LONG-TERM-MEMORY RETRIEVAL DEFICITS OF LEARNED TASTE-AVERSIONS ARE AMELIORATED BY CORTICAL FETAL BRAIN IMPLANTS

In this study, the effects that fetal brain implants have on the abili ty to retrieve the memory for a previously acquired conditioned taste aversion (CTA) in insular cortex (IC) lesioned rats were tested. Sever al groups of rats were trained for a CTA, were lesioned in the IC 4 da ys later, were implanted with different fetal cortical tissues, were t reated or untreated with nerve growth factor (NGF), and then were test ed for recall either 15 or 45 days later. Rats were then retrained and tested with a different taste and in the inhibitory avoidance (IA) ta sk. All implanted animals recovered the retrieval of CTAs learned befo re IC lesions; however, only the homotopic IC implants at 45 days or N GF supplemented at 15 days induced recovery of the ability to learn CT A. The latter effect was also true for IA learning. The results sugges t that the brain mechanisms for recovery of memory functions are diffe rent from those of learning abilities.