Photopharmacological interrogation of presynaptic neuromodulation of cortico-amygdalar circuits

项目摘要 基底外侧杏仁核（BLA）作为神经中枢，用于整合来自整个大脑的各种输入。 反过来，大脑控制恐惧和焦虑相关的行为以及对慢性压力的反应。鉴于这一中心 在神经精神疾病相关情绪处理中的作用，神经调节G蛋白偶联受体 已经提出可以控制BLA功能的GPCR（GPCR）作为治疗焦虑症的靶标， 创伤后应激障碍然而，由于BLA电路的复杂性和缺乏用于 尽管GPCR在体内的时空和遗传精确操纵，但仍然难以理解如何在体内精确操纵GPCR。 特定细胞类型或投射中的特定受体介导它们对BLA回路功能和行为的影响。 在这里，我们将重点了解代谢型谷氨酸受体2（mGluR 2）如何调节 焦虑和恐惧相关的行为，使用最近开发的基因靶向药物， 结合切片电生理学、行为学、纤维光度学和RNA测序。mGluR 2是一个关键的 突触前G蛋白偶联受体（GPCR）介导快速突触抑制和诱导 长期抑郁症（LTD），虽然连接这些动态突触过程的行为调制 一直很有挑战性我们使用Grm 2-Cre小鼠进行的初步定位研究表明，mGluR 2是 丰富了从腹内侧前额叶皮层（vmPFC）和后岛叶皮层（pIC）到 BLA，激发我们对这两个投射类的比较分析。我们将定义mGluR 2 在每个投射中控制皮质连接到BLA锥体神经元的突触强度， 并使用我们的神经药理学工具集将突触前调制与行为变化联系起来 通过一系列的措施，避免厌恶刺激和听觉恐惧条件反射（目的1，目的2）。我们 我假设，根据厌恶刺激的性质（空间，体感，社会）或输入 来自vmPFC或pIC的信号将在行为控制中起主要作用。在目标3中，我们将使用双重光遗传学和 投射靶向RNA测序方法来定义突触和分子适应，发生在 每一条通路都是对慢性不可预测的压力的反应。这样的分析应该为未来的小说研究提供参考 投射定义的药物靶点，可以对恐惧和焦虑的不同方面产生预期的效果。一起 本计画将介绍一种新的方法来描绘行为控制的突触与回路机制 通过神经调节GPCRs，同时提供了新的见解，通过突触前的BLA的神经调节控制 mGluR2。

PROJECT SUMMARY The basolateral amygdala (BLA) serves as a neural hub for the integration of various inputs from across the brain to, in turn, control fear and anxiety-related behaviors and the response to chronic stress. Given this central role in neuropsychiatric disease-relevant emotional processing, neuromodulatory G protein-coupled receptors (GPCRs) that can control BLA function have been proposed as targets for the treatment of anxiety disorders and post-traumatic stress disorder. However, due to the complexity of BLA circuits and the lack of tools for spatiotemporally and genetically precise manipulation of GPCRs in vivo, it remains difficult to understand how specific receptors in defined cell types or projections mediate their effects on BLA circuit function and behavior. Here we will focus on an understanding of how metabotropic glutamate receptor 2 (mGluR2) modulates anxiety and fear-related behaviors using recently developed genetically-targeted photopharmacology in conjunction with slice electrophysiology, behavior, fiber photometry and RNA sequencing. mGluR2 is a critical presynaptic G protein-coupled receptor (GPCR) which mediates both rapid synaptic inhibition and the induction of long-term depression (LTD), although connecting these dynamic synaptic processes to behavioral modulation has been challenging. Our preliminary mapping studies using a Grm2-Cre mouse have shown that mGluR2 is enriched in projections from the ventromedial prefrontal cortex (vmPFC) and posterior insular cortex (pIC) to the BLA, motivating our comparative analysis of these two projection classes. We will define the ability of mGluR2 in each projection to control the synaptic strength of cortical connection to BLA pyramidal neurons and interneurons and use our photopharmacological toolset to link presynaptic modulation to behavioral changes across a battery of measures of avoidance to aversive stimuli and auditory fear conditioning (aim 1, aim 2). We hypothesize that depending on the nature of the aversive stimulus (spatial, somatosensory, social) either inputs from the vmPFC or pIC will play primary roles in behavioral control. In aim 3, we will use a dual optogenetic and projection-targeted RNA sequencing approach to define the synaptic and molecular adaptations that occur in each pathway in response to chronic unpredictable stress. Such analysis should inform future studies of novel projection-defined drug targets that can have desired effects on different aspects of fear and anxiety. Together this project will introduce a novel approach to mapping the synaptic and circuit mechanisms of behavioral control by neuromodulatory GPCRs while providing new insights into neuromodulatory control of the BLA by presynaptic mGluR2.