Circuit Based Analysis of Fear and Stress

该项目研究了介导恐惧条件反射(FC)的回路中的结构和分子突触可塑性，以及受应激影响的相关回路，以及恐惧/应激相互作用的突触基础。这些实验将与项目1、4和QMC合作完成。Fc的突触基础。从内侧膝状核(MGN)和听觉皮质(AC)向杏仁外侧核(LA)的汇聚投射将通过顺行运输被标记，并在恐惧条件和对照(未配对刺激)动物中进行超微结构分析。定量免疫金将被用来建立介导FC的突触的分子图谱。我们假设Fc会改变突触的分子轮廓。还将在洛杉矶进行神经元重建，以确定FC对树突状树枝、脊柱数量和形态的影响。我们推测，作为FC的中介，分子突触改变将超过结构改变。应激引起的突触改变。我们假设慢性和急性行为应激将导致杏仁核和内侧前额叶皮质(MPFC)的突触改变，应激诱导的改变将出现在mPFC/BA回路和介导FC的听觉回路中。对于这两组回路，将评估慢性或急性应激对关键突触和树突形态的分子图谱的影响。将对LA和BA的脊柱数目进行体视学评估，以确定应激诱导的脊柱增加的核靶点。将对相互连接mPFC和BA的神经元以及LA内的神经元进行树突分枝、棘突密度和棘突形态的分析。这些研究将确定可能影响Fc的压力直接影响的电路。应激与Fc之间的交互作用。患有FC并暴露在应激中的动物将被用上面概述的相同的超微结构和形态方法进行分析，以直接评估相互作用的突触效应。此外，我们将确定杏仁核数据的失活是否会阻止mPFC中应激诱导的可塑性，就像这种失活确实会阻止FC一样。

This project investigates structural and molecular synaptic plasticity in the circuits mediating fear conditioning (FC), related circuits affected by stress, and the synaptic basis for fear/stress interactions. These experiments will be done in collaboration with Projects 1, 4, and the QMC. Synaptic basis of FC. The convergent projections to lateral amygdala (LA) from the medial geniculate nucleus (MGn) and auditory cortex (AC) will be labeled through anterograde transport and analyzed ultrastructurally in fear conditioned and control (unpaired stimuli) animals. Quantitative immunogold will be used to develop a molecular profile of the synapses mediating FC. We hypothesize that the molecular profile of the synapse will be altered by FC. Neuronal reconstructions will also be carried out in LA to determine the effects of FC on dendritic arbor, spine number, and morphology. We hypothesize that molecular synaptic alterations will predominate over structural alterations as mediators of FC. Synaptic alterations from stress. We hypothesize that chronic and acute behavioral stress will result in synaptic alterations in both amygdala and the medial prefrontal cortex (mPFC) and that stress-induced alterations will be manifested in both mPFC/BA circuits and the auditory circuits that mediate FC. The impact of chronic or acute stress on the molecular profile of key synapses and dendrites morphology will be assessed for both sets of circuits. Spine number will be assessed stereologically in both LA and BA, to determine the nuclear target of the stress-induced spine increase. An analysis of dendritic arborization, spine density, and spine morphology will be done on the neurons that reciprocally connect mPFC and BA, as well as neurons in LA. These studies will determine the circuits that are directly affected by stress that might impact FC. Interactions between stress and FC. Animals that have had FC and exposed to stress will be analyzed with the same ultrastructural and morphologic approaches outlined above to directly assess the interactive synaptic effects. In addition, we will determine whether inactivation of the amygdata blocks the stress-induced plasticity in mPFC, as such inactivation does block FC.