Photopharmacological interrogation of presynaptic neuromodulation of cortico-amygdalar circuits

项目总结 杏仁基底外侧核(BLA)是整合不同来源信息的神经中枢。 大脑反过来控制恐惧和焦虑相关的行为以及对慢性压力的反应。考虑到这个中心 神经调节G蛋白偶联受体在神经精神疾病相关情绪加工中的作用 可以控制BLA功能的GPCRs已被提议作为治疗焦虑症的靶点，并 创伤后应激障碍。然而，由于BLA电路的复杂性以及缺乏用于 在体内对GPCRs进行时空和基因上的精确操纵仍然很难理解 特定细胞类型或投射中的特定受体调节其对BLA回路功能和行为的影响。 在这里，我们将重点了解代谢性谷氨酸受体2(MGluR2)是如何调节的 使用新近发展的基因靶向光药理学研究焦虑和恐惧相关行为 结合切片电生理学、行为学、纤维光度学和RNA测序。MGluR2是一种关键 突触前G蛋白偶联受体介导突触快速抑制和诱导 长期抑郁(LTD)，尽管将这些动态突触过程与行为调节联系起来 一直是具有挑战性的。我们使用Grm2-Cre小鼠进行的初步定位研究表明，mGluR2是 丰富的投射来自腹内侧额前皮质(VmPFC)和后岛叶皮质(PIC) BLA，激发了我们对这两个投影类别的比较分析。我们将定义mGluR2的能力 在每个投射中控制皮质连接到BLA锥体神经元的突触强度和 并使用我们的光药理学工具箱将突触前调制与行为变化联系起来 通过一系列避免厌恶刺激和听觉恐惧条件反射的措施(目标1，目标2)。我们 假设根据厌恶刺激的性质(空间、躯体感觉、社会)，或者输入 来自vmPFC或PIC将在行为控制中发挥主要作用。在目标3中，我们将使用双重光生和 投射靶向RNA测序方法确定突触和分子适应发生在 每条途径都对慢性不可预测的压力做出反应。这样的分析应该对未来的小说研究有所启发 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效果。同舟共济 这个项目将介绍一种新的方法来映射行为控制的突触和回路机制 通过神经调节性GPCRs，同时为突触前对BLA的神经调节性控制提供新的见解 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.