Transplantation of septal neurons maintained in long-term culture.

Septal cells were maintained in culture for varying lengths of time and then transplanted to adult hippocampi from which the native septal input had been removed. Cells grafted after 1 week in culture survived transplantation to the brain and innervated the host hippocampus in a pattern comparable to the native cholinergic projection. Cells grafted after 2 weeks in culture did not survive in the brain, but did survive re-plating. In addition, the viability of cells transplanted from culture paralleled the viability of brain tissue taken from donors of equivalent ages, suggesting that changes which occur in culture and affect the viability of transplanted neurons may also occur during normal development.