A Depth-resolved Voltage Sensitive Dye Imaging System

描述(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)神经血管耦合的研究。神经元激活与相应的血流动力学反应之间的关系对于理解功能激活的机制具有重要意义，特别是与功能磁共振成像(FMRI)的解释相关。一旦被引入大脑皮层，VSD的荧光与膜电位成比例变化，从而表明神经元活动的变化。我们已经开发了一种通过薄颅骨对大鼠皮质氧合和脱氧血红蛋白变化进行三维光学成像的系统，称为层流光学层析成像(Lot)。我们建议改进LOT的硬件和算法，以允许同时进行快速、微小的VSD荧光变化的3D成像，以及较慢的血流动力学吸收变化。LOT系统类似于共焦显微镜，但它不是改变焦深，而是探测多个散射光，这些散射光可以用于以100-200微米的分辨率重建深度为&gt；2 mm的结构的图像。到目前为止，VSD成像使用的是大脑皮质的2D相机图像，这些图像非常表面加权，无法提供深度分辨率。我们同时成像VSD和血流动力学3D图像的动机有两个：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，这两个测量必须在3D空间中共存：2D荧光图像和吸收图像的深度敏感度非常不同，因此它们的2D像素在大脑皮层中不代表相同的3D位置。2)电生理学已经证明神经元的活动是层特异性的。一种非侵入性的方法来研究神经元在皮质层之间移动和扩散时的3D激活动力学，将为在体内研究皮质功能活动提供一种全新的方法。我们建议开发荧光批次(PLOT)，然后使用接受体感刺激的大鼠进行初步系统测试。改善对神经元活动和功能磁共振信号之间的相关性的理解对人脑成像至关重要。病理异常对神经血管偶联的影响可为治疗和预防提供新的思路。新系统还可以在眼部、皮肤、内窥镜和肿瘤成像方面找到应用。

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.