PB-FI connectivity and arousal

PB-FI 连接和唤醒

• 批准号: 9883054
• 负责人: Joel Charles Geerling
• 金额: $ 19.25万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-15 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9883054
• 关键词: Affect; Anesthesia procedures; Area; Arousal; Axon; Behavior; Behavioral; Brain; Brain Stem; Brain region; Calcium; Clinical; Coma; Complement; Conscious; Consciousness Disorders; Data; Diagnosis; Diphtheria Toxin; Electroencephalography; Exhibits; FOS gene; FOXP2 gene; Felis catus; Fiber; Fluorescence; Functional Magnetic Resonance Imaging; Gene Expression; Genetic; Genetic Identity; Genetic Techniques; Human; Hypersomnolence; Impairment; Implant; Injections; Injury; Insula of Reil; Ischemic Stroke; Knowledge; Label; Lesion; Light; Location; Magnetic Resonance Imaging; Measures; Mediating; Midbrain structure; Mus; Nervous System Trauma; Neurologic; Neurology; Neurons; Neurosciences; Pathologic; Patient Care; Patients; Pattern; Pharmacology; Phenotype; Photometry; Physicians; Pontine structure; Prosencephalon; Proteins; Rattus; Recovery; Reporter; Research Personnel; Rest; Rodent; Role; Signal Transduction; Site; Sleep; System; Techniques; Testing; Tracer; Wakefulness; alpha Toxin; awake; base; clinical care; designer receptors exclusively activated by designer drugs; effective therapy; experimental study; human data; human subject; improved; in vivo; injured; mouse genetics; neuroimaging; novel; optical fiber; optogenetics; parabrachial nucleus; relating to nervous system; retrograde transport; stem; tool; vector

PROJECT SUMMARY/ABSTRACT The upper brainstem is necessary for conscious wakefulness, and lesions dividing this area from the forebrain result in deep coma. However, the neurons originating this ascending arousal system and their forebrain targets necessary for maintaining conscious wakefulness have never been identified. Currently, our ability to diagnose, prognosticate, and ultimately treat patients with disorders of consciousness is constrained by a lack of information regarding the precise location, genetic identity, and connections of these arousal-promoting neurons. We recently analyzed human brainstem lesions and identified an focal area in the upper brainstem that is injured specifically and commonly in patients presenting in coma. This coma-specific area is in the region of the parabrachial nucleus (PB), a site in which experimental lesions in rats produce deep coma. We also found that this coma-specific region exhibits strong and specific “connectivity” with the frontoinsular cortex (FI) in resting-state functional connectivity MRI (rs-fcMRI) analysis in normal human subjects. In rodents, a subpopulation of PB neurons projects directly to a homologous cortical area (agranular insular cortex), so we hypothesized that PB neurons with direct projections to the frontoinsular cortex (PB-FI) are a core component of the ascending arousal system. To test this hypothesis, we will use connectivity-based mouse genetic tools, accessing PB-FI neurons by injecting AAV6 “retro-Cre” into the insular cortex and then Cre-dependent vectors in PB. This approach allows us to selectively characterize and manipulate PB-FI neurons without altering the myriad other homeostatic functions mediated by other PB neurons. We will use this approach first to identify the full range of efferent projections of PB-FI neurons, searching for any axon collaterals to subcortical regions that may sustain arousal in parallel with FI. We will then use fiber photometry to measure the activity of PB-FI neurons from calcium transients in awake, behaving mice, and correlate their activity with concurrent behavioral state using continuous video-EEG. Finally, we will activate and ablate PB-FI neurons, testing our hypotheses that they produce wakefulness, and that their absence will result in coma or hypersomnolence. Information about their axon collaterals and activity patterns will enable optogenetic stimulation and inhibition of the fiber terminals of PB-FI neurons in target- and state-specific tests of the role of each projection of PB-FI neurons in maintaining a waking state. Ultimately, these experiments will shed much-needed light on a key, unanswered question in clinical neurology: which brainstem neurons and connections mediate basic, conscious wakefulness?

项目概要/摘要 上脑干对于有意识的清醒是必要的，而病变将该区域与前脑分开 然而，产生这种上行唤醒系统及其前脑的神经元会导致深度昏迷。 目前，我们尚未确定维持清醒状态所需的目标。 诊断、预测和最终治疗意识障碍患者的能力因缺乏 有关这些促进兴奋的精确位置、遗传身份和联系的信息 我们最近分析了人类脑干病变并确定了上脑干的一个焦点区域。 昏迷患者中特别常见的损伤区域位于昏迷区域。 臂旁核（PB）区域，大鼠实验损伤产生深度昏迷的部位。 还发现这个昏迷特定区域与额岛皮层表现出强烈且特定的“连接性” (FI) 正常人类受试者的静息态连接功能 MRI (rs-fcMRI) 分析。 PB 神经元亚群直接投射到同源皮质区域（无颗粒岛叶皮质），所以我们 促进直接投射到额岛皮层的 PB 神经元 (PB-FI) 是核心组成部分 为了检验这个假设，我们将使用基于连接的小鼠遗传工具， 通过将 AAV6“retro-Cre”注入岛叶皮层，然后注入 Cre 依赖性载体来访问 PB-FI 神经元 这种方法使我们能够在不改变 PB-FI 神经元的情况下选择性地表征和操纵 PB-FI 神经元。 我们将首先使用这种方法来识别由其他 PB 神经元介导的无数其他稳态功能。 PB-FI 神经元的全方位传出投射，搜索皮层下区域的任何轴突侧支 可能会与 FI 并行维持唤醒，然后我们将使用纤维光度法来测量 PB-FI 的活性。 来自清醒、行为小鼠的钙瞬变的神经元，并将它们的活动与并发的相关联 最后，我们将激活并消融 PB-FI 神经元，测试我们的行为状态。 假设它们会导致清醒，而它们的缺失会导致昏迷或嗜睡。 有关轴突侧支和活动模式的信息将实现光遗传学刺激和抑制 PB-FI 神经元的纤维末端在针对 PB-FI 每个投影的作用的目标和状态特定测试中的变化 最终，这些实验将揭示一个关键的关键， 临床神经学中尚未解答的问题：哪些脑干神经元和连接介导基本的、 有意识的清醒吗？