The successful grafting of homotopic tissue (see Table 1 for terminology), ie neuronal tissue,
to the brain has recently increased the interest in the brain as an immunologically privileged
transplantation site. Evidence accumulated over the past decade has demonstrated that
under optimal conditions neuronal grafts seem to be able to survive indefinitely. It appears
that they become integrated with the host brain to the extent that they form synaptic
connections, and normalize behavioral and biochemical changes due to prior experimental …