Biomaterial Database

Cerebellar efferents in the lizard Varanus exanthematicus. II. Projections of the cerebellar nuclei. 1984

G C Bangma, and H J ten Donkelaar, and P J Dederen, and R de Boer-van Huizen

The projections of the cerebellar nuclei have been studied in the lizard Varanus exanthematicus with various experimental anatomical techniques. In anterograde degeneration experiments (lesions of the cerebellar peduncle) both ascending and decending contralateral projections were found. Ascending fibers which could be traced from the cerebellar commissure ventralward decussated at the level of the trochlear and oculomotor nuclei. These fibers coursed rostralward to the mesodiencephalic junction. With anterograde tracing techniques (3H-leucine and HRP) this tract was found to terminate in the nucleus ruber and the interstitial nucleus of the fasciculus longitudinalis medialis. Moreover, retrograde tracer studies (HRP, "Fast Blue") showed that this tract appeared to arise mainly in the lateral cerebellar nucleus. With both anterograde degeneration and tracing techniques (3H-leucine and HRP) a bundle of fibers could be followed, which decussates in the basal part of the cerebellum and passes dorsally around the contralateral medial cerebellar nucleus to the lateral side of the brainstem. This contralaterally descending projection system was found, lateral to the vestibular nuclear complex, and as far caudally as the descending vestibular nucleus, to terminate on various vestibular nuclei. Horseradish peroxidase studies showed that this contralaterally descending projection system originates mainly in the medial cerebellar nucleus, but ipsilaterally descending projections were also found. With the fluorescent double labeling technique ("Fast Blue" and "Nuclear Yellow") the projections of the cerebellar nuclei described above were confirmed. Furthermore, double labeling revealed neurons in both cerebellar nuclei (especially the medial nucleus) that project to both the mesencephalon and the cervical spinal cord. The present results indicate that the efferent connections of the cerebellar nuclei in the lizard Varanus exanthematicus are organized as two main projections, an ascending projection comparable to the mammalian brachium conjunctivum arising in the lateral cerebellar nucleus, and a descending projection comparable to the mammalian hook bundle (fasciculus uncinatus), originating mainly in the medial cerebellar nucleus. Such projections are common for terrestrial vertebrates.

UI	MeSH Term	Description	Entries
D008116	Lizards	Reptiles within the order Squamata that generally possess limbs, moveable EYELIDS, and EXTERNAL EAR openings, although there are some species which lack one or more of these structures.	Chameleons,Geckos,Chameleon,Gecko,Lizard
D008322	Mammals	Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.	Mammalia,Mammal
D008636	Mesencephalon	The middle of the three primitive cerebral vesicles of the embryonic brain. Without further subdivision, midbrain develops into a short, constricted portion connecting the PONS and the DIENCEPHALON. Midbrain contains two major parts, the dorsal TECTUM MESENCEPHALI and the ventral TEGMENTUM MESENCEPHALI, housing components of auditory, visual, and other sensorimoter systems.	Midbrain,Mesencephalons,Midbrains
D011689	Purkinje Cells	The output neurons of the cerebellar cortex.	Purkinje Cell,Purkinje Neuron,Purkyne Cell,Cell, Purkinje,Cell, Purkyne,Cells, Purkinje,Cells, Purkyne,Neuron, Purkinje,Neurons, Purkinje,Purkinje Neurons,Purkyne Cells
D012012	Red Nucleus	A pinkish-yellow portion of the midbrain situated in the rostral mesencephalic tegmentum. It receives a large projection from the contralateral half of the CEREBELLUM via the superior cerebellar peduncle and a projection from the ipsilateral MOTOR CORTEX.	Nucleus Ruber,Nucleus, Red
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002529	Cerebellar Nuclei	Four clusters of neurons located deep within the WHITE MATTER of the CEREBELLUM, which are the nucleus dentatus, nucleus emboliformis, nucleus globosus, and nucleus fastigii.	Dentate Nucleus,Nucleus Dentatus,Nucleus Emboliformis,Nucleus Fastigii,Nucleus Globosus,Amiculum of the Dentate Nucleus,Anterior Interposed Nucleus,Anterior Interpositus Nucleus,Central Nuclei,Deep Cerebellar Nuclei,Dentate Cerebellar Nucleus,Fastigial Cerebellar Nucleus,Fastigial Nucleus,Intracerebellar Nuclei,Lateral Cerebellar Nucleus,Medial Cerebellar Nucleus,Central Nucleus,Cerebellar Nuclei, Deep,Cerebellar Nucleus,Cerebellar Nucleus, Deep,Cerebellar Nucleus, Dentate,Cerebellar Nucleus, Fastigial,Cerebellar Nucleus, Lateral,Cerebellar Nucleus, Medial,Deep Cerebellar Nucleus,Emboliformis, Nucleus,Fastigii, Nucleus,Globosus, Nucleus,Interposed Nucleus, Anterior,Interpositus Nucleus, Anterior,Intracerebellar Nucleus,Nuclei, Central,Nuclei, Cerebellar,Nuclei, Deep Cerebellar,Nuclei, Intracerebellar,Nucleus Fastigius,Nucleus, Anterior Interposed,Nucleus, Anterior Interpositus,Nucleus, Central,Nucleus, Cerebellar,Nucleus, Deep Cerebellar,Nucleus, Dentate,Nucleus, Dentate Cerebellar,Nucleus, Fastigial,Nucleus, Fastigial Cerebellar,Nucleus, Intracerebellar,Nucleus, Lateral Cerebellar,Nucleus, Medial Cerebellar
D004027	Diencephalon	The paired caudal parts of the PROSENCEPHALON from which the THALAMUS; HYPOTHALAMUS; EPITHALAMUS; and SUBTHALAMUS are derived.	Interbrain,Interbrains
D004525	Efferent Pathways	Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.	Motor Pathways,Efferent Pathway,Pathway, Efferent,Pathways, Efferent
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia