An autoradiographic study of the brainstem projections of vagal visceral afferent fibres in the domestic hen.

Using an autoradiographic technique, the central brainstem connections of vagal visceral afferent fibres were studied. The results show that there is a large projection of vagal afferent fibres to the ipsilateral nucleus of the tractus solitarius and a smaller, sparser projection to the contralateral nucleus of the tractus solitarius. That vagal afferent fibres across the mid-line via the commissural nucleus of Cajal is confirmed. In addition, a second, more rostrally placed decussation of vagal afferent fibres is shown. Associated with this more rostral decussation is an area of termination of vagal afferent fibres in the contralateral ventromedial reticular formation. No direct projection of vagal afferent fibres to the dorsal motor nucleus of the vagus was seen.