In vivo chronic imaging of neuronal circuit plasticity using a genetically-encoded calcium sensor

为了建立慢性体内双光子钙成像，我们产生了转基因小鼠，其在皮质的第5层和海马的CA1中稳定表达遗传编码的钙传感器GCaMP4。我们的体内双光子成像证实，这些小鼠的海马CA1区锥体细胞中的GCaMP4的荧光迅速增加，并大幅响应于药理学诱导的神经元回路活动的升高。因此，这些转基因小鼠将成为一个有价值的工具，纵向成像研究学习诱导的神经元回路可塑性的大脑。

To establish chronic in vivo two-photon calcium imaging, we generated transgenic mice that stably express a genetically-encoded calcium sensor GCaMP4 in layer 5 of cortex and CA1 of hippocampus. Our in vivo two-photon imaging confirmed that the fluorescence of GCaMP4 in hippocampal CA1 pyramidal cells of these mice increased rapidly and substantially in response to pharmacologically-induced elevation of neuronal circuit activity. These transgenic mice will thus become a valuable tool for longitudinal imaging studies of learning-induced neuronal circuit plasticity in the brain.