HEARING: DEVELOPMENT OF SYNAPTIC CIRCUITS

描述：本应用程序将研究提升的发展 终止于下丘内的非重叠或 仅部分重叠的带状和斑块图案。传入带 终止代表了整个厚度的垂直偏析 下丘的纤维树突层和斑块代表 沿层平面的水平偏析。尚不清楚是否 这些模式是在传入纤维首先进入下层时建立的 丘或它们是否从最初的重叠中二次形成。 尽管如此，这些传入模式以及平行的纤维树突 下丘的结构，确定突触相互作用 发生在细胞核内。为了了解神经回路如何 涉及信息处理的发展，拟议的研究将确定 1）到达、分布和时空特征 传入预测的细化，2）这些事件与 突触发生和 3) 控制模式形成的机制 各层内的传入终止。具体来说，实验将 通过研究上升预测的发展来解决这些问题 从外侧上橄榄 (LSO) 和背侧到下丘 晚熟哺乳动物雪貂的外侧丘系核（DNLL）。的 LSO 和 DNLL 轴突向下投射的位置和分布 将在雪貂套件的正常发育系列中研究丘 耳蜗消融实验系列。亲脂性碳花青染料， DiI 和 DiD，将用于标记同侧和对侧 LSO 和 DNLL 纤维的连合处。此外，突触的分布 沿着音调轴并平行于纤维树突层的接触 将在追踪确定的发育时间点采样 研究。了解对下等人的传入投射的发展 丘以及最终产生的集成电路对于 了解可能因遗传异常而面临风险的听觉功能， 营养不平衡、怀孕期间致畸剂的影响甚至可能 到早产。虽然随后的听觉体验可能会改变内在的 听觉回路，功能回路的初始构造仍然存在 理解神经和行为可塑性的基础，这可能会导致 合理干预和治疗结果。

DESCRIPTION: The present application will study development of ascending projections that terminate within the inferior colliculus in non-overlapping or only partially overlapping patterns of bands and patches. Bands of afferent termination represent a vertical segregation across the thickness of the fibrodendritic layers of the inferior colliculus and patches represent a horizontal segregation along the plane of the layers. It is not known whether these patterns are established as the afferent fibers first enter the inferior colliculus or whether they form secondarily from an initial overlap. Nevertheless these afferent patterns, together with the parallel fibrodendritic architecture of the inferior colliculus, determine the synaptic interactions that take place within the nucleus. In order to understand how neural circuits involved in information processing develop, the proposed studies will identify 1) the spatial and temporal characteristics of arrival, distribution and refinement of afferent projections, 2) the relationship of those events to synaptogenesis and 3) the mechanisms that govern the formation of the pattern of afferent termination within the layers. Specifically, experiments will address these issues by studying the development of the ascending projections to the inferior colliculus from the lateral superior olive (LSO) and dorsal nucleus of the lateral lemniscus (DNLL) in an altricial mammal, the ferret. The position and distribution of the LSO and DNLL axons projecting to the inferior colliculus will be studied in a normal developmental series of ferret kits and an experimental series with cochlear ablations. Lipophilic carbocyanine dyes, DiI and DiD, will be used to label the ipsilateral and contralateral LSO and the commissure of DNLL fibers. In addition, the distribution of synaptic contacts along the tonotopic axis and parallel to the fibrodendritic layers will be sampled at developmental time points determined from the tracing studies. Knowledge of the development of afferent projections to the inferior colliculus, and the integrative circuits that ultimately result, is critical in understanding auditory functions that may be at risk due to genetic anomaly, nutritional imbalance, effects of teratogens during pregnancy or perhaps even to premature birth. While subsequent auditory experience may alter intrinsic auditory circuits, the initial construction of functional circuits remains fundamental to understanding neural and behavioral plasticity that may lead to rational intervention and treatment outcomes.