ROLE OF ACTION POTENTIALS IN VISUAL SYSTEM DEVELOPMENT

本项目旨在确定动作电位的作用 在视觉系统中正常突触连接的发展中的活动 系统 所用的实验动物是新生小猫。 行动 通过重复注射河豚毒素（TTX） 一只眼睛 这种封锁是可逆的;当它被允许磨损时， 视网膜神经节细胞与外侧膝状体的联系 (LGN)评估中继单元。 单单位电生理记录 技术是表征感受野的主要手段 LGN神经元的特性。 我们已经确定， 封锁造成许多不分青红皂白的联系， 沉默的视网膜轴突和LGN中继细胞。 例如，完全不正常 ON/OFF型中继单元在被剥夺的LGN层中占大多数。 这是对正常发展的严重破坏。 而且很多 双眼神经支配单位位于正常和 剥夺LGN层。 这是第一次证明神经细胞 活动本身是决定神经相互联系的一个因素 在视觉系统中。 这里提出的工作有两个主要目标：1。到 进一步表征视觉上动作电位缺失的结果， 系统开发; 2.试图理解 动作电位活动影响正确的突触发育。

This project is directed at determining the role of action potential activity in the development of proper synaptic connections in the visual system. The experimental animal used is the newborn kitten. Action potentials are silenced by repeated injection of tetrodotoxin (TTX) into one eye. This blockade is reversible; when it is allowed to wear off, connections between retinal ganglion cells and lateral geniculate nucleus (LGN) relay cells are assessed. Single unit electrophysiological recording techniques are the major means used to characterize receptive field properties of LGN neurons. We have already determined that prolonged TTX blockade causes many indiscriminate connections to be made between the silenced retinal axons and LGN relay cells. For example, totally abnormal ON/OFF type relay cells are in the majority in the deprived LGN layers. This represents a gross disruption of normal development. Also, many binocularly innervated units are found at the borders on normal and deprived LGN layers. This is the first demonstration that nerve cell activity, per se, is a factor in determination of neural interconnections in the visual system. The work proposed here has two main aims: 1. to further characterize the results of action potential absence on visual system development; 2. to attempt to understand the mechanism by which action potential activity influences proper synaptic development.