The vestibular nuclei in the domestic hen (Gallus domesticus). II. Primary afferents.

Lesions of the vestibular ganglion in the domestic hen have been made by mechanical damage and thermocoagulation, and the resulting degeneration of the proximal vestibular nerve fibers has been studied in Fink-Heimer9, Nauta18 and Eager8 sections of the brain stem. The vestibular nerve fibers were found to terminate within central regions of the superior nucleus, in the cell group A, the nucleus Deiters ventralis, the nucleus tangentialis, the cell group B, the dorsomedial part of the medial nucleus and the descending nucleus. The nucleus Deiter dorsalis does not receive vestibular nerve afferents. The findings are discussed in the light of the structural organization and physiology of the vestibular nuclear complex in birds and compared with the organization of the nuclear complex in mammals.