Targeting specific cortical microcircuit components to enhance functional recover

描述（由申请人提供）：2005年至2050年间，美国中风相关费用估计为2.2万亿美元，其中很大一部分是脑外伤后恢复期的护理费用，这反过来又与残疾水平高度相关。这些数字表明改善中风后神经康复的紧迫性，特别是因为没有可用的药物，也没有任何正在开发的药物，以促进中风后的功能恢复。直到最近，只有少数研究关注脑卒中后功能恢复的基本机制和潜在的改善。我们实验室之前的研究结果，以及一些关于脑卒中恢复期患者非侵入性脑刺激的有希望的人类数据，指出兴奋性/抑制性皮层回路之间的不平衡是脑卒中后功能恢复的主要障碍。我们将使用小鼠中风模型来研究如何在损伤后改善脑刺激的结果。光血栓性脑卒中将在小鼠运动皮质诱导使用一种新的中风模型开发局灶缺血诱导清醒自由运动的动物。我们将验证这一假设，即对受影响的皮层微回路的高度特异性成分的调节将为中风后的功能恢复提供最佳结果。四种不同的转基因小鼠系将用于在梗死周围区域或对侧半球等效皮质区域的兴奋性和抑制性皮层微回路进行特定的光遗传学操作。1)在梗死周围区刺激皮质锥体细胞，测试同侧刺激兴奋回路的效果；2)抑制性gaba能细胞的活性将在梗死周围区受到抑制，以减少中风后观察到的增强抑制，我们实验室先前表明，这阻碍了功能恢复的途径；3)刺激梗死周围神经胶质细胞，以测试神经胶质活性受损和继发性GABA摄取减少是否有助于观察到的抑制增强和随后的延迟功能恢复；4)在梗死灶的对侧，gaba能细胞会受到刺激，从而抑制健康运动皮层的输出，从而降低受损侧的活动。在脑卒中诱导后进行为期5天的光学刺激，每天1小时，基于无创但非特异性的人类受试者大脑模拟方案。除了对小鼠功能运动恢复的更传统的测量外，我们将使用一种新的自动测量小鼠在空气支撑球体上的运动，它可以比以前使用的运动恢复测量更好地量化。通过引入中风诱导、刺激疗法和结果指标方面的新方法，该项目解决了与美国和全世界中风带来的巨大经济和健康负担相关的科学问题。该项目还将确定在临床实践中促进康复的具体目标系统，从而使中风患者的生活更健康，功能更早恢复。

DESCRIPTION (provided by applicant): A large portion of the estimated $2.2 trillion stroke-related costs estimated in the U.S. between 2005 and 2050 pertains to the cost of care during the recovery period after the brain trauma, which in turn is highly correlated with the level of disability. These figures point to the urgency of improving post stroke neurorehabilitation, particularly since there are no drugs available, nor are there any in the pipeline, to facilitate functional recovery after stroke. Until recently, only few studies focused on the basic mechanisms and potential improvement of post stroke functional recovery. Previous findings from our laboratory, and some promising human data about non-invasive brain stimulation in recovering stroke patients, point to an imbalance between excitatory/inhibitory cortical circuits as a major obstacle in post stroke functional recovery. We will use a mouse model of stroke to examine how the outcome of brain stimulation after the injury can be improved. Photothrombotic stroke will be induced in the motor cortices of mice using a novel stroke model developed for focal ischemia induction in awake freely moving animals. We will test the hypothesis that the modulation of a highly specific component of the affected cortical microcircuits will provide the best outcome on functional recovery after stroke. Four different transgenic mouse lines will be used for specific optogenetic manipulations of excitatory and inhibitory cortical microcircuits in the peri-infarct region, or in the equivalent cortical area on the contralateral hemisphere. 1) Cortical pyramidal cells will be stimulated in the peri-infarct zone to test the effects of ipsilesonal stimulation of excitatory circuits; 2) The activity of inhibitory GABAergic cells will be suppresse in the peri-infarct zone to reduce the enhanced inhibition observed after stroke, previously shown by our lab to obstruct the path to functional recovery; 3) Peri-infarct glial cells will be stimulated to test whether impaired glial activity and a secondarily reduced GABA uptake may contribute to the observed enhancement in inhibition and the ensuing delayed functional recovery; 4) Contralateral to the infarct, GABAergic cells will be stimulated to dampen the output of the healthy motor cortex which may act to lower the activity of the lesioned side. Optical stimulation will be carried out for 5 days after stroke induction in daily 1-hour sessions, based o protocols of non-invasive, but non-specific brain simulation in human subjects. In addition to more traditional measures of functional motor recovery in mice, we will use a novel automated measurement of the mouse's movements on an air-supported sphere, which can be subjected to better quantification than previously used measures of motor recovery. By introducing novel approaches in stroke induction, stimulation therapy, and outcome metrics, the project addresses scientific questions related to the enormous economical and health burdens of stroke in both the U.S. and worldwide. The project will also identify specific target systems for promoting rehabilitation in the clinical practice, to result in a healthier life and an earlier functional reovery of stroke victims. PUBLIC HEALTH RELEVANCE: Stroke is the major cause of chronic disability worldwide and it is estimated to cost the U.S. $2.2 trillion between 2005 to 2050. A large portion of this amount pertains to the cost of care during the recovery period, which in turn is highly correlated with th level of disability. These figures point to the urgency of improving post-stroke neurorehabilitation, particularly since there are no drugs available, nor are there any in the pipeline to facilitate functional recovery after stroke. Experimental approaches in humans geared to facilitate post-stroke recovery include non-invasive and highly non-specific brain simulation. We will use a mouse model of stroke to examine how we can improve on the outcome of brain stimulation after stroke. Optical stimulation (or dampening) of the activities of specific elements of injured cortical microcircuits will be tested to find out the most effective intervention for stroke recovery. By introducing novel approaches in stroke research, the project will addresses scientific questions related to the enormous health and economical burdens of stroke in both the US and worldwide. The project will identify specific target systems that can be translated in the future into clinical practice, to accomplish a better and speedier recovery of function in stroke victims.