Engineering Plasticity and Connectivity in a Fear Regulation Circuit

这是一个临床前项目，旨在开发新的方法，可能转化为临床脑刺激 严重的精神疾病。我们将测试增加两个关键大脑区域连接的技术： 下缘皮质(IL)和基底外侧杏仁核(BLA)。这个回路与恐惧和威胁反应有关。 增加IL对血乳酸的影响可能会改善恐惧调节，这反过来将与治疗相关 人类的焦虑、创伤和情绪障碍。我们将通过两种方法操作IL-BLA连接： 光遗传学，这是研究动物电路的强大工具，以及电刺激大脑，它 有希望成为治疗严重精神疾病的药物。光遗传技术非常具体，但难度很大。 因为涉及到病毒操作和硬件，所以要翻译成人类。我们的假设是我们 可以实现特定的连通性变化，从“闭环”电刺激--监测IL和 当IL变得活跃时刺激BLA。这种精确的共激活应该会唤起可塑性。 闭环刺激以前已经被开发用于马达电路应用，并已经成功 提高了大脑、脊髓和肌肉之间的连接性。我们现在将尝试证明它也可以 用于IL-BLA恐惧回路。为了具体展示闭环系统方法的优势， 我们会将其与“配对脉搏”刺激进行比较。成对的脉冲方法尝试相同类型的计时- 通过快速连续地刺激两个区域，迫使它们一起活跃，从而依赖可塑性。我们的 初步数据表明，成对脉冲技术可以增加IL-BLA的连接性。 在目标1中，我们将优化光遗传和电学参数，以提高IL-BLA在 闭合环刺激。我们将主动测量连通性(通过使用电子设备探测每个区域 刺激和观察对方的反应)和被动的(两个区域的信号在 自由行为)。我们将直接比较光刺激和电刺激，使用一种新型的光电极， 允许我们在同一只动物身上测试这两种技术。我们希望证明这两种技术可以产生 相似的结果，而且两者都可以显著改善IL-BLA的连接性。我们希望进一步证明 与“开环”成对脉冲法相比，闭环法产生更多的连通性变化。在……里面 目标2，我们将使用相同的方案来寻找持续数小时至数天的长期影响。持久耐用 对于临床翻译和使用这些基础刺激方法的效果都是重要的 实验。如果成功，我们将证明我们可以控制情绪回路的连通性 电刺激，这一发现具有直接和近期的临床意义。项目PI是一个 介入精神病学家，并准备在未来的研究中将这些发现应用于人类。

This is a pre-clinical project to develop new methods that might translate to clinical brain stimulation for severe mental illness. We will test techniques for increasing the connectivity of two key brain areas: infralimbic cortex (IL) and basolateral amygdala (BLA). This circuit is related to fear and threat response. Increasing IL's influence over BLA may improve fear regulation, which in turn would be relevant for treating human anxiety, trauma, and mood disorders. We will manipulate IL-BLA connectivity with two methods: optogenetics, which is a powerful tool for studying circuits in animals, and electrical brain stimulation, which has promise as a treatment for severe mental illness. Optogenetic techniques are very specific, but difficult to translate to humans because of the viral manipulations and hardware involved. Our Hypothesis is that we can achieve specific connectivity changes from "closed loop" electrical stimulation – monitoring IL and stimulating BLA when IL becomes active. That precise co-activation should evoke plasticity. Closed-loop stimulation has previously been developed for motor-circuit applications, and has successfully increased connectivity between brain, spinal cord, and muscle. We will now attempt to show that it can also be used in this IL-BLA fear circuit. To specifically demonstrate the advantage of the closed-loop approach, we will compare it against "paired pulse" stimulation. Paired pulse methods attempt the same kind of timing- dependent plasticity by stimulating two areas in quick succession, forcing them to be active together. Our Preliminary Data indicate that paired pulse techniques can increase IL-BLA connectivity. In Aim 1, we will optimize optogenetic and electrical parameters that increase IL-BLA connectivity during closed-loop stimulation. We will measure connectivity actively (by probing each area with electrical stimulation and seeing how the other responds) and passively (correlation of signals in the two areas during free behavior). We will directly compare optical and electrical stimulation, using a novel opto-electrode that allows us to test both techniques in the same animal. We expect to show that the two techniques produce similar results, and that both can substantially improve IL-BLA connectivity. We further expect to show that the closed-loop approach produces more connectivity change than the "open loop" paired pulse method. In Aim 2, we will use the same protocols to look for long-term effects that last hours to days. Long-lasting effects would be important both for clinical translation and for use of these stimulation methods in basic experiments. If successful, we will have shown that we can control an emotional circuit's connectivity with electrical stimulation, a finding with direct and near-term clinical relevance. The project PI is an interventional psychiatrist, and is prepared to take these findings forward into human use in future studies.