Primary connections of the anterior and posterior lateral line nerves in the oyster toadfish.

This study used anterograde transport of horseradish peroxidase to identify primary projections of the anterior and posterior lateral line nerves in the oyster toadfish, Opsanus tau. Both lateralis nerves project to the nucleus medialis and nucleus caudalis, which comprise a continuous lateralis cell column. Separation between nucleus medialis and nucleus caudalis is based on cell type and position. Unlike the primitive condition, the nuclei are not obviously separable on the basis of gross topography. The anterior lateral line nerve projects to the ventral area, and the posterior lateral line nerve projects to the dorsal area of the lateralis cell column. Anterior lateral line nerve projections to nucleus medialis terminate in a larger area than do projections from the posterior lateral line nerve, suggesting that more lateralis information enters from the head than from the trunk and tail. This speculation is reasonable considering the animal's large head and sedentary bottom existence. Both lateral line nerves project to the nucleus magnocellularis and the eminentia granularis, but only projections from the posterior lateral line nerve were seen in the granular layer of the cerebellum.