Winter (22) reported that mice treated with Ginkgo biloba leave extract
at 100 mg/kg orally for 4–8 weeks resulted in improved memory and learning
during appetitive operant conditioning. Rats dosed with Ginkgo biloba leave
extract at 100 mg/kg per day, p.o., for 4 to 8 weeks prior to training and then
for an additional 10 weeks resulted in reduced time to acquisition of tasks and
enhanced retention performance (22). Cohen-Salmon et al. (23) also showed that
EGb 761 (40 mg/kg ip for 1–3 weeks) enhanced learning in young (6 months
old) and aging (22 months old) Swiss mice.