The acousticolateral area of bony fishes and its cerebellar relations.

Abstract

The acousticolateral area of fishes containsa vestibular area and a lateral line area. The vestibular area appears to be very constant with respect to its internal structure, its input, and its relation to the lateral line area. It is more difficult to understand the lateral line area, since this region appears to undergo greater evolutionary modification in various families of fish. The most consistent analysis to date subdivides the acousticolateral area into a nucleus medialis (ant. lobe) and a nucleus dorsalis (post. lobe), but this may be modified when further experimental data becomes available. The vestibulolateral lobe of the cerebellum is, as Larsell already indicated, closely related to the acousticolateral area. This cerebellar region contains an eminentia granulans aligned with the nucleus medialis, and an auricle (lobus caudalis) aligned with the nucleus dorsalis. The molecular layer of the vestibulolateral lobe of the cerebellum continues as the crista cerebellaris of the acousticolateral area; our data for the weakly electric fish indicates that the crista cerebellaris contains: (1) axons of interneurons of the acousticolateral area, and (2) vestibulolateral efferents organized as parallel fibers. Direct afferent input from the lateral line to the crista cerebellaris may be an uncommon specialization.