Christiana M. Leonard

Taste Pathways in Rat Brainstem

By means of a combination of electrophysiological and anatomical procedures, the projections of the anterior portion of the solitary nucleus were traced to the parabrachial nuclei in the pons, structures hitherto not considered to be included in the taste pathway. Responses to taste stimuli were recorded from this pontine area. Lesions in the pontine taste area resulted in degeneration of fibers reaching the lingual area in the thalamus.

The Connections of the Dorsomedial Nuclei

The connections of the mediodorsal nucleus were compared in rats, cats and monkeys. The medial portion receives from the olfactory cortex in rats, amygdala in cats, and amygdala and inferior temporal cortex in monkeys. In turn, the medial portion projects to sulcal cortex dorsal to the rhinal fissure in rats, and to orbitofrontal cortex in monkeys. The paralamellar portion of the mediodorsal nucleus receives from the cerebellum, superior colliculus and spinal cord and projects to the medial frontal area in rats and area 8 in monkeys. The lateral portion of the mediodorsal nucleus, well developed in monkeys, receives no known projections from subcortical regions and projects to the convexity of the frontal lobe.