Panax ginseng extract improves the performance of aged Fischer 344 rats in radial maze task but not in operant brightness discrimination task.

The effect of Panax ginseng extract on the learning performance of aged Fischer 344 rats using the 8-arm radial maze task and the operant discrimination task was examined. Aged rats showed significantly impaired learning performance in both tasks. Daily administration of ginseng extract (8 g/kg/d, p.o. for 12-33 d) ameliorated the impairment of learning performance in the radial maze task but not in the operant discrimination task. These results suggest that subchronic treatment with ginseng extract improves spatial cognitive impairment in aged rats.