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Reticulospinal fibers of the opossum, Didelphis virginiana I. Origin
Author(s) -
Beran Robert L.,
Martin George F.
Publication year - 1971
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901410404
Subject(s) - anatomy , pons , reticular formation , biology , chromatolysis , medulla oblongata , nissl body , reticular connective tissue , spinal cord , tegmentum , medial longitudinal fasciculus , cytoarchitecture , nucleus , opossum , marsupial , neuroscience , central nervous system , midbrain , staining , genetics , paleontology
Complete and partial cervical cord hemisections were placed at different levels according to a modification of the Gudden method (Brodal, '40), as applied to the opossum. Nissl staining techniques were employed and either acute retrograde cellular change of cell loss was studied following 7to 65 day survival periods. The results of a previous cytoarchitectonic study which followed the terminology of Meessen and Olszewski ('49) and Olszewski and Baxter ('54) served as controls. Chromatolysis or cells loss was found in medium‐sized (20–29 μ), large (30–44 μ) and giant (45–60 μ) cells in the pontine and medial medullary reticular formation. Retrograde changes in the pontine reticular formation were found in the nucleus pontis centralis oralis, the nucleus pontis centralis caudalis and the rostral nucleus gigantocellularis. Within the pons, chromatolysis was particularly evident in the large and giant cells. Following cervical cord lesions, the medullary reticular formation contained chromatolytic neurons within the nucleus gigantocellularis, the nucleus paragigantocellularis dorsalis, the paramedian reticular nucleus and the nucleus interfascicularis hypoglossi. At pontine levels, chromatolytic cells were present mainly on the side of the lesion. However, cells were found to have undergone retrograde changes in specific areas of the contralateral side. Although the greatest number of reactive cells within the medullary reticular formation were also located on the side of the lesion, there was more contralateral involvement than was the case in the pons.