The inclusion criteria are: patients with AD (DSM IV) diagnosed less than two years, age between 50 and 65, with mild cognitive decline (MMSE between 20 and 24), and specific impairment of episodic memory (using the free and cued selective reminding test: FCSRT ), able to give and sign an informed consent. Patients with associated DSM I axis pathology, contra-indication to surgery or MRI, or preoperative MRI abnormalities will not be included. Five patients will be included in a 2-year period.