The morphology of cricket giant interneurons

Abstract

Abstract Axonal iontophoresis of cobalt chloride was used to describe the morphology of the seven largest interneurons in the abdominal nervous system of the cricket Acheta domesticus. The somata of these neurons are all found in the terminal (5th) abdominal ganglion. This ganglion is derived from four primitive segmental ganglia (the 7th–10th primitive segments) and the morphology of the interneurons within this ganglion suggests that the neurons are derived from different primitive segments. Furthermore, some of the neurons appear to be serially homologous elements. Three aspects of the morphology support these suggestions: (1) soma position, (2) relative positions of commissural processes, and (3) the general shape and extent of dendritric fields.