DEVELOPMENT OF THE CALYX OF HELD

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 Hold可能是哺乳动物大脑中最大的突触终末，我们先前已经证实，Hold的花冠生长发生在出生后2天到4天的48小时内。这些终末生长在听性脑干的斜方体内侧核(MNTB)的主要神经元的胞体上并覆盖其大部分。花萼的生长需要巨大的细胞资源，才能实现末端的形态扩张和数百个活动区的建立。在这个过程中，许多汇聚的突触前输入中只有一个会生长并形成花萼末端，从而迅速建立1：1神经支配，这种神经在感觉输入被检测到并通过这个回路传输之前就一直持续到成年期。 我们的长期目标是揭示结构转换和细胞通讯，这些结构和细胞通讯表征了成杯生长锥与其目标的接触，以及听觉脑干中大型神经末梢的突触组装和稳定的早期阶段。我们的中心假设是，在末端在细胞体上扩张以形成花萼之前，发生花丝的输入之间的竞争。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We have previously established that growth of the calyx of Held, perhaps the largest synaptic terminal in the mammalian brain, occurs over a 48 hour period from postnatal day (P) 2 to P4. These terminals grow onto and cover large portions of the somata of principal neurons in medial nucleus of the trapezoid body (MNTB) in the auditory brainstem. Calyx growth requires tremendous cellular resources to achieve the morphological expansion of the terminals and the establishment of hundreds of active zones. During this process, only one of many converging presynaptic inputs will grow and form a calyx terminal, and thus rapidly establish 1:1 innervation that persists through adulthood, well before sensory input is detected and transmitted through this circuit. Our long-range goal is to reveal structural transformations and cellular communication that characterize contact of the calycigenic growth cone with its target and the early stages of synapse assembly and stabilization at large nerve terminals in the auditory brainstem. Our central hypothesis is that competition among calycigenic inputs precedes expansion of the terminal over the cell body to form a calyx.