The neural mechanisms involved in behavioral responses related to emotions

任何生物体最显著的特征之一是它对显著的刺激作出适当的行为反应的能力，从而最大限度地提高生存能力，最大限度地减少威胁或不愉快的事件。在哺乳动物中，情绪被认为是一种进化策略，用来检测环境的变化，指导适当的行为反应。情绪是由边缘系统中相互连接的大脑结构的复杂相互作用产生的。中叶背核（DRN）是大脑中主要的血清素能核，接收来自边缘系统不同核的信号，并通过在中枢神经系统的不同部位释放神经调节剂血清素（5-HT）来调节情绪和行为反应。实验结果表明，5-羟色胺对于处理厌恶信号很重要，而当厌恶的事情发生时，这些信号对于协调行为很重要。然而，5-HT控制情绪和行为的机制仍然是难以捉摸的。这可以通过具体测量和控制体内血清素能途径的技术困难来解释。******在这项研究计划中，我们使用创新的光遗传学和光度学方法，这将使我们能够解剖涉及情绪处理的血清素能回路。通过在老鼠身上常用的几种行为测试，我们可以将神经活动和行为联系起来。***使用创新的光遗传学操作，我们还可以人为地激活或抑制特定的神经通路，并观察这些操作如何改变行为反应。具体来说，在这个项目中，我们感兴趣的是了解外侧缰（LHb）如何控制大脑中主要的血清素能中枢——中缝背核（DRN）的活动。下脑区被认为是大脑中主要的失望中枢；它是由厌恶刺激或缺乏预期奖励（即应该产生“失望”的条件）激活的。我的初步结果让我相信，它在向DRN发送厌恶信号方面发挥着核心作用，而DRN可能在厌恶环境或预期惩罚时指导适当的行为反应。从长远来看，我们的目标是更好地了解中枢神经系统及其在细胞、突触和神经通路中的功能，这些神经通路在处理情绪信号方面发挥着重要作用，而情绪信号对协调我们的行为至关重要。**

One of the most conspicuous characteristics of any organism is its ability to react to salient stimuli with an appropriate behavioral response that maximizes survival and minimizes threatening or unpleasant events. In mammals, emotions are considered as an evolutionary strategy to detect changes from the environment to direct proper behavioral responses. Emotions are generated by the complex interaction of interconnected brain structures part of the limbic system. The dorsal raphe nucleus (DRN), the main serotonergic nucleus of the brain, receives signals from different nuclei of the limbic system and in return regulates emotions and behavioral responses by releasing the neuromodulator serotonin (5-HT) in different parts of the central nervous system. Experimental results suggest that the 5-HT would be important to process aversive signals that are important to orchestrate behaviors when something aversive is expected. However, the mechanisms by which 5-HT controls emotions and behaviors is still elusive. This can be explained by the technical difficulties in specifically measuring and controlling serotonergic pathways in vivo.******In this research proposal, we use innovative optogenetic and photometric approaches that will allow us to dissect the serotonergic circuitry involved in the processing of emotions. By using several behavioral tests commonly used in mice, we can correlate neural activity and behaviors. ***Using innovative optogenetic manipulation, we can also artificially activate or inhibit specific neural pathways and see how these manipulations can change behavioral responses. Specifically, in this program, we are interested in understanding how the lateral habenula (LHb) controls the activity of the main serotonergic center of the brain, the dorsal raphe nucleus (DRN). The LHb has been suggested to be the main disappointment center of the brain; it is activated by aversive stimuli or in absence of expected rewards (i.e. a condition that should produce “disappointment”). My preliminary results lead me to believe that it plays is central role in sending aversive signals to the DRN that may have a central role in directing proper behavioral responses in aversive contexts or when a punishment is expected. Our objectives in the longer term is to have a better understanding of the central nervous system and its function at the cellular, synaptic and its neural pathways important in the processing of emotional signals crucial to orchestrate our behaviors. **