Heterozygote APPswe/PS1- E9 transgenic (TgAPP/PS1) founder mice (42) were provided by Dr. Borchelt at Johns Hopkins University (Baltimore, MD, USA). These mice were maintained by cross-breeding with the wild-type (WT, C57BL/6J) breeders, and resulting offspring were genotyped and used at the age indicated. For in vivo studies, young (6 months) and old (22 months) TgAPP/PS1 and age-matched WT mice (3– 4 in each treatment group) were fed for 1 month with a Purina “5001” basal diet (Dyets Inc., Bethlehem, PA, USA), supplemented with or without EGb 761 for an equivalent ad libitum daily intake of 100 mg/kg. For in vitro studies, day 14 WT mice embryonic brains were used. All animal handling and treatment were approved by the Institutional Animal Care and Use Committee.