膜-膝状体-皮质通路的形态发育； 和(B)允许补偿性重组的因素 早期病变后的中枢视觉通路。其用意是 这项工作将有助于阐明 弱视的影响或因损害而导致的后遗症 中央视觉结构。

The research proposed here will investigate the postnatal development of the retino-geniculo-cortical pathway in the cat. Four sets of experiments are described: (1) In normal and visually deprived cats, the structural development of circuits in the dorsal lateral geniculate nucleus (LGN) and primary visual cortex (area 17) that are thought to use gamma-aminobutyric acid (GABA) as a neurotransmitter will be studied with light and electron microscopic immunocytochemistry, using specific antibodies made against GABA. (2) The effect of substituting electrical stimulation for retinal ganglion cell (RGC) action potentials on the morphological development of retinogeniculate synapses will be investigated by rearing cats with intraocular injection of tetrodotoxin (TTX), to abolish RGC action potentials, while stimulating the optic tract with implanted electrodes. In addition, the development of GABA-positive neurons and terminals in the LGN and area 17 will also be studies in TTX-injected cats using light and electron microscopic immunocytochemistry. (3) The morphology of physiologically classified retinal ganglion cells in adult cats that received a large lesion of visual cortex (areas 17, 18, and 19) at birth will be determined by direct intracellular labeling of single ganglion cells with horseradish peroxidase (HRP). (4) The synaptic organization of normal and deprived geniculocortical axons will be clarified by combining electron microscopy with the intracellular injection of HRP into physiologically identified geniculocortical fibers. The long-term objective of this research is to further our understanding of the postnatal development of the visual system under normal and abnormal conditions. Of particular interest is: (a) the role played by patterned impulse activity in the morphological development of the retino-geniculo-cortical pathway; and (b) the factors that permit compensatory reorganization in the central visual pathway after early lesions. It is intended that this work will shed light on the mechanisms that contribute to the effects of amblyopia or the sequelae that result from damage to central visual structures.