A Depth-resolved Voltage Sensitive Dye Imaging System

描述（由申请人提供）：我们建议开发一种用于电压敏感染料（VSD）和皮质血流动力学的深度分辨光学成像系统，以实现体内（大鼠）三维（3D）神经血管耦合研究。神经元激活和相应的血流动力学反应之间的关系是理解功能激活的机制，特别是相关的功能磁共振成像（fMRI）的解释是至关重要的。一旦被引入皮层，VSD就与膜电位成比例地改变其荧光，从而指示神经元活动的变化。我们已经开发了一个系统，用于通过薄颅骨对大鼠皮层中的氧合和脱氧血红蛋白变化进行三维光学成像，称为层流光学断层扫描（LOT）。我们建议改进LOT的硬件和算法，以允许除了较慢的血流动力学吸收变化之外，还可以对快速、小的VSD荧光变化进行并行3D成像。LOT系统类似于共焦显微镜，但不是改变焦深，而是检测多重散射光，其可用于以100-200微米的分辨率重建深度> 2 mm的结构的图像。迄今为止，VSD成像利用了皮质的2D相机图像，其非常肤浅地加权并且不提供深度分辨率。我们在3D中同时成像VSD和血流动力学的动机是双重的：1）我们假设为了正确量化神经活动和血流动力学之间的关系，这两种测量必须在3D中空间共定位：2D荧光和吸收图像的深度灵敏度非常不同，因此它们的2D像素不代表皮层中相同的3D位置。2)电生理学已经证明神经元活动是层特异性的。一种非侵入性的方法来研究神经元激活的3D动力学，因为它在皮质层之间移动和传播，将提供一个全新的方式来研究体内皮质功能活动。我们建议开发一个新的PLOT系统，然后使用大鼠进行初步的系统测试，进行体感刺激。对神经元活动和功能磁共振成像信号之间的相关性的进一步理解对人脑成像至关重要。异常病理对神经血管耦联的影响可以为治疗和预防提供新的见解。新系统还可以应用于眼部、皮肤、内窥镜和肿瘤成像。

DESCRIPTION (provided by applicant): We propose to develop a system for depth-resolved optical imaging of both voltage sensitive dyes (VSDs) and cortical hemodynamics, to enable study of three-dimensional (3D) neurovascular coupling in-vivo (rats). The relationship between neuronal activation and the corresponding hemodynamic response is of fundamental importance for understanding the mechanisms of functional activation, and particularly relevant to interpretation of functional magnetic resonance imaging (fMRI). Once introduced into the cortex, VSDs change their fluorescence proportionally to membrane potential, thereby indicating changes in neuronal activity. We have already developed a system for 3D optical imaging of oxy and deoxy-hemoglobin changes in rat cortex through thinned skull, called Laminar Optical Tomography (LOT). We are proposing to advance LOT.s hardware and algorithms to allow concurrent 3D imaging of rapid, small VSD fluorescence changes in addition to slower hemodynamic absorption changes. The LOT system is similar to a confocal microscope, but rather than varying focal depth, it detects multiply scattered light, which can be used to reconstruct images of structures to depths of >2mm with 100-200 micron resolution. VSD imaging to date has utilized 2D camera images of the cortex, which are very superficially weighted and provide no depth-resolution. Our motivation to simultaneously image VSDs and hemodynamics in 3D is twofold: 1) We hypothesize that to properly quantify the relationship between neural activity and hemodynamics, the two measures must be spatially co-localized in 3D: The depth-sensitivities of 2D fluorescence and absorption images are very different, and so their 2D pixels do not represent the same 3D locations in the cortex. 2) Electrophysiology has demonstrated that neuronal activity is layer-specific. A non-invasive way to study the 3D dynamics of neuronal activation as it moves and spreads between cortical layers would provide a completely new way to study cortical functional activity in-vivo. We propose to develop Fluorescent-LOT (PLOT) and then perform preliminary system testing using rats undergoing somatosensory stimulus. Improved understanding of the correlation between neuronal activity and fMRI signals is of prime importance to human brain imaging. The effects of abnormal pathologies on neurovascular coupling could provide new insights for treatment and prevention. The new system could also find applications in ocular, dermal, endoscopic and tumor imaging.