Calcium imaging in the Drosophila olfactory system with a genetic indicator

Insects show sophisticated odor-mediated behaviors controlled by an olfactory system that is genetically and anatomically simpler than that of vertebrates, providing an attractive system to investigate the mechanistic link between behavior and odor perception. Advances in neuroscience have been facilitated by modern optical imaging technologies--both in instrumentation and in probe design--that permit the visualization of functional neural circuits. Imaging calcium activity in genetically defined populations of neurons provides an important tool for investigating the function of neural circuits. This article describes a two-photon imaging system for monitoring neural activity in the Drosophila antennal lobe. Odor-evoked calcium activity is followed by measuring the specific expression of the calcium-sensitive green fluorescent protein G-CaMP in Drosophila antennae-brain preparations.