DEVELOPMENTOF THE MAMMALIAN VISUAL SYSTEM

1)永久性异位视网膜投射至听觉或躯体感觉 丘脑核可以通过神经外科手术可靠地产生新生叙利亚人 仓鼠 神经生理记录与2-脱氧葡萄糖代谢 测绘技术将用于确定是否异常投影 驱动丘脑神经元或皮层神经元， 神经元项目。 单个神经元的感受野特性 接收所述异常视觉输入和所述视网膜的视网膜定位结构， 还将对异位视觉通路进行电生理学研究。 异位投射的发育将通过顺行性 运输技术。 这些研究的结果具有基础性 对有序连接和单个单元发展的影响 正常动物的感受野特性， 治疗人的中枢神经系统（CNS）损伤。 2)视束和第二级躯体感觉通路再生， 新生仓鼠的横切。 逆行转运酶和 荧光示踪剂将用于确定这种再生是否是由于 切断轴突的再生或未切断的晚期发育的轴突的生长 轴突，穿过横切平面。 再生的时间过程 也将被审查。 这些研究将有助于确定 在这种情况下，切断的CNS轴突可以再生;这是 对CNS创伤性损伤的临床治疗具有重要意义。

1) Permanent ectopic retinal projections to auditory or somatosensory thalamic nuclei can be reliably produced by neurosurgery on newborn Syrian hamsters. Neurophysiological recording and the 2-deoxyglucose metabolic mapping techniques will be used to determine if the anomalous projections drive thalamic neurons or the cortical neurons to which the thalamic neurons project. The receptive field properties of single neurons receiving the anomalous visual input and the retinotopic organization of the ectopic visual pathways will also be studied electrophysiologically. The development of the ectopic projections will be studied by anterograde transport techniques. The results of these studies have fundamental implications for the development of orderly connections and single unit receptive field properties in normal animals and are of potential value in the treatment of central nervous system (CNS) lesions in man. 2) The optic tract and second order somatosensory pathways regrow following transection in neonatal hamsters. Retrograde transport of enzymatic and fluorescent tracers will be used to determine whether this regrowth is due to regeneration of cut axons or to the growth of late-developing uncut axons, across the level of transection. The time course of the regrowth will also be examined. These studies will help to determine the circumstances under which transected CNS axons can regenerate; this is important for the clinical treatment of traumatic injury of the CNS.