Neural circuit organization and function of the bed nucleus of the stria terminalis

项目摘要/摘要 终纹床核(BNST)在恐惧和应激中起着重要作用，一直以来 与包括创伤后应激障碍(PTSD)在内的焦虑症有关。BNST包含一个集合 由细胞结构、分子和神经化学特征描绘的亚核。背侧和腹侧 前BNST的亚区包含大量表达应激相关神经元的群体 已知的神经肽，促肾上腺皮质激素释放激素(CRH)可以调节BNST相关的焦虑样行为。 我们对内源性和外源性BNST电路连接的了解大多来自经典解剖学 学习。这些研究往往具有较低的空间和细胞类型分辨率。此外，几乎没有关于 BNST内的功能性突触联系。因此，电路组织的许多方面都不是很好 明白了。我们建议利用遗传细胞靶向、分子和病毒方面的最新技术进步 示踪和功能电路图确定特定BNST神经元的突触电路组织 类型，重点是CRH+神经元。我们假设CRH表达的神经元不同地控制着神经细胞 BNST的抗焦虑和促焦虑亚区的信号输入/输出转换，以及 可以绘制这些单元类型之间的不同电路连接差异，以确定它们的特定角色 在调节应激行为反应方面。为了验证我们的假设，我们将首先绘制全局和局部电路 推测为抗焦虑和引发焦虑的亚区与CRH+神经元类型的联系(目标1)。新的基因 改进的基于狂犬病的追踪将被用来将完整大脑中的单突触全球电路连接映射到 这些精选的BNST神经元。为了从功能上验证狂犬病解剖追踪研究的结果， 局部和远程连接的生理输入特征将通过激光扫描来确定 光刺激和通道视紫红质(ChR2)辅助的电路标测。在输入映射之后，我们将映射 顺行追踪CRH+神经元类型的解剖和功能输出投影 和ChR2辅助的电路标测(目标2)。这将在下丘脑区域建立CRH+投射靶点 与调节下丘脑-垂体-肾上腺(HPA)轴活动有关。此外，行为分析 CRH+神经元类型的功能将测试特定BNST亚区中这些细胞类型是如何整合的 在更大的功能网络中，以及它们如何有助于控制应激反应(目标3)。这将会实现的 通过特定的光基因激活，同时采取生理和行为措施。总而言之，这些研究 将生成BNST中引起焦虑和缓解焦虑的亚区CRH+神经元电路连接的新图谱。 这项研究将促进我们对BNST中枢神经机制的理解，从而更好地理解和 治疗病理性焦虑症。

Project Summary / Abstract The bed nucleus of the stria terminalis (BNST) plays an important role in fear and stress, and has been implicated in anxiety disorders including posttraumatic stress disorder (PTSD). The BNST contains a collection of sub-nuclei delineated by cytoarchitecture, molecular and neurochemical features. Dorsal and ventral subregions in anterior BNST contain substantial populations of neurons that express the stress-associated neuropeptide, corticotropin-releasing hormone (CRH) known to modulate BNST-related anxiety-like behaviors. Most of what we know about intrinsic and extrinsic BNST circuit connections comes from classic anatomical studies. These studies tend to have low spatial and cell type resolution. Further, there is little work on the functional synaptic connections within the BNST. Thus many aspects of the circuit organization are not well understood. We propose to use recent technological advancements in genetic cell targeting, molecular and viral tracing, and functional circuit mapping to determine the synaptic circuit organization of specific BNST neuron types with a focus on CRH+ neurons. We hypothesize that CRH-expressing neurons differentially govern neural signal input/output transformations in anxiolytic and anxiogenic promoting subregions of the BNST, and that distinct circuit connectivity differences between these cell types can be mapped to determine their specific roles in regulating stress behavior responses. To test our hypothesis, we will first map global and local circuit connections to CRH+ neuronal types in putative anxiolytic and anxiogenic subregions (Aim 1). New genetically modified rabies-based tracing will be used to map monosynaptic global circuit connections in the intact brain to these selected BNST neurons. To functionally verify the results of the anatomical rabies tracing studies, physiological input characterization of local and long-range connections will be determined by laser scanning photostimulation and channelrhodopsin (ChR2)-assisted circuit mapping. Following input mapping, we will map anatomical and functional output projections of CRH+ neuronal types using anterograde directed viral tracing and ChR2-assisted circuit mapping (Aim 2). This will establish CRH+ projection targets in hypothalamic regions related to the regulation of hypothalamus-pituitary-adrenal (HPA) axis activity. In addition, behavioral analysis of the function of CRH+ neuron types will test how these cell types in specific BNST subregions are integrated in larger functional networks and how they contribute to control of stress responses (Aim 3). This will be achieved by specific optogenetic activation in parallel with physiological and behavioral measures. Together, these studies will generate new maps of CRH+ neuronal circuit wiring in anxiogenic and anxiolytic subregions of the BNST. This research will advance our understanding of BNST-centered neural mechanisms to better understand and treat pathological anxiety disorders.