GINSENG IMPROVES STRATEGIC LEARNING BY NORMAL AND BRAIN-DAMAGED RATS

ADULT rats were prepared with either sham or medial prefrontal cortex lesions and administered, beginning on the third post-operative day, e ither, 0, 40, or 80 mg kg(-1) crude ginseng extract suspended in salin e daily for the next 30 days. Later, kinetic functions were evaluated on an elevated rotating rod. No long-term influences of the treatments were observed on this task. Significant positive influences of ginsen g were observed in the position reversal task. The learning deficits o bserved in the saline control brain-damaged rats were significantly at tenuated in the ginseng-treated animals. An analysis of trial 2 respon se accuracy across reversals revealed enhanced cognitive abilities (i. e. acquisition of a win-stay, lose-shift strategy) in both the brain d amaged and sham control rats administered ginseng. Generally, administ ration of the higher dose resulted in better performance in the learni ng paradigm. The exact mechanism responsible for these promising resul ts remains to be discovered. Several possible mechanisms are discussed . (C) 1998 Rapid Science Ltd.