Patterns of spontaneous bioelectric activity during maturation in culture of fetal rodent medulla and spinal cord tissues

Abstract

Microelectrode recordings in explants of fetal rodent medulla and spinal cord demonstrate that a variety of organotypic temporal patterns of spontaneous bioelectric discharges occur during maturation of these CNS tissues in culture. The spontaneous activities include repetitive barrages of spike potentials, as well as stereotyped slow‐waves. These discharges last up to several sec, and they may occur at regular intervals of the order of 1–10 sec, although activity patterns are often much more irregular. Some explants also show clear periodicity in the recurrence of phases of relative activity and inactivity, with cycle times ranging up to about 10 min. Correlations between the network excitability properties of the CNS tissues and their patterned spontaneous discharges were obtained by electrophysiologic analyses of responses to microelectrode stimulation.These complex, yet stereotyped, spontaneous bioelectric discharge patterns in cultures of organized CNS tissues show remarkable mimicry of rhythmic activities which occur in the embryonic CNS in situ, as determined by electrophysiologic and behavioral motility studies in the intact animal. Organotypic CNS explants provide, therefore, a valuable model system for further analyses of the cellular and molecular mechanisms underlying early development of behavior.