A FURTHER EVALUATION OF ORIGIN COURSE AND TERMINATION OF OPOSSUM CORTICOSPINAL TRACT

This study documents the granular postorbital, parietal and paramarginal origin of the opossum corticospinal tracts. The details of opossum cervical cord morphology were compared with what was previously described for the cat (Rexed 1952) and certain differences were noted. The opossum corticospinal tracts coursed in both the dorsal and lateral funiculi and ended in Rexed's laminae III through VI. The predominant areas of termination were the medial and, to a lesser extent, the lateral parts of laminae IV and V. Relatively few fibers terminated in lamina VI and the possible significance of this finding is discussed. Because of the interesting paucity of corticospinal bundles arising from the agranular preorbital area, the projections of this cortex were determined and briefly described. © 1968.