Isolated dorsal root ganglion neurons in culture: Cytological maturation and extension of electrically active processes

Dissociated chick embryo dorsal root ganglion cells were maintained in vitro for long periods (up to 7 weeks) in cultures essentially free of nonneuronal cells. The cultured neurons attained an advanced stage of cytological maturity and extended long, highly branched processes which formed elaborate networks. Electrical activity was evoked and recorded extracellularly from these processes. Responses obtained from the processes of young (19–20 hr), fully isolated cells indicate that the ability to propagate action potentials is present very early in newly extended fibers and can be developed by neurons deprived of contact with any other cells. Complex responses evoked by single stimulus pulses suggest that many processes, especially in older cultures, contained more than a single active fiber.