Implantation of embryonic neural tissue into the central nervous system (CNS) can be either in the form of solid pieces or as a dissociated cell suspension; The latter approach has several advantages as the preferred mode of transplantation into the CNS: The tissue can be placed directly into any site within the brain (including deep subcortical sites not accessible for solid grafting), without the need for any additional steps to ensure a special vascularization of the transplants (e.g., previous cavitation); multiple grafts can be placed within any individual animal/patient; the co-grafting of several tissue types is more easily realized using this technique; and suspension grafts enable an assessment to be made of the number and viability of cells being implanted.