Targeting specific cortical microcircuit components to enhance functional recover

描述（由申请人提供）：2005年至2050年期间，美国估计的2.2万亿美元中风相关费用中，很大一部分与脑外伤后恢复期的护理费用有关，这反过来又与残疾程度高度相关。这些数字表明了改善卒中后神经康复的紧迫性，特别是因为没有可用的药物，也没有任何药物在管道中，以促进卒中后的功能恢复。目前，关于脑卒中后功能恢复的机制和改善作用的研究较少。我们实验室以前的发现，以及一些关于恢复中风患者的非侵入性脑刺激的有希望的人类数据，指出兴奋/抑制皮层回路之间的不平衡是中风后功能恢复的主要障碍。我们将使用中风的小鼠模型来研究如何改善损伤后的脑刺激结果。使用为在清醒自由活动动物中诱导局灶性缺血而开发的新型卒中模型，在小鼠的运动皮质中诱导光血栓性卒中。我们将测试的假设，即受影响的皮层微电路的高度特定的组件的调制将提供中风后的功能恢复的最佳结果。四种不同的转基因小鼠系将用于梗塞周围区域或对侧半球上的等同皮质区域中的兴奋性和抑制性皮质微电路的特异性光遗传学操作。1)在梗塞周围区刺激皮质锥体细胞以测试兴奋性回路的同相刺激的效果; 2）在梗塞周围区抑制性GABA能细胞的活性将被抑制以减少中风后观察到的增强的抑制，该增强的抑制先前被我们的实验室显示为阻碍功能恢复的路径; 3）刺激梗塞周围神经胶质细胞以测试受损的神经胶质活性和继发性减少的GABA摄取是否可能有助于观察到的抑制增强和随后的延迟功能恢复; 4）在梗塞的同侧，GABA能细胞将被刺激以抑制健康运动皮层的输出，这可以起到降低损伤侧的活动的作用。在中风诱导后，将在每天1小时的疗程中进行光学刺激，持续5天，基于人类受试者的非侵入性但非特异性脑模拟的方案。除了更传统的措施，在小鼠的功能运动恢复，我们将使用一种新的自动测量小鼠的运动在空气支持的球体，它可以进行更好的量化比以前使用的运动恢复的措施。通过引入中风诱导，刺激治疗和结果指标的新方法，该项目解决了与美国和全球中风的巨大经济和健康负担相关的科学问题。该计划亦会确定具体的目标系统，以促进临床实践中的康复，从而使中风患者的生活更健康，功能更早恢复。 公共卫生相关性：中风是全球慢性残疾的主要原因，据估计，2005年至2050年期间，美国将花费2.2万亿美元。其中很大一部分 与康复期间的护理费用有关，而康复期间的护理费用又与残疾程度高度相关。这些数字表明了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，也没有任何药物可以促进中风后的功能恢复。用于促进中风后恢复的人类实验方法包括非侵入性和高度非特异性的大脑模拟。我们将使用中风的小鼠模型来检查我们如何改善中风后脑刺激的结果。光学刺激（或阻尼）受伤的皮层微电路的特定元素的活动将进行测试，以找出最有效的干预中风恢复。通过引入中风研究的新方法，该项目将解决与美国和世界范围内中风的巨大健康和经济负担相关的科学问题。该项目将确定未来可以转化为临床实践的特定目标系统，以实现中风患者更好，更快的功能恢复。

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.