Functional Segregation Within the Whisker-Barrel Neuraxis

 描述(由申请人提供)：这个多PI R01提案的长期目标有两个方面。首先，将揭示连接脑干和前脑三叉神经(V)表示的特定平行神经通路(丘脑、侧脑)的功能。这将在啮齿动物的胡须到桶状皮质神经轴上完成，由于转基因小鼠大脑皮层中的桶状突起，这已成为发现信息处理机制的首选模型。然而，我们对皮质下成分的了解存在重大空白，这阻碍了我们对胡须桶回路的掌握。这些空白将通过应用一套多学科工具来研究胡须相关感觉和运动的神经控制来填补。我们的总体假设是，脊髓V亚核内插(SpVi，Paralemniscal)中的神经活动是晶须介导的物体检测和定向反应所必需的，而晶须介导的物体识别和辨别需要在地形图(Barrelettes)V主核(PrV，Lemniscal)中的神经活动。三个特定的目标包括：a)在PRV中缺乏管状结构但在SpVi中不存在的转基因小鼠，b)可逆性生长抑素诱导腺病毒转导的多须响应性SpVi细胞或单须PRV细胞的沉默，以及c)在上述两个目标中研究的动物的V脑干神经元的完整性和神经传递特性的解剖和电生理学评估。因此，“基因缺失”和“神经沉默”方法伴随着对这两种方法在V脑干神经元中产生“功能性损伤”的程度的平行验证。这使得可以发现桶状神经轴的组件，这些组件明确地负责胡须介导的检测、定位、识别和辨别行为。其次，这项研究还将为以上列出的对腺病毒感染的神经元的抑制腺病毒诱导的沉默可能用于治疗人类神经疾病，如癫痫、慢性疼痛、肥胖症和成瘾提供技术“原则证据”，其中过度兴奋是特定神经元群体的特征，减少或消除这些疾病可能构成一种新的治疗策略。自身给药可能是一种变革性的治疗选择，其疗效将在一个简单的模型系统中进行评估，并着眼于可能的副作用。合作企业提供3个绩效指标，这些绩效指标对于实现所有3个具体目标都是不可或缺的。齐格勒博士开发了一种“头部固定”技术，用来向单个胡须传递刺激，监测它们的运动，并自愿控制它们的运动。这些工具将用于AIMS 1和AIMS 2。哈特曼博士开发了测量和控制单个胡须移动所需的“无头”技术，以及分析此类视频材料的方法。这些工具将用于AIMS 1和AIMS 2。雅克博士的职业生涯主要致力于三叉神经系统，并带来了转基因小鼠、别抑素/腺病毒和单单位记录方面的专业知识，与哈特曼博士和齐格勒博士在这里提供的行为问题和技术有关。

 DESCRIPTION (provided by applicant): The long-term objectives of this multi-PI R01 proposal are two-fold. First, the functions of specific parallel neural pathways (lemniscal, paralemniscal) linking brainstem and forebrain trigeminal (V) representations will be revealed. This will be done in the rodent whisker-to-barrel cortex neuraxis, which has become the model of choice for discovery of information processing mechanisms, due to the prominence of barrels in the cerebral cortex of transgenic mice. Yet, there are major gaps in our knowledge of subcortical components that hamper our grasp of the whisker-barrel circuit. These gaps will be filled by applying a set of multidisciplinary tools to studies of the neural control of whisker-related sensation and movement. Our overarching hypothesis is that neural activity in the spinal V subnucleus interpolaris (SpVi, paralemniscal) is necessary for whisker-mediated object detection and orientation responses, while whisker-mediated object identification and discrimination require neural activity in a topographically patterned (barrelettes) V nucleus principalis (PrV, lemniscal). Three Specific Aims employ: a) transgenic mice that lack barrelettes in PrV, but not in SpVi, b) reversible allatostatin- induced silencing of adenovirus transduced multi-whisker responsive SpVi cells or single-whisker PrV cells, and c) anatomical and electrophysiological assessments of the integrity and neurotransmission properties of V brainstem neurons in animals studied in the above 2 Aims. Thus, "gene deletion" and "neural silencing" approaches are coupled with parallel validation of the extent to which these 2 approaches produce "functional lesions" in V brainstem neurons. This permits discovery of components of the barrel neuraxis that are unequivocally responsible for whisker-mediated detection, orientation, identification and discrimination behaviors. Second, this research will als provide technical 'proof of principle' for the potential use of above- listed allatostatin-induced silencing of adenovirus infected neurons to treat human neurological disorders, such as epilepsy, chronic pain, obesity and addiction, where hyperexcitability characterizes defined neuronal populations, reduction or elimination of which could constitute a new treatment strategy. Self-administration of allatostatin could be a transformative treatment option, the efficacy of which will be evaluated here in a simple model system, with an eye towards possible side effects. A collaborative venture is offered with 3 PIs that are indispensable to the accomplishment of all 3 Specific Aims. Dr. Zeigler developed the "head-fixed" technology required to deliver stimuli to single whiskers, to monitor their movements and to bring such movements under voluntary control. These tools will be used in Aims 1 and 2. Dr. Hartmann developed the "head-free" technology required to measure and control movements of single whiskers, as well as means to analyze video materials of such. These tools will be used in Aims 1 and 2. Dr. Jacquin's career has been largely devoted to the trigeminal system and brings expertise on transgenic mice, allatostatin/adenoviruses and single unit recording to bear upon the behavioral issues and technology offered here by Drs. Hartmann and Zeigler.