Abstract
Calcium (Ca(2+)) imaging is a powerful tool to investigate the spatiotemporal dynamics of intracellular Ca(2+) signals in neuronal dendrites. Ca(2+) fluctuations can occur through a variety of membrane and intracellular mechanisms and play a crucial role in the induction of synaptic plasticity and regulation of dendritic excitability. Hence, the ability to record different types of Ca(2+) signals in dendritic branches is valuable for groups studying how dendrites integrate information. The advent of two-photon microscopy has made such studies significantly easier by solving the problems inherent to imaging in live tissue, such as light scattering and photodamage. Moreover, through combination of conventional electrophysiological techniques with two-photon Ca(2+) imaging, it is possible to investigate local Ca(2+) fluctuations in neuronal dendrites in parallel with recordings of synaptic activity in soma. Here, we describe how to use this method to study the dynamics of local Ca(2+) transients (CaTs) in dendrites of GABAergic inhibitory interneurons. The method can be also applied to studying dendritic Ca(2+) signaling in different neuronal types in acute brain slices.