Synaptic Mechanisms of Hypothalamic Control of Vigilance and Cognitive Function

项目摘要/摘要 这项研究计划的总体目标是更好地了解下丘脑组胺能(HA)如何投射c- 神经元控制行为状态转换和认知表现，使用电生理，遗传 以及转基因小鼠的行为方法。K99/R00独立之路奖申请者， 亚历山大·C·杰克逊博士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。杰克博士- 孙正义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、清醒、注意力和 认知，在健康和疾病中。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 实验室在学术研究机构担任终身教职首席研究员。很多神经细胞- 与神经精神疾病的病理生理学有关的大脑中的递质通路有 与那些已知的调节睡眠、清醒和昼夜节律的物质有着不可阻挡的联系。多行EVI- Dence在调节觉醒、注意力和认知方面牵涉到下丘脑HA系统 功能。此外，选择性增强HA神经元活性的新型药物在促进 提高精神分裂症和痴呆症等障碍患者的觉醒和认知功能。然而， 很大程度上是由于下丘脑回路的异质性，我们对基本机制的理解 关于HA介导的神经传递及其在行为中的作用的研究严重缺乏。作为他研究计划的一部分， 杰克逊博士将在探测下丘脑回路方面绕过目前的限制，利用尖端技术 以毫秒级精度操纵基因靶向HA神经元兴奋性的光遗传策略-- Sion，在脑片和清醒/行为的动物中。通过他在细胞和突触电方面的训练- 生理，他将在光遗传学、脑电/肌电记录和行为分析方面进行额外的培训 与他的合作导师Luis de Lecea博士(斯坦福)。使用这些新工具，他将在一个 通过三个具体目标采取多学科方式：1)使用新的光遗传技术来具体 通道视紫红质(ChR2)靶向HA神经元及其在全细胞膜片钳电生理中的应用 脑片以确定突触机制潜在的调节靶神经元兴奋性- 羟基磷灰石释放(指导)。2)阐明HA神经传递在一般觉醒、睡眠中的作用。 觉醒转换和认知表现，通过在体内通过光遗传激活HA神经元，并量化 大脑皮质激活、睡眠-觉醒转换和认知功能通过两种行为模型学习和 记忆(有指导)。3)确定共传播在HA系统中的作用，通过评估- HA/GABA共释放的稳定性、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/R00大奖提供的训练期将为杰克逊博士提供强大的 他的独立职业生涯工具箱，研究健康和疾病中的下丘脑功能。

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.