Real-time optical imaging of neuronal activity

The availability of suitable voltage-sensitive dyes and arrays of photodetectors has facilitated the optical monitoring of electrical activity simultaneously from hundreds of sites on the processes of single nerve cells, both in culture and in invertebrate ganglia. This method also provides a unique ability to detect activity in many individual neurons in an entire invertebrate ganglion controlling particular behavioral responses. The in-vitro activity of individual populations of neuronal elements (cell bodies, axons, dentrites or nerve terminals) at many neighboring loci in mammalian brain slices or isolated brain structures has been investigated. Recently dynamic patterns of electrical activity evoked in the intact vertebrate or mammalian brain by natural stimuli have also been monitored. By employing computerized optical recording and a display processor, video-displayed images of neuronal elements can be superimposed on the corresponding patterns of the optically detected electrical activity, thus allowing the spatio-temporal patterns of intracellular activity to be visualized in slow motion.