Wavefront sensor for deep imaging of the brain

 描述（由申请人提供）：光学成像在我们努力了解大脑功能方面具有巨大的前景。光学脑成像的主要挑战是深度和速度。由于强组织散射，光学显微镜在小鼠脑中的穿透深度和成像速度非常有限。深度和速度的限制使得小鼠脑活动的大规模体积成像，例如，整个小鼠皮质柱的功能成像，超出了当前成像技术的范围。自适应光学（AO）已被证明是有价值的在体内脑成像，并将有更大的影响，深部脑3光子显微镜;然而，现有的AO技术需要迭代优化使用荧光信号成像时，在散射小鼠大脑深处，这是不兼容的大规模，体积成像在大范围的深度和视野。该计划将涉及一种新的2光子Shack-Hartmann波前传感器（2P-SHWS）的发展，用于直接测量散射小鼠大脑深处的光学波前，然后演示所提出的2P-SHWS的性能，用于小鼠大脑结构和功能的体内多光子成像。该创新是基于这样的认识，即用于深层组织成像和深层组织直接波前感测的物理原理基本上是相同的，因为它们都依赖于由弹道光子携带的信息，并且它们都需要抑制来自散射激发光子的贡献。因此，平行于多光子深部组织成像背后的原理，深部组织波前感测也应该通过使用长波长和非线性激发而极大地受益。该计划的成功完成将提供前所未有的直接波前测量能力，在整个小鼠新皮层深度（800至900 µ m深），并在成像期间以1至10 Hz的更新速率（深度相关）。凭借其深层组织波前传感能力、高更新率、相对简单的实现以及零附加光漂白和光毒性，2P-SHWS被理想地定位为改变我们对小鼠脑活动的大规模体积记录的能力。

 DESCRIPTION (provided by applicant): Optical imaging holds tremendous promise in our endeavor to understand brain functions. The major challenges for optical brain imaging are depth and speed. Due to strong tissue scattering, the penetration depth and imaging speed of optical microscopy in the mouse brain are very limited. The constraints in depth and speed make large scale, volumetric imaging of mouse brain activity, e.g., functional imaging of an entire mouse cortical column, out of reach of current imaging techniques. Adaptive optics (AO) have proven to be valuable for in vivo brain imaging, and will have even larger impact for deep brain 3-photon microscopy; however, existing AO techniques require iterative optimization using fluorescence signal when imaging deep within scattering mouse brains, which is incompatible with large scale, volumetric imaging over a large range of depth and field of view. This program will involve the development of a novel 2-photon Shack-Hartmann wavefront sensor (2P-SHWS) for direct measurement of optical wavefront deep within scattering mouse brain, followed by demonstration of the performance of the proposed 2P-SHWS for in vivo multiphoton imaging of mouse brain structure and function. This innovation is based on the realization that the physical principles for deep tissue imaging and deep tissue direct wavefront sensing are essentially the same because they both rely on the information carried by the ballistic photons, and they both require the suppression of the contributions from the scattered excitation photons. Therefore, parallel to the rationales behind multiphoton deep tissue imaging, deep tissue wavefront sensing should also benefit tremendously by the use of long wavelength and nonlinear excitation. The successful completion of this program will provide the unprecedented capability of direct wavefront measurement throughout the depth of the mouse neocortex (800 to 900 µm deep) and at an update rate of 1 to 10 Hz (depth dependent) during imaging. With its deep tissue wavefront sensing capability, high update rate, relatively simple implementation, and zero additional photobleaching and phototoxicity, 2P- SHWS is ideally positioned to transform our ability for large-scale, volumetric recording of mouse brain activity.