Improvement of auditory discrimination learning by Ginkgo biloba extract EGb 761®

The effect of oral application of Ginkgo biloba extract EGb 761® on auditory discrimination learning in Mongolian gerbils was investigated using discrimination tasks with three different degrees of difficulty and two protocols for administration starting 2 weeks prior to or at the beginning of training. In comparison to placebo-treated controls we observed significant improvement of learning performance in EGb 761® treated gerbils in discrimination tasks of all degrees of difficulty, from the easiest to the most demanding. EGb 761® has been reported to increase the extracellular concentration of dopamine in prefrontal cortex of rats which plays a major role in the type of discrimination learning used in the present study. We, therefore, suppose that EGb 761® improves discrimination learning through its effect on the dopaminergic system.