In Vivo Functional Imaging of the Olfactory Bulb at Single-Cell Resolution

Functional properties of neuronal circuits can be best studied in vivo in the living mammalian brain. The use of optical methods, like two-photon calcium imaging, permits analyses of network function at single-cell resolution. This chapter provides a step-by-step description of this technique. Using mouse olfactory bulb as a model system, we compare the performance of genetically encoded calcium sensor TN-XXL and small-molecule calcium indicators; describe how to choose the right calcium indicator and how to load it into the cells of interest; discuss the use of cell type-specific markers and, finally, illustrate the application of this technique for high-resolution in vivo imaging of sensory-driven neuronal activity.