[The behavior of embryonic nerve cells transplanted into the brain]

Small solid pieces of 3H-thymidine labeled rat neocortex at day 20 of embryonic development were transplanted homotopically into the cortex of adult rats. Transplanted cells migrated from the site of implantation into cortical layers 2-4 of the host to the distance of about 1 mm. No labeled neurons was found in cortical layers 5-6 (the target site during their normal migration). Migration of glial cells was similar to that of astrocytes moving from the suspension grafts. In some cases, similar distribution of migrating donor cells around the implantation site was observed despite the fact that a solid grafted tissue was absent.