Cell Type Specific Genomic and Functional Dissection of Fear Off Amygdala Pathways

与恐惧相关的疾病，如创伤后应激障碍(PTSD)，通常以 不能抑制和消除恐惧记忆，导致与恐惧相关的行为的病理性表达。 为了通过有针对性的合理设计的治疗方法取得进展，更好地理解 调节恐惧、抑制和消退的神经回路是必要的。这项提议利用了尖端的、细胞- 键入针对杏仁核的特定方法，以通过横跨多个 在美国国立卫生研究院确定恐惧相关障碍的病理生理学的战略计划中的RDoC。 我们必须了解杏仁核中支持恐惧抑制的特定细胞类型的作用 和害怕灭绝的学习。已知杏仁基底外侧核(BLA)通过 部分通过调制向杏仁中央内侧核(CEM)和外侧核(CEL)投射 通过杏仁核(ITC)接受来自内侧前额叶皮质的输入 (MPFC)，并作为细胞的抑制门。我们将针对Thy1、FoxP2和PKC亚群 在BLA、ITC、CEL中，分别被认为与恐惧抑制和消退有关 在杏仁核内--在这里被称为‘恐惧’人群。 通过各种细胞类型的特定方法，我们将确定潜在的抑制事件 杏仁核中三种“恐惧”细胞类型的恐惧。实验将在功能和分子上识别 参与这些过程的BLA、ITC和CEL内的神经元群体。我们的中央 假设BLA-ITC-CEL回路中的恐惧通路作为mPFC调节的通路。 抑制门促进在消退训练和保持过程中抑制恐惧，部分通过 MiRNA对可塑性的调控。瞄准恐惧回避途径的多个方面将扩大我们的 对恐惧抑制的理解。 这些假设将通过以下具体目标进行检验：目标1)mPFC监管 杏仁核恐惧细胞：为了确定mPFC投射到BLA的不同传入调节， ITC和CEA通过直接操纵传入神经元来“恐惧”神经元。目的2)杏仁核内 恐惧细胞的调节：确定BLA、ITC和CEA恐惧神经元在脑内的确切作用 调节杏仁核的恐惧输出回路；以及目的3)调节恐惧细胞的miRNA：确定 MiRNAs对BLA、ITC和CEA畏惧神经元的行为、神经功能和可塑性的作用 通过直接操纵miRNA功能。我们使用组合方法对函数和 杏仁核神经元的特定靶群的分子特征，这将阐明重要的 杏仁核内控制恐惧消退的微电路。新目标的识别将取得进展 我们对恐惧行为背后的回路的理解，将为治疗学提供独特的途径。

Fear-related disorders such as Post-Traumatic Stress Disorder (PTSD) are often characterized by an inability to inhibit and extinguish fear memories leading to pathological expression of fear-related behaviors. For progress to occur with targeted rationally-designed therapeutic approaches, a greater understanding of the neural circuitry mediating fear inhibition and extinction is needed. This proposal utilizes cutting-edge, cell- type specific approaches targeting the amygdala to align with NIMH research priorities by cutting across many of the RDoC in the NIH strategic plan for identifying the pathophysiology of fear-related disorders. It is critical that we understand the role of specific cell types within the amygdala supporting fear inhibition and fear extinction learning. It is known that the Basolateral Amygdala (BLA) modulates fear expression via projections to the medial (CeM) and lateral division (CeL) of the central amygdala, in part through modulation via the Intercalated Cell Nuclei of the Amygdala (ITC), which receive inputs from medial prefrontal cortex (mPFC) and act as an inhibitory gate to the CeL. We will target the Thy1, FoxP2, and PKCsubpopulations within the BLA, ITC, CeL, respectively, that are proposed to be associated with fear inhibition and extinction within the amygdala – here termed the ‘Fear-Off’ populations. Through a variety of cell-type specific approaches, we will determine the events underlying the inhibition of fear within three ‘Fear-Off’ cell types in the amygdala. Experiments will functionally and molecularly identify populations of neurons within the BLA, ITC, and CeL that participate in these processes. Our central hypothesis is that the Fear-Off pathway within the BLA-ITC-CeL circuit acts as an mPFC-regulated inhibitory gate facilitating inhibition of fear during extinction training and retention, in part through miRNA regulation of plasticity. Targeting multiple aspects of the Fear-Off pathway will expand our understanding of fear inhibition. These hypotheses will be tested through the following Specific Aims: Aim 1) mPFC Regulation of Amygdala Fear-Off Cells: To determine the differential afferent regulation from mPFC projections to BLA, ITC, and CeA ‘Fear-Off’ neurons through direct manipulation of afferent neurons. Aim 2) Intra-Amygdala Regulation of Fear-Off Cells: To determine the precise role of BLA, ITC, and CeA Fear-Off neurons in regulating fear output circuitry of the amygdala; and Aim 3) miRNA Regulation of Fear-Off Cells: To determine the role of miRNAs on behavior, neuronal function and plasticity within BLA, ITC, and CeA Fear-Off neurons through direct manipulation of miRNA function. We use a combinatorial approach to functionally and molecularly characterize specific target populations of amygdala neurons, which will elucidate important microcircuitry within the amygdala governing fear extinction. The identification of novel targets will advance our understanding of circuitry underlying fear behaviors and will provide unique avenues for therapeutics.