Postnatal maturation of cortical microcircuit function in barrel cortex

啮齿类动物的桶状皮层作为一个模型系统，研究感觉加工和感觉运动整合在哺乳动物的新皮层。一个有前途的方法，以获得深入了解桶皮质的神经元微电路的功能组织是研究幼年动物的出生后成熟，并将其与行为的发展。在未来的几年中，我们的目标是阐明在出生后的发展采用最先进的体内成像技术在小鼠桶皮质的浅层神经元网络活动的功能成熟。我们将关注出生后第2周和第3周，这是一个关键的时间段，在此期间，小鼠开始探索它们的环境并开始积极的搅拌行为。我们的目标是剖析在此期间的功能变化的单细胞和网络机制的贡献，特别是不同的interneuron亚型的作用和稳定的兴奋抑制比及其对感觉输入的依赖。我们还旨在区分输出神经元的亚群，无论是初级运动皮层（M1）或次级体感区（S2），以揭示皮质激活模式的发展。由于在幼年小鼠中进行纵向、慢性钙成像被证明是困难的，因此我们将重点放在急性钙成像实验上，结合转基因小鼠、电生理学和事后免疫染色。虽然在麻醉期间将研究单细胞和局部神经元群体的自发和胡须诱发活动的基本特性，但我们也将尝试在自愿主动搅拌期间测量清醒的幼年小鼠的网络动力学，从而将电路动力学的成熟与这种新兴的突出行为直接联系起来。

The rodent barrel cortex serves as a model system for investigating sensory processing and sensorimotor integration in the mammalian neocortex. A promising approach to gain insights into the functional organisation of the neuronal microcircuit in barrel cortex is to study postnatal maturation in juvenile animals and relate it to the development of behaviour. In the coming years we aim to elucidate the functional maturation of neuronal network activity in the superficial layers of mouse barrel cortex during postnatal development employing state of the art in vivo imaging techniques. We will focus on postnatal weeks 2 and 3, a critical time period during which mice begin to explore their environment and start active whisking behaviour. We aim to dissect the contributions of single-cell and network mechanisms underlying functional changes during this period, in particular the role of different interneuron subtypes and the stabilization of the excitation to inhibition ratio and its dependence on sensory input. We also aim to discriminate subpopulations of output neurons that project to either primary motor cortex (M1) or secondary somatosensory area (S2), in order to reveal how corticocortical activation patterns develop. Because longitudinal, chronic calcium imaging in juvenile mice turned out to be difficult, we will focus on acute calcium imaging experiments, combined with transgenic mice, electrophysiology and post-hoc immunostaining. While basic properties of spontaneous and whisker-evoked activity of single cells and local neuronal populations will be studied during anaesthesia, we will also attempt to measure network dynamics in awake juvenile mice during voluntary active whisking, thus directly linking the maturation of circuit dynamics to this emerging prominent behaviour.