ROLE OF ACTION POTENTIALS IN VISUAL SYSTEM DEVELOPMENT

该项目旨在确定动作电位的作用。 视觉中适当突触连接发育中的活动 系统。使用的实验动物是刚出生的小猫。行动 反复向脑内注射河豚毒素(TTX)可使电位沉默 一只眼睛。这种封锁是可逆的；当它被允许消失时， 视网膜神经节细胞与外侧膝状体核的联系 (LGN)中继信元被评估。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。我们已经确定延长的TTX 封锁导致许多不分青红皂白的联系在 静默的视网膜轴突和LGN中继细胞。例如，完全不正常 在被剥夺的LGN层中，开/关型中继小区占大多数。 这是对正常发展的严重破坏。此外，还有许多 双目神经支配单位出现在正常和正常的交界处 剥夺了LGN层。这是第一次证明神经细胞 活动性本身是决定神经互连的一个因素。 在视觉系统中。这里提出的工作有两个主要目的：1. 进一步表征动作电位缺失对视觉的影响 系统开发；2.试图了解通过什么机制 动作电位活动影响突触的正常发育。

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.