Novel technologies for nontoxic transsynaptic tracing

 描述（由申请人提供）：遗传工具已经显著提高了神经科学实验的能力和分辨率，允许监测和干扰大脑内的特定神经元群体，通常在复杂的认知和行为范例的背景下。然而，这些工具的有用性受到以电路特定方式递送它们的可用手段的限制，鉴于单个神经元之间和神经元类之间的特定连接的至关重要性，这是一个主要缺点。基于神经元的突触连接实现转基因表达的主要可用手段是基于病毒的跨突触追踪，其允许识别、活性成像、光遗传学控制和体内突触连接的神经元网络中基因表达的扰动。然而，所需的病毒在几天内就会产生毒性，排除了解决神经科学中许多核心问题所需的长期实验。我们将通过设计病毒跨突触追踪系统来解决这个问题，该系统的毒性大大降低或完全消除，从而使已知连接的神经元网络在认知和行为中的作用。其结果将是一套工具，将允许光学成像，生理记录，并在行为和其他实验范式持续数周，数月或数年的背景下，在任何哺乳动物模型物种已知的突触连接的神经元网络的活动和基因表达的操纵。这将极大地增强我们对正常认知以及神经和精神障碍的神经基础的理解。

 DESCRIPTION (provided by applicant): Genetic tools have dramatically increased the power and resolution of neuroscientific experiments, allowing monitoring and perturbation of specific neuronal populations within the brain, often in the context of complex cognitive and behavioral paradigms. However, the usefulness of these tools is limited by the available means of delivering them in circuit-specific ways, a major drawback in view of the critical importance of specific connectivity between individual neurons and between neuronal classes. The primary available means of achieving transgene expression based on neurons' synaptic connections is virus-based transsynaptic tracing, which allows identification, activity imaging, optogenetic control, and perturbation of gene expression in networks of synaptically connected neurons in vivo. The required viruses, however, are toxic within a few days, precluding longer-term experiments that are needed to address many central questions in neuroscience. We will solve this problem by engineering viral transsynaptic tracing systems with either greatly reduced or entirely eliminated toxicity, so that the role of neuronal networks of known connectivity in cognition and behavior. The result will be a set of tools that will allow optical imaging, physiological recording, and manipulation of the activity and gene expression of neuronal networks of known synaptic connectivity in the context of behavioral and other experimental paradigms lasting weeks, months, or years, in any mammalian model species. This will greatly enhance our understanding of the neural bases of normal cognition as well as neurological and mental disorders.