Ventral Lamella Of Principal Olive Research Articles

Difference of climbing fiber input sources between the primate oculomotor-related cerebellar vermis and hemisphere revealed by a retrograde tracing study

The cerebellar flocculus–paraflocculus complex, vermal lobule VII (V-7) and hemispheric lobule VII (H-7) are involved in learning-dependent smooth pursuit eye movement control. To locate the sources of climbing fiber inputs to the H-7 and V-7, we injected retrograde tracers and examined the locations of retrogradely labeled neurons in the inferior olive in 4 monkeys. After the injection of cholera toxin B (CTB) into the H-7, retrogradely labeled neurons were observed abundantly in cell group d, i.e., dorsal cap, of the caudal medial accessory olive (MAO) and ventral lamella of principal olive (PO). After injections of fast blue (FB) into the V-7, retrogradely labeled neurons were observed mainly in cell group b of MAO, but rarely in cell group d or PO. Cell group d is known to receive inputs from the nucleus optic tract (NOT) and project climbing fibers to the flocculus and ventral paraflocculus, and cell group b is known to receive inputs from the superior colliculus. These results suggest that the three oculomotor cerebellar areas may use different visual signals for the control of smooth pursuit: the flocculus–paraflocculus complex and H-7 receive visual climbing fiber inputs derived mainly from the NOT via cell group d, while the V-7 receive visual climbing fiber inputs derived mainly from the superior colliculus via cell group b.

Morphological study on the inferior olivary nuclear complex of the donkey ( Equus asinus)

This study provides basic data on the normal structure of the inferior olivary complex (IOC) of the donkey, Equus asinus, at the light microscopic level. In common with that of other mammals, the donkey IOC consisted of three major nuclei and four minor groups of cells. The former was comprised of the medial and dorsal accessory olives (MAO and DAO, respectively) and the principal olive (PO), and the latter was comprised of the dorsal cap, nucleus β, ventrolateral outgrowth and dorsomedial cell column. The MAO had the longest rostral to caudal representation and formed the caudal pole of IOC. The DAO was located dorsally to the MAO in the caudal half of the IOC. In the rostral half, the DAO bended ventrally and merged with the dorsal lamella of PO. More rostrally, the DAO lost its connection with the dorsal lamella and then conversely connected with the ventral lamella of PO. The DAO formed the rostral pole of the IOC. The PO extended through the rostral half of the IOC. The dorsal cap was a small group of cells. Overall, the donkey IOC is similar to that of other mammals.

Projections to the inferior olive of the cat. II. Comparisons of input from the gracile, cuneate and the spinal trigeminal nuclei.

The present experiments compared the projections to the inferior olive of the cat from the gracile, cuneate and spinal trigeminal nuclei. A differential labeling strategy was used for these comparisons. It was found that all three somatic sensory nuclei project to portions of all three major divisions of the contralateral inferior olive. The spinal trigeminal n. may also project less densely to the ipsilateral medial accessory olive. Projections to the dorsal accessory nucleus (DAO) and the medially-adjacent ventral lamella of the principal nucleus are roughly somatotopically organized. Although there is considerable overlap between the projection zones, the gracile n. projects predominantly to lateral DAO, the cuneate n. projects predominantly to medial DAO, and the spinal trigeminal nucleus pars caudalis projects predominantly to the most medial portions of DAO and the ventral lamella of principal olive. Projections to the medial accessory olive, on the other hand, are not as highly organized. Instead, they overlap extensively within a small egg-shaped area in the middle of the caudal half of the nucleus. Whereas all portions of the gracile and cuneate nuclei project to the inferior olive, only the pars caudalis of the spinal trigeminal nucleus appears to do so. These results were compared with the three available olivocerebellar maps as well as with the available behavioral and electrophysiological evidence on cerebellar somatotopic organization. This comparison indicated that the inputs to the cerebellum from the three second-order somatosensory nuclei via the inferior olive appear to be generally consistent with cerebellar somatotopic organization. This consistency is apparent not only with respect to the longitudinally-organized, vermal and paravermal differences in the anterior lobe, but also with respect to the transversely-organized specific somatotopy of the intermediate zone of the anterior lobe and the paramedian lobule.