Calcium signaling in dendrites and spines: practical and functional considerations

Changes in intracellular calcium (Ca) concentration following synaptic and suprathreshold activity are mediated by a wide range of sources and contribute to the regulation of myriad neuronal functions. The development of Ca imaging techniques has dramatically increased our understanding of the complex interactions between different Ca sources and their ability to produce spatial and temporal specificity of signaling, even within small cellular compartments such as dendrites and dendritic spines. However, as the use of Ca imaging has become more prevalent, the need to exercise care in the experimental methodology and interpretation of data has also grown. In this review, we discuss the recent progress made using imaging methods in understanding dendritic Ca signaling and also describe a quantitative framework for using fluorescent indicators to experimentally measure and interpret changes in intracellular Ca.