Some olfactory pathways in the rabbit brain

Abstract The degeneration pattern in the rabbit following transection of the olfactory bulb or peduncle at various levels was studied by the Laidlaw method of Nauta. Degenerating axons were observed in the crossing of the anterior limb of the anterior commissure and in the lateral olfactory tract following olfactory bulb lesions which did not damage the anterior olfactory nucleus. Evidence was found for termination of the olfactory tract fibers over all parts of the anterior olfactory nucleus, the rostral and lateral parts of the olfactory tubercle, the anterior continuation of the hippocampus, the nucleus of the lateral olfactory tract, and the prepyriform areas 1, 2, and 3, the periamygdaloid areas 1, 2, part of 3, and 5, and the entorhinal axeas 1, 2, and 4 of Maximillian Rose. When the anterior olfactory nucleus was damaged degeneration was found in the contralateral olfactory bulb and anterior olfactory nucleus and parts of the ipsilateral neocortex adjacent to the rhinal fissure, limbic system (medial septal nucleus and anterior continuation of the hippocampus), pyriform lobe cortex, and lateral preoptic area. The results differ in particulars from those of previous investigators.