Optical Monitoring of Postsynaptic Potential in the Early Embryonic Avian Brain Stem Using a Voltage-Sensitive Dye

The ontogenetic approach to generation of physiological events during natural development would be a useful and powerful strategy for studying central nervous systems: it would allow us to analyse progressively the complicated functional organization and architecture of nervous systems, in a manner reminiscent of the expansion of a complex function in a power series. However, the experimental analysis of early embryonic nervous systems is technically difficult because the cells are extremely inaccessible: the microelectrode examination of neural cells, which provides the most direct test of their electrophysiology, is often difficult because of the small size of the cells. For this reason, electrophysiological studies of very early developing embryonic nervous systems have been hampered.