The Organization of the Olivocerebellar Projection in the Chicken

Abstract

The olivocerebellar pathway in the chicken was studied, using the horseradish peroxidase retrograde tracing technique. The inferior olivary nuclear complex (IOC) of the chicken comprises a dorsal and a ventral lamella and projects to the contralateral cerebellar hemisphere. In this paper the organization of the olivocerebellar pathway in the chicken is compared with the mammalian olivocerebellar pathway. The present results, taken in conjunction with data on the embryogenesis of the rat IOC, suggest that the avian dorsal lamella represents, from lateral to medial, the dorsal olivary nucleus, the principal olivary nucleus, and the rostral and a small part of the caudal medial nucleus (MO) of mammals, while the ventral lamella represents a larger part of the caudal MO of mammals.

Domain-specific olivocerebellar projection regulated by the EphA-ephrin-A interaction

“…Previous studies have revealed that the axons of IO neurons project to Purkinje cells in the contralateral side of the cerebellum, with at least two overlapping patterns. First, IO axons are organized along the rostrocaudal axis of the cerebellum (Furber, 1983;Furber and Watson, 1983). In chicken, neurons in the rostromedial IO project to the caudal cerebellum, while neurons in the caudolateral IO project to the rostral cerebellum Furber, 1983).…”

“…First, IO axons are organized along the rostrocaudal axis of the cerebellum (Furber, 1983;Furber and Watson, 1983). In chicken, neurons in the rostromedial IO project to the caudal cerebellum, while neurons in the caudolateral IO project to the rostral cerebellum Furber, 1983). Second, discrete areas of the IO project to different domains in the cerebellar cortex that are aligned mediolaterally (parasagittal domains) (BuisseretDelmas and Angaut, 1993).…”

Accessory Optic System and Pretectum of Birds: Comparisons with those of other Vertebrates (Part 2 of 2)

“…A direct bilateral mossy fiber projection originating from the nBOR distributes to folia IXc, d and the paraflocculus; an indirect climbing fiber projection which arrives via the dorsal division of the medial accessory olive distributes to folia IX and X [Arm strong and Clarke, 1979;Freedman et al, 1977;Furber, 1983]. This portion of the cerebellum also receives afferents from the vestibular nuclear complex [Freed man et al, 1977;Harkmark, 1956;Whit lock, 1952].…”

A Quantitative Study of the Purkinje Cells in the Cerebellum and the Inferior Olivary Neurons in the Chicken

“…It has been believed on the basis of the morphological appearance that the ventral lamella corresponds to the PO, and the lateral and medial parts of the dorsal lamella are the homologue of the DAO and MAO, respectively [12]. Recently, it is suggested that the chicken dorsal lamella represents the DAO, PO, and the rostral and a small part of the caudal MAO, while the ventral lamella represents most of the caudal MAO on the basis of the olivocerebellar projection [10].Purkinje cells (PCs) are known to receive double inputs from the mossy and climbing fibers. An olivocerebellar fiber gives off several climbing fibers, but each Purkinje cell receives only one climbing fiber [6].…”

“…Contrary to our expectation, the DAO (namely, the dorsal lamella) in the classical interpretations was largest, and the MAO was similar in neuronal number to the PO in this study. The subdivisions of the chicken IOC that are suggested by Furber [10] in term of the olivocerebellar projection, however, are suitable for this study.…”