Organization of Auditory Thalamocortical Pathways

这些实验的长期目标是确定初级听觉皮层（AI）的功能特性与内侧膝状体（MGV）腹侧部产生的斑片状丘脑皮质投射之间的相关性。与其他感觉系统不同，辅助功能地图AI的丘脑皮质通路并没有很好地定义。一个补丁或不连续的组织功能特性存在于AI的几个物种。MGB腹侧部向AI的投射也呈斑片状或不连续。此外，MGV内投射到AI的两个主要区域（pars lateralis和pars ovoidea）已经通过细胞结构、功能特性和免疫细胞化学进行了区分，并且有证据表明存在从MGV到AI的多个平行途径。这些多个途径可以编码不同的功能特性。在具体目标1中，我们将确定从MGV到AI和AI中的功能反应簇产生的斑块状TC投影之间的关系。在具体目标2中，我们将描述LV和OV对AI的TC投射，以确定它们是否以独特的方式投射到AI，并产生新的功能特性类别。BDA注射将专门针对IV和OV。在具体目标3中，我们将表征和比较MGV中的TC投影模式单个、完全重建的中继细胞。拟议的研究将定义AI中存在的功能特性的解剖学基底，并表征从MGV到AI的多个并行电路。

The long term goal of these experiments is to define the correlation between functional properties in primary auditory cortex (AI) and the patchy thalamocortical projections that arise from the ventral division of the medial geniculate body (MGV). Unlike other sensory systems, the thalamocortical pathways that subserve functional maps AI are not well defined. A patchy or discontinuous organization of functional properties exists in AI of several species. There also exists a patchy or discontinuous thalamocortical projection pattern from the ventral division of the MGB to AI. Further, two major areas (pars lateralis and pars ovoidea) within the MGV that project to AI have been differentiated by cellular architecture, functional properties and immunocytochemistry, and there is evidence to suggest the existence of multiple parallel pathways from MGV to AI. These multiple pathways may encode different functional properties. In specific aim 1 we will determine the relationship between patchy TC projections arising from MGV to AI and functional response clusters in AI. In specific aim 2 we will characterize TC projections to AI arising from the LV and OV to determine if they project in a unique way to AI and give rise to novel classes of functional properties. BDA injections will target the IV and OV specifically. In specific aim 3 we will characterize and compare the TC projection patterns single, fully reconstructed relay cells in the MGV. The proposed studies will define the anatomical substrates for functional properties that exist in AI and characterize multiple parallel circuits from MGV to AI.