癫痫模型动物中本能恐惧反应异常的神经环路机制研究

The aim of this project is to figure out the innate fear-related neural circuits in epilepsy animal model. Previous studies reported that people with epilepsy showed more brain disorder and elevated premature mortality than general population controls. What the most remarkable finding is that deaths from external causes was the largest category of deaths that was not clearly related to underlying disease processes. What are the underlying causes? As we all know, innate fear, one of the defensive behavior, is critical for survival of individuals. So, we used the Kainic acid-induced epileptic mice testing if epilepsy animals involved with innate fear abnormal. Then, we preliminary found that the epilepsy mice show decreased innate fear and neurons activity in hippocampus, amygdala, hypothalamus was abnormal during innate fear test. Besides, our previous study showed that the hippocampus function is abnormal and it will affect its downstream brain area. Moreover, in epileptic animal hippocampus structure is damaged and its neural circuits should be reformed most likely. Thus, this project aims to finish: 1) the characters of epileptic mice innate fear responses; 2) the neural circuit mechanism of predator fear in epilepsy mice; 3) effective modulation targets to rescue the abnormal predator fear behavior. Based on our knowledge and preliminary studies we will focus on how hippocampus –hypothalamus circuits contribute to the reduced innate fear in epileptic mice. For all this, we will combine some intersectional technologies in our research, such as optogenetics, transsynaptic tracing, clarity, multi-area in vivo recording, c-fos mapping, optical recording in vivo and so on. In summary, the goal of this program is to better understand why premature mortality from external causes in epilepsy is more than general population controls, and then to facilitate the life of people with epilepsy.

目的：阐明癫痫模型动物中本能恐惧反应异常的神经环路机制。本研究将以药物诱导的癫痫小鼠为研究对象，基于之前癫痫中海马输出环路功能异常的发现，整合光遗传调控、多脑区电生理记录、神经环路示踪、在体荧光检测等技术研究：1）在捕食者恐惧行为范式中癫痫小鼠本能恐惧反应的特征；2）导致癫痫小鼠捕食者恐惧异常的神经环路机制；3）纠正癫痫小鼠异常的本能恐惧行为的有效环路靶点。本研究将明确：1）癫痫小鼠本能恐惧反应异常行为特征；2）癫痫本能恐惧反应异常的可能环路机制：下丘脑恐惧相关亚区接受来自海马的恐惧信息输入下降，神经活动下降，最终导致动物恐惧反应减弱；3）纠正该异常本能恐惧行为可能的环路靶点：下丘脑兴奋性神经元。本项目将从捕食者恐惧异常的环路机制出发，探索癫痫本能行为特征及其发生、调控的神经机制，为改善癫痫患者意外死亡率高提供新的研究视角，为临床上改善癫痫患者整体治疗效果提供新策略，具有理论、临床意义。

癫痫是一种常见的神经系统疾病，它的危害不仅在于频繁而不可预知性的癫痫发作，还在于它是一个症候群，具有很多共患病，以及过早死亡率升高的问题，该疾病导致大量患者不能正常的学习和工作，给癫痫患者家庭乃至社会造成了沉重的负担，因此，深刻理解该疾病共患病问题，为全面治疗癫痫这种症候群至关重要。本项目主要在癫痫模型动物上，研究癫痫共患本能恐惧异常的神经环路机制：1）通过捕食者恐惧行为检测癫痫模型动物是否存在本能恐惧异常；2）通过c-Fos mapping检测本能恐惧行为中相关脑区神经元激活是否存在异常；3）通过环路示踪和电生理的方法验证发生异常的脑区之间的环路连接以及其结构和功能在癫痫中是否也发生改变；4）通过监测捕食者恐惧行为下的相关环路的电生理特征，解析该环路参与捕食者恐惧异常的神经编码机制；5）通过光遗传调控的方法改变其捕食者行为，进而寻找可能的调控靶点。我们发现：1）癫痫模型动物本能恐惧异常下降，2）且在捕食者恐惧行为中海马、隔核、下丘脑等脑区的神经元激活异常，3）进一步我们发现了一条dCA3-dLS-DMH环路，4）该环路主要通过θ-α波参与捕食者恐惧行为，5）而光遗传调控激活CA3区域的谷氨酸能神经元能够获得与癫痫模型动物上类似的捕食者恐惧异常下降行为，提示我们CA3的谷氨酸能神经元活动的调控可能是调节癫痫本能恐惧异常的有效靶点。下一步我们需要验证CA3中神经元尤其是谷氨酸能神经元参与θ-α波的编码机制，以及通过调控他们纠正癫痫模型动物上异常的本能恐惧行为的调控模式是什么。6）为此，我们开发了一系列关键的柔性光遗传和电生理记录电极的技术。上述相关新的技术不仅可应用于本项目的研究，还通过培训班的载体推广到其他实验室，以期用于更多的神经环路解析和调控相关研究。此外，我们已经基于本项目的上述发现，启动了与医院的合作，希望能够对临床中癫痫疾病的全面治疗给予帮助或指导。