BEHAVIORAL CONSEQUENCES OF FRONTAL-CORTEX GRAFTS AND ENRICHED ENVIRONMENTS AFTER SENSORIMOTOR CORTEX LESIONS

Past studies have experienced difficulty in achieving graft survival a nd behavioural recovery after sensorimotor cortex lesions, In the pres ent work, adult female rats trained preoperatively to cross a narrow b eam for food reward were maintained in standard group cages or an enri ched environment, commencing one week after a unilateral lesion, One m onth post-lesion, half of these rats received multiple suspension graf ts of (E20) fetal frontal cortex, placed adjacent to the lesion cavity , and 8 days later recovery of beam-walking skills was examined for a six-week period, The grafts survived in all cases with an appropriate lesion, a notable result given the one month lesion-graft delay, but g raft volume was not influenced by postoperative environment, The subst antial lesion-induced deficits evident just prior to differential hous ing showed a marked reduction by the start of post-graft testing, but relative to intact controls a persistent deficit in foot slip errors o ccurred in all lesion groups, Irrespective of graft status, postoperat ive enrichment prevented the occurrence of severe foot slips, especial ly early in retraining, The frontal grafts, however, enhanced beam-wal king recovery by reducing the overall frequency of foot slips on early post-grafting sessions, an effect we suggest is related to graft-deri ved trophic influences, but this measure was not significantly improve d by postoperative enrichment.