Hippocampal Projections and Related Neural Pathways to the Mid-Brain in the Cat

Recent studies in the rat (Guillery, 1956; Nauta, 1956) have confirmed much earlier descriptions of widespread distributions of the fornix system to the diencephalon and the rostral mid-brain regions. Besides the well-known massive hippocampal projections to the septal region (Ganser, 1882) and the mammillary body (Gudden, 1881), fornix components have been traced from the hippocampus to the preoptic region and the hypothalamus (Cajal, 1911), to the anterior nuclear complex and rostral intralaminar nuclei of the thalamus (Gudden, 1881; Vogt, 1898; Cajal, 1911), and to the rostral part of the central grey mid-brain substance (Edinger and Wallenberg, 1902).