Multimodal probes for multiscale calcium imaging

BRAIN Initiative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，使个别神经元和微电路的处理作用可以相关 更广泛的区域或全脑动态。在这里，我们建议创建新的神经元钙的化学探针， cium信号，这将使跨模态比较的读数获得在多个尺度上，使用两个inva， 无创和非侵入性成像方法。使用这些多功能探头，调查人员将能够记录 在不同深度和时空分辨率下的宽场神经活动动力学， 允许精确解释的源，而不存在与并行应用程序相关的潜在工件 不同的探测模式。这对于验证和使用探针在非侵入性中将是特别有价值的。 成像方式，探头技术仍然相对初级和未经测试， 场信号到微米分辨率的光学结果可以是特别有用的。我们将创造的新探测器 来自一种称为texaphryin（Tex）的细胞可渗透芳香螯合剂。Tex变体与 不同的金属离子用作有效的荧光团、光声报告物和T1加权造影剂 用于磁共振成像（MRI）。我们最近发现，结合顺磁性特克斯复合物 与钙响应性部分如1，2-双（邻氨基苯氧基）乙烷-N，N，N′，N′-四乙酸（BAPTA） 导致强烈的钙依赖性对比度变化，从而为传感器的合成提供了有希望的基础 适用于通过MRI、光学和光声读出进行同时或并行测量。在这个项目中， 我们将综合和优化多模态传感器，评估它们的光学和磁成像能力， 并开始直接利用这些新探针提供的独特优势的体内验证研究。这些 实验将建立一个第一个具有潜在的强大能力的分子平台， 在各种物种和行为中跨空间和时间尺度的神经活动动态分析 contexts.

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.