in vivo imaging of inhibitory circuit remodeling in mouse visual cortex

小鼠视觉皮层抑制电路重塑的体内成像

• 批准号: 9254550
• 负责人: Elly Nedivi
• 金额: $ 39.76万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9254550
• 关键词: Address; Adult; Brain; Color; Complement; Computer Simulation; Data; Dendritic Spines; Development; Event; Excision; Excitatory Synapse; Goals; Image; Image Enhancement; Imaging technology; Individual; Inhibitory Synapse; Interneurons; Label; Lead; Length; Methods; Microscopy; Modification; Molecular; Monitor; Mus; Nature; Neocortex; Neurodevelopmental Disorder; Neurons; Ocular Dominance; Property; Signal Transduction; Specificity; Speed; Synapses; System; Therapeutic Intervention; Time; Trees; Vertebral column; Visual; Visual Cortex; Visual Pathways; Visual Perception; area striata; critical period; experience; hippocampal pyramidal neuron; in vivo; in vivo imaging; innovation; insight; interest; neocortical; postsynaptic; public health relevance; response; sensory input; synaptogenesis; temporal measurement; time interval; two-photon

 DESCRIPTION (provided by applicant): The goal of this proposal is to elucidate the mechanisms of cortical structural plasticity by combining innovative in vivo imaging technology with classical visual manipulations. This integrative approach holds the potential to revolutionize our understanding of adaptive circuit modification, a fundamental aspect of brain function. Our previous findings show that while pyramidal neurons in layer 2/3 (L2/3) of the adult mouse visual cortex show little, if any, change in branch tip length over time, GABAergic non-pyramidal interneurons display significant dendritic branch tip remodelling driven by visual experience in an input and circuit-specific manner. The fact that structural plasticity of interneurons is continuous through adulthood raises the intriguing possibility that local remodelling of inhibitory connections may underlie adult cortical plasticity. Yet, how experience alters inhibitory circuitry is unclear, and how modifications to inhibitory and excitatory circuits are locally coordinated remains unaddressed. Recently, we developed a method for labeling inhibitory synapses in vivo and simultaneously monitored inhibitory synapse and dendritic spine remodeling across the entire dendritic arbor of cortical L2/3 pyramidal neurons in vivo during normal and altered visual experience. We found that the rearrangements of inhibitory synapses and dendritic spines are locally clustered, mainly within 10 µm of each other, the spatial range of local intracellular signaling mechanisms, and that this clustering is influenced by experience. However, previous imaging intervals were typically 4 days. Thus, the nature of the coordinated inhibitory and excitatory synaptic dynamics remained temporally unresolved in terms of whether the two events occur simultaneously or one of the two drives the change, while the other adjusts to it. It is also unclear whether synapses that behave in a coordinated manner are ones driven by specific afferent inputs, and how visual experience increases coordination between excitatory and inhibitory synaptic changes. In this proposal we seek to characterize with high temporal resolution the nature of the coordinated insertion and removal of excitatory synapses and neighboring inhibitory synapses in the neocortical circuit. To this purpose we will implement a newly developed three-color labeling system to independently and simultaneously monitor postsynaptic markers representing the full synaptic complement onto individual L2/3 pyramidal neurons in mouse visual cortex. Using spectrally resolved two-photon microscopy we will 1) monitor the temporal sequence of inhibitory and excitatory synapse remodeling in vivo across the full dendritic arbor of L2/3 pyramidal neurons at short time intervals; 2) monitor the effects f experience-dependent plasticity on coordination of inhibitory and excitatory synapse remodeling; 3) examine the specificity of afferent inputs to coordinated excitatory/inhibitory synaptic pairs. Further, 4) we will develop and implement spectrally resolved multifocal multiphoton microscopy to enhance imaging speed and allow interrogation of synaptic dynamics at even shorter time intervals.

 描述（由适用提供）：该提案的目的是通过将创新的体内成像技术与经典视觉操作相结合来阐明皮质结构可塑性的机制。这种综合方法具有革新的潜力 我们对自适应电路修饰的理解，这是大脑功能的基本方面。我们先前的发现表明，尽管成年小鼠视觉皮层第2/3（L2/3）中的锥体神经元显示出几乎没有变化的分支尖端随时间而变化，但GABA能非锥体中间神经元显示出明显的树突状分支尖端，以输入和电路特异性方式通过视觉体验进行重塑。中间神经元的结构可塑性在成年期连续的事实增加了局部抑制作用的有趣可能性 连接可能是成人皮质可塑性的基础。但是，经验如何改变抑制性电路 尚不清楚，以及局部协调的抑制和兴奋回路的修改如何保持不足。最近，我们开发了一种在体内标记抑制突触的方法，并简单地监测了在正常和改变的视觉体验期间，体内抑制性突触和树突状刺重塑了整个皮质L2/3锥体神经元的树突状阵列。我们发现，抑制性突触和树突状刺的重排是局部聚集的，主要在彼此的10 µm之内，局部细胞内信号机制的空间范围，并且该聚类受经验的影响。但是，以前的成像间隔通常为4天。这是，在两个事件发生的情况下，或两者之一驱动变化，而另一个调整了它，则协调的抑制和兴奋性突触动力学的性质仍未暂时解决。还不清楚以协调方式行为的突触是否是由特定传入输入驱动的，以及视觉体验如何增加兴奋和抑制突触之间的协调。在此提案中，我们试图以高暂时的分辨率来表征，在新皮层回路中，协调插入的性质和兴奋突触的去除和相邻的抑制性突触。为此，我们将实施一个新开发的三色标记系统，以独立并简单地监视表示鼠标Visual Cortex中单个L2/3锥体神经元上完整的突触补体的突触后标记。使用光谱分辨的两光子显微镜，我们将1）在短时间间隔L2/3锥体神经元的整个树突叶伯爵中监测体内抑制性和兴奋性突触重塑的临时序列； 2）监测效果F经验依赖性的可塑性对抑制性和兴奋性突触重塑的协调； 3）检查传入输入对协调兴奋性/抑制性突触对的特异性。此外，4）我们将开发和实施频谱分辨的多焦点多光子显微镜，以提高成像速度并允许以更短的时间间隔询问突触动力学。