NEURONAL PLASTICITY IN RETINAL CIRCUIT DEVELOPMENT

描述(由申请人提供)：发育中的神经回路经历关键的精细化时期，以建立精确的连接。在这些关键时期，神经元的活动和程序性细胞死亡(PCD)塑造了神经元的解剖和功能(即神经元的可塑性)。可塑性失调已被认为是自闭症和精神分裂症等神经发育障碍的常见病因学步骤。神经元的可塑性包括轴突和树突的重塑，突触的形成和消除，突触前和突触后特化的分子结构的变化，以及对内在兴奋性的调整。虽然对个体可塑性机制的调节和作用已知很多，但不同的可塑性机制如何在神经发育过程中协同工作还不是很清楚。最近的证据表明，这些机制之间的串扰控制着它们的功能，并表明可塑性机制的相互作用取决于神经元类型和体内电路环境。在这里，我们建议研究不同的可塑性机制如何跨越体内不同水平的神经组织(突触、神经元和回路)， 不同的细胞隔间(树突和轴突)，并响应不同的触发因素(神经元活动和PCD)来塑造视网膜双极细胞(BCS)的发育和功能，视觉系统的谷氨酸能二级神经元。为此，我们建立了转基因小鼠系，它们选择性地干扰BCS的突触输入或输出，或者在BCS自然产生PCD的同时，以分级的方式去除BCS。为了分析结构和功能的可塑性，我们建立了从超分辨率显微镜到共聚焦重建和双光子实时成像的光学方法，并优化了靶向膜片钳和解剖对准多电极阵列(MEA)记录的方法。因此，我们的目标是提供一个综合的观点，即不同的活动和细胞密度依赖的可塑性机制如何协作来指导特定类型神经元的发育，以及它们在体内整合到精确的电路中。

DESCRIPTION (provided by applicant): Developing neural circuits undergo critical periods of refinement to establish precise connectivity. During these critical periods, neuronal activity and programmed cell death (PCD) shape the anatomy and function of neurons (i.e. neuronal plasticity). Dysregulation of plasticity has been identified as a common step in the etiology of neurodevelopmental disorders such as autism and schizophrenia. Neuronal plasticity encompasses axon and dendrite remodeling, synapse formation and elimination, changes in the molecular architecture of pre- and postsynaptic specializations, and adjustments to intrinsic excitability. While much is known about the regulation and action of individual plasticity mechanisms, how different plasticity mechanisms cooperate during neural development is not well understood. Recent evidence indicates that crosstalk between these mechanisms governs their function , and suggests that the interplay of plasticity mechanism depends on neuron type and in vivo circuit context. Here, we propose to study how diverse plasticity mechanisms cooperate across different levels of in vivo neural organization (synapse, neuron and circuit), in different cellular compartments (dendrite and axon), and in response to different triggers (neuronal activity and PCD) to shape the development and function of retinal bipolar cells (BCs), glutamatergic second order neurons of the visual system. Towards this end, we have generated transgenic mouse lines that selectively interfere with synaptic input to or output from BCs, or in which BCs can be removed in a graded manner concurrent with their naturally occurring PCD. To analyze structural and functional plasticity, we have established optical approaches from superresolution microscopy, to confocal reconstructions and 2-photon live imaging and optimized methods for targeted patch-clamp and anatomically aligned multielectrode array (MEA) recordings. Thus, we aim to provide an integrated view how diverse activity- and cell- density-dependent plasticity mechanisms cooperate to guide the development of a specific class of neurons and their integration into precise circuits in vivo.