Current application and technology of functional multineuron calcium imaging.

Here we describe recent applications and technical advancements of functional multineuron calcium imaging (fMCI), which monitors the firing activity of more than a thousand neurons through their somatic Ca(2+) signals. fMCI is used for analysis of various neural circuits under normal and pathological conditions. In vitro fMCI is made more sophisticated by using multipoint illumination and scanning technology with spinning-disk and low-laser-intensity imaging, electron-multiplying charge-coupled device cameras, etc. In vivo fMCI is still developing. We review optical technologies for fast scanning imaging, deep tissue imaging, and recording from moving animals.