Calcium ions play an integral role in neuron function: They act as intracellular signals that can elicit responses such as altered gene expression and neurotransmitter release from synaptic vesicles. Within the cell, calcium concentration is highly dynamic due to the presence of pumps that selectively transport these ions in response to a variety of signals. Calcium imaging takes advantage of intracellular calcium flux to directly visualize calcium signaling in living neurons.

This video begins with an overview of the key reagents used for this technique, known as calcium indicator dyes. The discussion includes an introduction to the commonly used dye Fura-2 and some basic principles behind how both ratiometric and non-ratiometric calcium indicators work. Next, a typical calcium imaging experiment is presented, from preparing the cells and dye to capturing and analyzing the fluorescent images. Finally, several experimental applications of calcium imaging are provided, such as the study of neuronal network activity and sensory processing.