A next-generation spatial light modulator for mapping of neural networks

Boulder非线性系统(BNS)和爱德华·博伊登教授的合成神经生物学小组 麻省理工学院(MIT)媒体实验室提议开发一种新的液晶空间光 调制器(SLM)能够产生高分辨率全息图，以克服目前 将细胞水平的光遗传技术和全脑技术分开，以改善功能 绘制/剖析复杂的大脑网络。这一努力建立在成功的第一阶段努力的基础上，在这一阶段 开发了新的建模技术来指导第二阶段的硬件开发。 全脑成像技术，如功能磁共振成像(FMRI)和扩散张量 成像(DTI)是可视化神经活动和连接的强大工具，分别跨越 然而，大脑的空间分辨率仅限于毫米级，因此无法分辨 单个神经元。与此同时，光学成像和光刺激提供了免费的工具，不允许 不仅是神经元及其动作电位的直接成像，而且还有直接刺激动作电位的能力， 它们的单细胞分辨率都在小的亚毫米体积上。这种长短比例之间的脱节 全脑成像和光学技术，也就是所谓的“成像鸿沟”，是阻碍人类发展的关键障碍之一 了解如何从神经元系综的活动中产生相干态。 在第一阶段，BNS和麻省理工学院与Zemax，Inc.合作开发了一种新的光学建模能力，能够模拟 具有像素化位相调制SLM的全息显微镜。使用这种新的建模功能，BNS 通过全息寻址1×1×0.5 mm~3的组织，确定了缩小成像间隙的障碍。 具体地说，我们确定了需要一种新的SLM来最佳地平衡可寻址和可寻址之间的权衡 视场、分辨率和切换速度以及消除横向色散的矫正光学元件 被用于深层组织显微镜的超短激光脉冲所经历。 在第二阶段，BNS将开发由12V 1280×1280像素背板设计的下一代SLM 达到或超过1ms的切换速度。该设备将通过定制的矫正光学设备交付到 麻省理工学院用于演示全息询问神经元群的商业显微镜 1×1×0.5 mm~3体积的组织。

Boulder Nonlinear Systems (BNS) and Prof. Edward Boyden’s Synthetic Neurobiology Group at the Massachusetts Institute of Technology (MIT) Media Lab propose to develop a new liquid crystal spatial light modulator (SLM) capable generating high resolution holograms to overcome the “imaging gap” that currently divides cellular-level optogenetic techniques and whole brain techniques to improve functional mapping/dissection of complex brain networks. This effort builds upon the successful Phase I effort, in which new modeling techniques were developed to guide this Phase II hardware development. Whole brain imaging techniques, such as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), are powerful tools for visualizing neural activity and connections, respectively, across regions of the brain, however their spatial resolution is limited to the millimeter scale and therefore they cannot resolve individual neurons. Meanwhile, optical imaging and photostimulation provide complimentary tools that allow not only direct imaging of neurons and their action potentials, but also the ability to directly stimulate action potentials, all with single cell resolution over small sub-millimeter volumes. This disconnect between the length-scales of whole brain imaging and optical techniques, the so-called “imaging gap”, is one of the critical barriers to understanding how coherent states arise from the activity of neuronal ensembles. In Phase I, BNS and MIT worked with Zemax, Inc. to develop a new optical modeling capability able to simulate holographic microscopy with pixelated phase-modulating SLMs. Using this new modeling capability, BNS identified the barriers to closing the imaging gap by holographically addressing a 1×1×0.5 mm3 volume of tissue. Specifically, we identified the need for a new SLM that optimally balances the trade-offs between addressable field of view, resolution, and switching speed and for corrective optics that undo the lateral chromatic dispersion experienced by the ultrashort laser pulses used for deep tissue microscopy. In Phase II, BNS will develop a next-generation SLM consisting of a 12 V 1280×1280 pixel backplane designed to achieve or exceed 1 ms switching speed. This device will be delivered via custom corrective optics into a commercial microscope at MIT for demonstration of holographic interrogation of neuronal ensembles over a 1×1×0.5 mm3 volume of tissue.