Multimodal probes for multiscale calcium imaging

大脑倡议的一个主要目标是促进神经活动测量工具的发展， 空间尺度之间的桥梁，以便单个神经元和微电路的处理角色可以联系起来 到更广泛的地区性或全脑动态。在这里，我们建议创造新的神经元钙离子化学探针。 CIUM信号，将允许跨模式比较在多个尺度上获得的读数，使用INVERA和INVERA 非侵入性和非侵入性的成像方法。使用这些多功能探头，调查人员将能够记录 来自定义明确的分子的不同深度的广域神经活动动力学和时空分辨率 允许精确解释的来源，而不会出现与并行应用程序相关的伪像 完全不同的探测模式。这对于无创探头的验证和使用将特别有价值 成像模式，其中的探测技术仍然相对初级和未经测试，并与广泛的 从现场信号到微米分辨率的光学结果可能特别有用。我们将创建的新探测器 是从一种细胞渗透性的芳香族螯合剂中提取出来的，这种螯合剂被称为纹状体蛋白(Tex)。Tex变体的络合物 不同的金属离子作为有效的荧光团、光声记录器和T1加权造影剂发挥作用 用于磁共振成像(MRI)。我们最近发现，结合顺磁性TeX络合物 具有钙反应部分，如1，2-二(邻氨基苯氧基)乙烷-N，N，N‘，N’-四乙酸(BAPTA) 导致强烈的钙依赖的对比度变化，从而为传感器的合成提供了有希望的基础 适用于通过MRI、光学和光声读出器同时或并行测量。在这个项目中， 我们将对多模式传感器进行综合和优化，评估其光学和磁成像能力， 并开始体内验证研究，直接利用这些新探针提供的独特优势。这些 实验将建立首个具有潜在强大多态能力的分子平台 不同物种和行为在时空尺度上的神经活动动力学分析 上下文。

A major goal of the BRAIN Initiative is to promote the development of neural activity measurement tools that bridge between spatial scales, so that the processing roles of individual neurons and microcircuits can be related to broader regional or brain-wide dynamics. Here we propose to create novel chemical probes of neuronal cal- cium signaling that will enable cross-modal comparison of readouts obtained at multiple scales, using both inva- sive and noninvasive imaging methods. Using these multifunctional probes, investigators will be able to record wide-field neural activity dynamics at varying depths and spatiotemporal resolutions from well-defined molecular sources that permit precise interpretation, without the potential for artifacts associated with parallel application of disparate probe modalities. This will be particularly valuable for validation and use of the probes in noninvasive imaging modalities, for which probe technologies are still relatively rudimentary and untested, and relating wide- field signals to micron-resolution optical results could be especially informative. The new probes we will create are derived from a cell-permeable aromatic chelator called texaphryin (Tex). Complexes of Tex variants with different metal ions function as potent fluorophores, photoacoustic reporters, and T1-weighted contrast agents for magnetic resonance imaging (MRI). We recently discovered that combining paramagnetic Tex complexes with calcium-responsive moieties such as 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) results in strong calcium-dependent contrast changes, thus providing a promising basis for synthesis of sensors suitable for simultaneous or parallel measurement by MRI, optical, and photoacoustic readouts. In this project, we will synthesize and optimize the multimodal sensors, evaluate their optical and magnetic imaging capabilities, and begin in vivo validation studies that directly exploit the unique advantages these novel probes offer. These experiments will establish a first-of-its-kind molecular platform with potentially powerful capability for multimodal analysis of neural activity dynamics across spatial and temporal scales in a variety of species and behavioral contexts.