Unlike previous studies indicating that OLE can improve synaptic plasticity in the dentate gyrus of the rat hippocampus, thus attenuating Alzheimer’s disease-like pathology [68], the present study indicated that either chronic or subacute treatment of WT mice with OLE at the given dose did not up-regulate the effect on BDNF and TrkB in their hippocampus; however, subacute OLE increased the synthesis of NT4/5 in this brain region. Here, BDNF is linked to early-onset autosomal dominant Alzheimer disease.