Single cell resolution multiscope recording and manipulation of striatal circuitry during decision making

这项提议的目的是在麦吉尔大学的行为小鼠身上同时实施多区域、单细胞分辨率的神经记录和操作。这项令人兴奋的新技术可以在多达四个大脑区域对两个神经活动的荧光指示器进行成像，并结合有针对性的光遗传操作，所有这些都是在单细胞分辨率下进行的。它将在心理学系的两位CRC教授乔纳森·布里特博士和罗斯玛丽·巴格特博士的实验室中使用，以调查遗传定义的纹状体神经元的整体活动是如何在不同行为状态的皮质-中-边缘回路中协调的。单细胞多范围成像将在两个关键方面极大地加速NSERC资助的两个申请者的研究。首先，这项技术在提供跨自由活动小鼠多个大脑区域的神经活动的同时单细胞测量方面是独一无二的，从而允许对行为相关回路中细胞类型内和跨细胞类型的网络活动进行高分辨率计算分析。其次，它允许完全集成的光遗传操作，可以针对不同的细胞亚群。这项技术完美地补充了两个实验室在种群水平记录技术(如纤维光度法)方面的专业知识。虽然强大，但人口层面的技术不能解决某些现象。例如，信号的增加可能是由活跃细胞数量的增加或稳定细胞群体的同步性增加所驱动的。最近有证据表明，多巴胺不会改变活跃神经元的放电率，而是决定在行为过程中招募多少纹状体神经元(即活跃整体的大小；Maltese等人，eLife 2021)，这突显了在投射和遗传定义的人群中解决单细胞活动的必要性。因此，为了确定纹状体回路如何对多巴胺信号的精确扰动做出反应(Britt实验室)，并最终整合关于奖赏和损失的信息(Bagot实验室)，单细胞分辨率对于跟踪整个纹状体传入和传出细胞群体的整体大小、身份、一致性和活动平衡至关重要。这项技术的实施将促进与计算神经学家在McGill内外的合作，因为独特的丰富的生理和行为数据提供了有趣的机会来测试关于神经元网络的计算理论，以及降维技术和动态模式分析的发展。该设备将支持HQP的招聘，因为它为HQP提供了尖端的培训机会，并增加了研究的整体影响。

This proposal aims to implement simultaneous multi-region, single-cell resolution neural recording and manipulation in behaving mice at McGill University. This exciting new technology enables imaging two fluorescent indicators of neural activity in up to four brain regions, in combination with targeted optogenetic manipulations, all at single-cell resolution. It will be used in the labs of Drs. Jonathan Britt and Rosemary Bagot - two CRC professors in the Department of Psychology - to investigate how ensemble activity of genetically-defined striatal neurons is coordinated within cortico-meso-limbic circuits across varying behavioural states. Single-cell multiscope imaging will dramatically accelerate the NSERC-funded research of both applicants in two key ways. First, this technology is unique in providing simultaneous single-cell measurement of neural activity across multiple brain regions in freely moving mice, thus permitting high-resolution computational analysis of network activity within and across cell types in behaviourally-relevant circuits. Second, it allows for fully integrated optogenetic manipulations that can be targeted to subsets of cells. The technology ideally complements the expertise of both labs in population-level recording techniques such as fiber photometry. While powerful, population-level techniques cannot resolve certain phenomena. For example, an increase in signal could be driven by an increase in the number of active cells or by increased synchrony of a stable population of cells. The necessity to resolve single-cell activity in projection- and genetically-defined populations was recently underscored by demonstrations that dopamine does not alter the firing rate of active neurons but rather determines how many striatal neurons get recruited during behaviour (i.e., the size of the active ensemble; Maltese et al., eLife 2021). Thus, to identify how striatal circuits respond to precise perturbations of dopamine signaling (Britt lab) and ultimately integrate information about reward and loss (Bagot lab), single-cell resolution is critical for tracking the ensemble size, identity, coherence, and balance of activity across striatal afferent and efferent cell populations. Implementation of this technology will promote collaborations with computational neuroscientists within and beyond McGill, as the uniquely rich physiological and behavioural data offer interesting opportunities to test computational theories about neuronal networks as well as development of dimensionality reduction techniques and dynamic pattern analyses. This equipment will support HQP recruitment, as it provides cutting-edge training opportunities for HQP and increases the overall impact of the research.