DEVELOPMENTAL PLASTICITY OF SELECTED SPINOCEREBELLAR AXONS - STUDIES USING THE NORTH-AMERICAN OPOSSUM, DIDELPHIS-VIRGINIANA

When the thoracic spinal cord of the opossum is hemisected at postnata l day 5 or 8, but not at day 12 or later ages, spinocerebellar axons w hich originate from spinal border cells, the sacral/coccygeal ventrola teral nucleus, and Stilling's nucleus grow through the lesion and reac h the cerebellum. The critical period for such growth is comparable to that reported previously for spinocerebellar axons originating within Clarke's nucleus and for axons of the fasciculus gracilis, but shorte r than that for most descending spinal axons. It appears, therefore, t hat differences exist in the ability of ascending and descending axons to traverse a lesion of their spinal pathway during development. (C) 1997 Elsevier Science B.V.