Interrogating the propagation of electrical stimulation across scales in vivo

项目摘要 颅内脑电刺激（EBS）仍然是临床和研究的中心方法， 几种动物模型系统。然而，人们对被激活的神经元的集合实际上知之甚少。 典型和临床颅内EBS方案。这些刺激方案通常需要反复试验 学习期（侵入性神经外科手术期间和之后），以确定刺激参数 有效，如果有的话。为什么一些刺激模式在临床上有效仍然是个谜 而另一些则没有，以及各种刺激模式激活了哪些潜在的集合。 已知局部电微刺激激活附近的可兴奋膜，包括神经细胞膜。 胞体树突和轴突还已知的是，被募集的神经元集合可以是局部非神经元的。 而且临床效果可能更多地依赖于通道轴突而不是体细胞刺激。努力 EBS模型不能克服我们目前在局部传播的均匀性方面的知识空白， 大脑的激活程度这种模糊性要求对局部电场有更详细的了解 传播，特别是在体内哺乳动物脑中。利用最新的技术进步，我们建议 为了凭经验用高密度电生理监测和时间上精确的 荧光标记方法，以高空间分辨率量化临床相关激活模式 和细胞类型特异性。 在这里，我们提出了一个实验研究的基础上，在小鼠的生物病理学现实模型的小鼠大脑 皮层，激活的空间和时间传播通过局灶性EBS。这项研究将检验这一假设 局部电刺激是非各向同性的和细胞类型特异性的。我们建议测量EBS刺激 具有超过1000个围绕刺激部位三维布置的电极，结合 通过光标记进行遗传细胞类型鉴定（Aim 1）。为了不可知地分离出全脑的激活的 通过EBS，我们将荧光报告分子与电刺激偶联用于离体全脑组织清除， 光片成像（Aim 2）。

Project Summary Intracranial electrical brain stimulation (EBS) remains a central method in the clinic as well as for research in several animal model systems. However, little is actually known about the ensembles of neurons activated by typical and clinical intracranial EBS protocols. These stimulation protocols often require a trial-and-error learning period (during and after invasive neurosurgery) to determine what stimulation parameters are effective, if any at all are effective. It remains mysterious why some stimulation patterns work in the clinic while others do not, and what underlying ensembles are activated by various stimulation patterns. It is known that focal electrical microstimulation activates nearby excitable membranes, including neural somas, dendrites, and axons. It is also known that the recruited ensemble of neurons may be locally non- homogenous and that clinical effects may rely more on axons of passage than somatic stimulation. Efforts to model EBS cannot overcome our current gaps in knowledge about the homogeneity of local propagation and brain-wide extent of activation. This ambiguity demands a more detailed understanding of local electric field propagation, particularly in the in vivo mammalian brain. Utilizing recent technological advances, we propose to fill these gaps empirically with high density electrophysiological monitoring and temporally precise fluorescent labeling methods, to quantify clinically relevant activation patterns with high spatial resolution and cell-type specificity. Here we propose an experimental study in mice, based on a biophysically realistic model of mouse cerebral cortex, of the spatial and temporal propagation of activation via focal EBS. The study will test the hypothesis that local electrical stimulation is non-isotropic and cell-type specific. We propose to measure EBS stimulation with more than 1000 electrodes arranges in three dimensions around a site of stimulation, in combination with genetic cell type identity through optotagging (Aim 1). To agnostically isolate brain-wide ensembled activated by EBS, we couple a fluorescent reporter to electrical stimulation for ex vivo whole-brain tissue clearing and light sheet imaging (Aim 2).