Synaptic Mechanisms of Hypothalamic Control of Vigilance and Cognitive Function

项目总结/摘要 这项研究的总体目标是更好地了解下丘脑组胺能（HA）是如何在脑组织中发挥作用的。 运动神经元控制行为状态转换和认知表现，使用电生理学，遗传学， 和行为学方法。K99/R 00独立之路奖的申请人， 博士亚历山大C.杰克逊目前是加州大学旧金山分校罗杰·尼科尔博士实验室的博士后研究员。杰克医生 孙的长期研究目标是阐明细胞，突触和电路水平的机制，通过这些机制， 下丘脑神经回路调节基本的行为状态，如睡眠、觉醒、注意力和 认知，健康和疾病。杰克逊博士的长期职业目标是领导一项基础神经科学研究 在一家学术研究机构担任终身制首席研究员。许多神经- 在神经精神疾病的病理生理学中涉及的大脑中的递质通路是 与那些已知的调节睡眠、觉醒和昼夜节律的基因有着千丝万缕的联系。多条线的evi- 有证据表明，下丘脑HA系统在调节觉醒，注意力和认知方面 功能此外，选择性地增强HA神经元活性的新型药物在促进HA神经元活性方面是有希望的。 清醒和增强精神分裂症和痴呆症等疾病的认知功能。然而，在这方面， 很大程度上是由于下丘脑回路的异质性， HA介导的神经传递及其在行为中的作用严重缺乏。作为他研究计划的一部分， 博士杰克逊将利用最先进的 光遗传学策略操纵遗传靶向HA神经元的兴奋性与毫秒preci， 锡永大脑切片和清醒/行为动物中，他在细胞和神经突触方面的训练- 他将继续接受光遗传学、EEG/EMG记录和行为分析方面的额外培训 与他的共同导师Luis de Lecea博士（斯坦福大学）。使用这些新工具，他将在 通过三个具体目标的多学科方式：1）使用新的光遗传学技术， 用通道视紫红质（ChR 2）靶向HA神经元，然后应用全细胞膜片钳电生理学， 脑切片，以确定突触机制的调节目标神经元兴奋性的en- dogenous HA版本（已指导）。2)为了阐明HA神经传递在一般觉醒、睡眠中的作用， 唤醒转换和认知表现，通过体内光遗传学激活HA神经元，并定量 通过两种学习行为模型， 记忆力（Mentored）3)通过评估可能的- HA/GABA共释放的性质、靶细胞特异性及其在睡眠-觉醒行为和认知中的功能作用 （独立）。K99/R 00奖励所提供的培训期将为杰克逊博士提供一个强大的 他的独立职业工具箱研究健康和疾病下丘脑功能。

PROJECT SUMMARY / ABSTRACT The overall goal of this research proposal is to better understand how hypothalamic histaminergic (HA) proje c- tion neurons control behavioral state transitions and cognitive performance, using electrophysiological, genetic and behavioral methods in transgenic mice. The applicant for the K99/R00 Pathway to Independence Award, Dr. Alexander C. Jackson, is currently a postdoctoral fellow in Dr. Roger Nicoll's laboratory at UCSF. Dr. Jack- son's long-term research goal is to elucidate the cellular, synaptic and circuit-level mechanisms through which hypothalamic neural circuits regulate fundamental behavioral states, such as sleep, wakefulness, attention and cognition, in health and disease. Dr. Jackson's long-term career goal is to lead a basic neuroscience research laboratory as a tenure-track principal investigator in an academic research institution. Many of the neuro- transmitter pathways in the brain that are implicated in the pathophysiology of neuropsychiatric illnesses are inexorably linked to those known to regulate sleep, wakefulness and circadian rhythms. Multiple lines of evi- dence implicate the hypothalamic HA system in regulating wakefulness, attention and aspects of cognitive function. Moreover, novel drugs that selectively enhance the activity of HA neurons are promising in promoting wakefulness and boosting cognitive function in disorders such as schizophrenia and dementias. However, largely owing to the heterogeneity of hypothalamic circuits, our understanding of the fundamental mechanisms of HA-mediated neurotransmission and its role in behavior is gravely lacking. As part of his research proposal, Dr. Jackson will circumvent current limitations in probing hypothalamic circuits by employing a cutting-edge optogenetic strategy to manipulate the excitability of genetically targeted HA neurons with millisecond preci- sion, in both brain slices and awake/behaving animals. By building on his training in cellular and synaptic elec- trophysiology, he will pursue additional training in optogenetics, EEG/EMG recording and behavioral analysis with his co-mentor Dr. Luis de Lecea (Stanford). Using these new tools, he will interrogate the HA system in a multidisciplinary manner through three Specific Aims: 1) To use novel optogenetic techniques to specifically target HA neurons with channelrhodopsin (ChR2) and then apply whole-cell patch clamp electrophysiology in brain slices to determine the synaptic mechanisms underlying the regulation of target neuron excitability by en- dogenous HA release (mentored). 2) To elucidate the role of HA neurotransmission in general arousal, sleep- wake transitions and cognitive performance, by optogenetically activating HA neurons in vivo, and quantifying cortical activation, sleep-wake transitions and cognitive function through two behavioral models of learning and memory (mentored). 3) To determine the role of co-transmission in the HA system, by assessing the possibil- ity of HA/GABA co-release, its target cell-specificity and its functional role in sleep-wake behavior and cognition (independent). The training period afforded by the K99/R00 Award will provide Dr. Jackson with a powerful toolbox for his independent career investigating hypothalamic function in health and disease.