Neural origin of cardioperiodicities in Limulus

Abstract

The heart rate of chronically monitored Limulus frequently shows a 3- to 5-min periodicity. Exploration of the neural bases of this cyclical activity was difficult because surgical exposure usually resulted in its permanent disappearance. However, in a recent series of studies involving over 200 animals the periodicity was found to persist after surgery in three preparations. The results of various lesions showed that while the supraesophageal and abdominal ganglia may influence the duration of the periodicity, its continuation is dependent upon dorsal nerves 7 and 8 and the postesophageal ganglia from which they emerge.