Optical studies of early developing cardiac and neural activities using voltage-sensitive dyes

Using optical methods for monitoring cellular electrical activity based on voltage-sensitive dyes, we have overcome several obstacles to the study of electrical function in the embryonic heart and central nervous system during early development. We have been able to monitor, for the first time, spontaneous electrical activity in the pre-fused cardiac primordia in early chick embryos at the 6- and early 7-somite stages of development and to follow the early development of electrical activity in the pre-contractile heart at the 7- to 9-somite stages. In addition, we have monitored neural responses in the early embryonic chick brain stem by optical means, and determined the spatial pattern of the response.