Molecular and cellular mechanisms of defective neural network rhythm generation

本课题以自发突变型神经系统小鼠为研究对象，分析了癫痫和小脑共济失调等神经系统症状背后的海马、丘脑、大脑皮层和小脑皮层的网络机制，发现癫痫钙通道突变型小鼠“蹒跚”的丘脑皮层投射前馈回路存在缺陷。我们证明了突触传递的缺陷以发育依赖的方式出现。我们尝试用多电极细胞外记录系统检测癫痫样放电，但未能获得稳定一致的结果。因为很难理解局部网络的活动，我们开始进行双倍和三倍膜片钳记录。利用这个先进的系统，我们阐明了丘脑神经元同步活动所需的基本神经布线模式（手稿正在准备中）。我们还对钙通道突变的形态学影响感兴趣。我们使用浦肯野神经元的逆行标记，并开发分析软件来定量测量浦肯野细胞树突状乔木的领土和分支。除了体外脑切片记录外，还必须记录体内神经活动。我们开发了一个用于体内记录的系统。我们现在正在对正常小鼠和突变小鼠进行比较。

In this project, we mainly tried to analyze network mechanisms in the hippocampus, thalamus, cerebral cortex and cerebellar cortex, which underlie neurological symptoms such as epilepsy and cerebellar ataxia, using spontaneous mutant neurological mice.We identified a defect in the feedforward circuit of the thalamocortical projection in epileptic calcium channel mutant mice 'tottering'. We demonstrated the defect of synaptic transmission appears in a development-dependent manner. We tried to detect epileptiform discharges using a multi-electrode extracellular recording system, but we failed to obtain stable and consistent results.Until recently, patch clamp recordings from brain slice preparations are mostly from single neurons. Because it is difficult to understand activity of the local network, we started to double- and triple-patch clamp recordings. With this advanced system, we elucidated the basic neural wiring pattern that is required for synchronized activity of thalamic neurons (manuscript in preparation).We were also interested in the morphological impacts of calcium channel mutations. We used retrograde labeling of Purkinje neurons, and developed analysis software to quantitatively measure the territory and branching of Purkinje cell dendritic arbors. In addition to in vitro brain slice recordings, it is essential to record neural activity in vivo. We developed a system for in vivo recording. We are now making comparison between normal and mutant mice.