PLASTICITY OF THE DEVELOPING MAMMALIAN VISUAL SYSTEM

1)永久性异位视网膜向听觉或体感的投射 叙利亚新生儿的神经外科手术可以可靠地产生丘脑核团 仓鼠。神经生理记录与2-脱氧葡萄糖代谢 将使用测绘技术来确定异常投影是否 驱动丘脑神经元或丘脑的皮质神经元 神经元投射。单个神经元的感受野特性 接收异常视觉输入和视网膜组织 还将对异位视觉通路进行电生理学研究。 异位投射的发展将用顺行性研究。 运输技术。这些研究的结果具有根本性的 对有序连接和单一单元发展的影响 在正常动物中的感受野特性，并在 人类中枢神经系统损害的治疗。 2)视束和二级躯体感觉通路再生。 新生仓鼠的横断体。酶和蛋白质的逆行转运 将使用荧光示踪剂来确定这种再生是否是由于 对切断轴突的再生还是对后期发育的未切断轴突的生长 横断水平的轴突。再生长的时间进程 还将接受检查。这些研究将有助于确定 横断的中枢神经系统轴突可以再生的情况 对中枢神经系统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.