Learning and memory in nucleus basalis magnocellularis-lesioned rats after transplantation of fetal frontal cortex

The effect of fetal frontal cortex transplantation on behaviour performance was examined in adult male Wistar rats with lesions of the nucleus basalis magnocellularis (NBM). Compared to intact and sham-operated controls, the rats tested ten or twenty days after bilateral electrolytic lesions of NBM exhibited the significant learning and memory impairments (acquisition and performance of two-way active avoidance) whereas spontaneous motor activity was not significantly altered. The animals which received allotransplants of fetal frontal cortex (from 18-day gestational rat fetuses) into NBM, two ("early" transplantation-NBM-ET) or ten ("delayed" transplantation-NBM-DT) days after lesioning, respectively, manifested the complete amelioration of noticed impairments when tested ten days after transplantation procedure. Corresponding sham-transplants groups (NBM-SET and NBM-SDT) showed only slightly improvement of acquisition but not performance of two-way active avoidance. The ability of the transplants to restore learning and memory in the NBM lesioned rats suggests that graft of fetal frontal cortex can functionally influence neuronal activity of the lesioned host brain.