Axonal myelination of interneurons in cortex: functional significance and plasticity

皮层中间神经元轴突髓鞘形成的功能意义和可塑性 有髓神经纤维中脉冲传导的速度和效率显然是神经元组成的基础。 密度和人类神经系统的功能。越来越多的证据表明， 髓鞘形成可以对局部脑回路的功能产生深远的影响，包括神经元的同步性。 活动和神经振荡器的相互作用。髓磷脂最常被认为与 长轴突投射神经元的突起。但最近，我们发现， 相对短的轴突抑制性中间神经元是皮质灰质内有髓鞘轴突的主要来源， 与几乎只在长距离投射的轴突上形成的白色物质中的髓鞘相反， 兴奋性神经元特别是，神经元间髓鞘似乎仅限于含有神经元的中间神经元。 蛋白质小清蛋白。 突触抑制是神经元网络的核心特征。在大脑皮层， interneurons参与调节兴奋/抑制平衡，在神经元同步和皮质 节奏的产生，以及与经验和学习有关的可塑性。即使轴突髓鞘形成 定义了神经元传递的关键特性，但尚未在皮质中间神经元中进行专门研究。 此外，皮质抑制回路和髓鞘的病理与许多疾病有关。 神经和精神障碍，包括多发性硬化症、精神分裂症和自闭症。我们目前 皮质灰质中髓鞘形成的知识，特别是抑制性轴突的髓鞘形成， 如果我们要克服这种破坏性的混乱，这种能力是有限的，当然也必须得到加强。 该建议基于电生理学和阵列断层扫描的新组合， 单个神经元或突触连接神经元对的功能、结构和分子数据。的 项目将开始通过研究小白蛋白阳性篮状细胞的有髓鞘轴突，并将其与 结构组织和分子组成及其作用的电生理特性 潜在的放电和导致的突触传递到目标锥体神经元上。一旦这样的基线 已经建立，小白蛋白中间神经元的轴突髓鞘形成对神经元可塑性的贡献， 将使用桶状皮层感觉剥夺作为模型来评估神经元回路。该项目将结束 研究了多发性硬化小鼠模型神经元间髓鞘形成的病理变化。 这一提议将提供关于皮层中间神经元髓鞘组织的急需数据， 功能的后果和可塑性的这个组织，及其在多发性硬化症的潜在作用。

Axonal myelination of interneurons in cortex: functional significance and plasticity The speed and efficiency of impulse conduction in myelinated fibers is clearly fundamental to component density and functional powers of the human nervous system. There is also growing evidence that changes in myelination can have profound effects on the function of local brain circuits, including synchrony of neuronal activity and the interaction of neural oscillators. Myelin is most often thought of in association with the processes of long-axon projection neurons. But recently, we have discovered that the locally-projecting, relatively short-axon inhibitory interneurons are a major source of myelinated axons within cortical gray matter, in contrast to the myelin in white matter that forms almost exclusively on the axons of long-distance projecting excitatory neurons. In particular, interneuronal myelin appears to be confined to interneurons containing the protein parvalbumin. Synaptic inhibition is a central feature of neuronal networks. In cortex, numerous types of inhibitory interneurons participate in regulating the excitatory/inhibitory balance, in neuronal synchronization and cortical rhythms generation, and in plasticity associated with experience and learning. Even though axonal myelination defines crucial properties of neuronal transmission, it has not been specifically studied in cortical interneurons. Furthermore, pathologies of both the cortical inhibitory circuitry and of myelin are associated with many neurological and mental disorders, including multiple sclerosis, schizophrenia, and autism. Our present knowledge of myelination in the cortical gray matter, and in particular the myelination of inhibitory axons, is limited and certainly must be augmented if we are to conquer such devastating disorders. This proposal is based on a novel combination of electrophysiology and array tomography that delivers functional, structural and molecular data on individual neurons or pairs of synaptically connected neurons. The project will begin by investigating myelinated axons of parvalbumin positive basket cells and correlating their structural organization and molecular composition with the electrophysiological properties of their action potential discharge and resulting synaptic transmission onto target pyramidal neurons. Once such a baseline has been established, the contribution of axonal myelination of parvalbumin interneurons to the plasticity of neuronal circuits will be assessed using barrel cortex sensory deprivation as a model. The project will conclude with a study of the pathological changes of interneuronal myelination in a mouse model of multiple sclerosis. This proposal will provide much needed data regarding the organization of myelin of cortical interneurons, the functional consequences and the plasticity of this organization, and its potential role in multiple sclerosis.