Olivary projections from the mesodiencephalic structures in the cat studied by means of axonal transport of horseradish peroxidase and tritiated amino acids

Abstract

By means of horseradish peroxidase (HRP) and autoradiographic methods, olivary projections from mesodiencephalic structures were studied in the cat. Following HRP injections in various parts of the inferior olive, many cells were labeled ipsilaterally in the nucleus of Darkschewitsch, the nucleus accessorius medialis of Bechterew, the nucleus of the fields of Forel, and the subnucleus dorsomedialis and ventrolateralis of the parvocellular red nucleus. Some labeled cells also occurred ipsilaterally in the suprarubral reticular formation and a few labeled cells in the interstitial nucleus of Cajal. After injection of tritiated amino acids in different parts of the mesodiencephalic region mentioned above, labeled fibers were found in different parts of the inferior olive, presenting a high degree of the topographic correlation within the mesodiencephalo-olivary projection, which was exclusively ipsilateral. That is, the nucleus of Darkschewitsch was found to project to the rostral half of the medial accessory olive and the dorsomedial cell column. There was mediolateral topographic relation in this projection. The nucleus accessorius medialis of Bechterew was found to project to the ventral lamella and the lateral part of the dorsal lamella as well as to small rostromedial part of the caudal half of the medial accessory olive. The subnucleus dorsomedialis and ventrolateralis of the parvocellular red nucleus projected to the rostral and caudal halves, respectively, of the medial part of the dorsal lamella. The subnucleus ventrolateralis of the parvocellular red nucleus also sent fibers to the lateral part of the ventrolateral outgrowth. The nucleus of the fields of Forel, suprarubral reticular formation, and interstitial nucleus of Cajal appeared to project to the caudal half of the medial accessory olive, the medial part of the ventrolateral outgrowth, the rostral part of the dorsal cap, and the caudal part of the dorsal accessory olive.

Spatial organization of premotor neurons related to vertical upward and downward saccadic eye movements in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) in the cat

“…These descending axons presumably are destined for targets in the posterior brainstem and/or spinal cord. Neurons in the region of the field H of Forel, including the riMLF, have descending efferent projections to the lower brainstem, including the pontomedullary reticular formation (nucleus reticularis pontis caudalis and nucleus reticularis gigantocellularis; Isa et al, 1988b;Isa and Itouji, 1992;Isa and Sasaki, 1992a;Shiraishi and Nakao, 19941, the inferior olivary nucleus Courville, 1981, 1982;Onodera, 1984;Spence and SaintCyr, 1988a;Isa and Sasaki, 1992a), and the vestibular complex (Spence and Saint-Cyr, 1988a,b;Isa and Sasaki, 1992a). The riMLF and, more generally, the field H of Forel also project to the cervical spinal cord (Isa et al, 1988a,b;Holstege, 1988;Spence and Saint-Cyr, 1988a;Holstege and Cowie, 1989;Isa and Itouji, 1992;Isa and Sasaki, 1992a,b;Robinson et al, 1994), specifically targeting biventer cervicis and complexus motoneurons that are related to head movement (Isa et al, 1988a;Isa and Sasaki, 199213).…”

Molecular, Topographic, and Functional Organization of the Cerebellar Cortex: A Study with Combined Aldolase C and Olivocerebellar Labeling

“…8 B). In group I, the v-PO, d-PO, r-MAO, and subnucleus a receive input from the cerebral cortex relayed by nuclei in the mesodiencephalic junction (Swenson and Castro, 1983;Onodera, 1984;Holstege and Tan, 1988;de Zeeuw, 1989) (Fig. 8 B, green arrows), although the subnucleus a also receive input from the spinal cord (Matsushita et al, 1991).…”

“…Concerning group III, the subnucleus b of the MAO receives heterogeneous input from the spinal cord and dorsal column nuclei with crude somatotopy (Boesten and Voogd, 1975;Berkley and Hand, 1978;Matsushita et al, 1992;Molinari et al, 1996) and from the vestibular nuclei and the mesodiencephalic junction (Swenson and Castro, 1983;Onodera, 1984;Gerrits et al, 1985) ( Fig. 8 B, ocher arrow).…”

Accessory Oculomotor Nuclei of Man

“…1984] while the ND efferent outputs had their major target field in the medial accessory olive [Saint-Cyr and Courville. 1982;Onodera, 1984], More recently, in the cat afferent projec tions from the pericruciate cortex and the deep cerebellar nuclei were demonstrated as ending inside the ND over lapping in areas of the ND which in turn projected back to the cortex. It was thus suggested that the ND played an integrative role in these circuits [Rutherford et al.…”