1. A method comprising administering to a subject having Alzheimer's disease with impaired long-term potentiation, a gene transfer vector comprising a nucleic acid sequence encoding an exogenous prohibitin, wherein said gene transfer vector is administered to said subject by injection to the hippocampus, and wherein said gene transfer vector expresses the exogenous prohibitin in the hippocampus of the subject, thereby treating said Alzheimer's disease with impaired long-term potentiation.