基因编码的钙传感器将神经记录手段带进了无脊椎动物的微小大脑中，但这种方法在脊椎动物中却落在了传统的电生理方法后面。现在，Douglas Kim及其同事通过选择性“诱变”获得一种新的超灵敏的探针，即GCaMP6，它在活体中的时空分辨率从果蝇到斑马鱼都有所提高。另外，在小鼠视皮层中，GCaMP6能可靠检测单一动作电位和“单脊方向调整”。GCaMP6传感器可被用来在相隔数月的多次成像过程中对大批神经元以及微小的突触腔进行成像，从而为脑研究和钙信号作用研究提供一个灵活的新工具。（生物谷Bioon.com）
生物谷推荐英文摘要：
Nature doi: 10.1038/nature12354
Ultrasensitive fluorescent proteins for imaging neuronal activity
Tsai-Wen Chen, Trevor J. Wardill, Yi Sun, Stefan R. Pulver, Sabine L. Renninger, Amy Baohan, Eric R. Schreiter, Rex A. Kerr, Michael B. Orger, Vivek Jayaraman, Loren L. Looger, Karel Svoboda & Douglas S. Kim
Fluorescent calcium sensors are widely used to image neural activity. Using structure-based mutagenesis and neuron-based screening, we developed a family of ultrasensitive protein calcium sensors (GCaMP6) that outperformed other sensors in cultured neurons and in zebrafish, flies and mice in vivo. In layer 2/3 pyramidal neurons of the mouse visual cortex, GCaMP6 reliably detected single action potentials in neuronal somata and orientation-tuned synaptic calcium transients in individual dendritic spines. The orientation tuning of structurally persistent spines was largely stable over timescales of weeks. Orientation tuning averaged across spine populations predicted the tuning of their parent cell. Although the somata of GABAergic neurons showed little orientation tuning, their dendrites included highly tuned dendritic segments (5–40-μm long). GCaMP6 sensors thus provide new windows into the organization and dynamics of neural circuits over multiple spatial and temporal scales.
