Imaging calcium waves and sparks in central neurons

Here we describe the use of wide-field charge-coupled device (CCD) camera-based imaging methods to detect the spatial and temporal aspects of calcium release from internal stores in dendrites of neurons in brain slice preparations. This approach is useful for revealing aspects of this signaling system, which is generally invisible to electrical recording. The changes in intracellular calcium ion concentrations, [Ca(2+)](i), sometimes occur as large-amplitude, propagating Ca(2+) waves or as much smaller, localized events (sparks). In this protocol, a cell is loaded with an indicator that responds to Ca(2+), waves or sparks are stimulated in the cell, and the spatial and temporal characteristics of calcium release from internal stores in the cell are detected using wide-field CCD camera-based imaging. Such camera systems have some advantages for detecting and analyzing these [Ca(2+)](i) changes because the waves are spatially extended and the sparks do not always occur at the same locations.