Afferent projections to the deep mesencephalic nucleus in the rat

Journal Article · Sun Jan 10 04:00:00 EST 1982 · J. Comp. Neurol.; (United States)

DOI:https://doi.org/10.1002/cne.902040204· OSTI ID:5464935

Veazey, R B; Severin, C M

Afferent projections to the deep mesencephalic nucleus (DMN) of the rat were demonstrated with axonal transport techniques. Potential sources for projections to the DMN were first identified by injecting the nucleus with HRP and examining the cervical spinal cord, brain stem, and cortex for retrogradely labeled neurons. Areas consistently labeled were then injected with a tritiated radioisotope, the tissue processed for autoradiography, and the DMN examined for anterograde labeling. Afferent projections to the medial and/or lateral parts of the DMN were found to originate from a number of spinal, bulbar, and cortical centers. Rostral brain centers projecting to both medial and lateral parts of the DMN include the ipsilateral motor and somatosensory cortex, the entopeduncular nucleus, and zona incerta. at the level of the midbrain, the ipsilateral substantia nigra and contralateral DMN likewise project to the DMN. Furthermore, the ipsilateral superior colliculus projects to the DMN, involving mainly the lateral part of the nucleus. Afferents from caudal centers include bilateral projections from the sensory nucleus of the trigeminal complex and the nucleus medulla oblongata centralis, as well as from the contralateral dentate nucleus. The projections from the trigeminal complex and nucleus medullae oblongatae centralis terminate in the intermediate and medial parts of the DMN, whereas projections from the contralateral dentate nucleus terminate mainly in its lateral part. In general, the afferent connections of the DMN arise from diverse areas of the brain. Although most of these projections distribute throughout the entire extent of the DMN, some of them project mainly to either medial or lateral parts of the nucleus, thus suggesting that the organization of the DMN is comparable, at least in part, to that of the reticular formation of the pons and medulla, a region in which hodological differences between medial and lateral subdivisions are known to exist.

• Research Organization: Department of Anatomy and Neurobiology, Washington University of Medicine, St. Louis, Missouri
• OSTI ID: 5464935
• Journal Information: J. Comp. Neurol.; (United States), Journal Name: J. Comp. Neurol.; (United States) Vol. 204:2; ISSN JCNEA
• Country of Publication: United States
• Language: English

Related Subjects

550801* -- Morphology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
AUTORADIOGRAPHY
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
CEREBRAL CORTEX
CEREBRUM
HISTOLOGY
LABELLED COMPOUNDS
MAMMALS
NERVE CELLS
NERVE TISSUE
NERVOUS SYSTEM
ORGANS
RATS
RODENTS
SOMATIC CELLS
SPINAL CORD
TISSUES
TRITIUM COMPOUNDS
VERTEBRATES