RECOVERY OF TASTE-AVERSION LEARNING INDUCED BY FETAL NEOCORTEX GRAFTS- CORRELATION WITH IN-VIVO EXTRACELLULAR ACETYLCHOLINE

Rats showing disrupted taste aversion due to insular cortex lesions, r eceived either homotopic or heterotopic (occipital) cortical fetal bra in grafts. Behavioral results showed that the recovery of the ability to acquire conditioned taste aversions induced by fetal grafts depende d on post-graft time (45 but not at 15 days) and tissue specificity (h omotopic but not heterotopic). In vivo analysis of acetylcholine (ACh) release revealed that only the group receiving homotopic grafts and t ested 45 days post graft had a release of ACh after KCI stimulation si milar to that in the control group. Furthermore, homotopic grafts and lesioned groups showed significantly weaker specific receptor binding of [H-3]L-glutamate compared with controls. These results suggest that ACh is specifically involved in the process of behavioral recovery in duced by homotopic cortical transplants.