Emotion and Attention in Alzheimer's Disease (ATEMMA)

Inclusion Criteria: * Healthy volunteers : * Affiliation to social security * Medical examination before study participation * No contraindication to MRI * Informed consent signed * Young adults older than 18 years and younger than 40 years * Healthy old adults older than 65 years and younger than 95 years * Visual acuity allowing normal perception of stimuli or corrected to normal vision * Patients with Alzheimer's Disease : * Affiliation to social security * Medical examination before study participation * No contraindication to MRI * Informed consent signed * Patients with Alzheimer's Disease at mild or moderate stage (National Institute on Aging and Alzheimer's Association criteria), diagnosed at Grenoble CMRR (Centre Mémoire de Ressources et de Recherche) * Patients older than 65 years and younger than 95 years * MMSE (Mini-Mental State Examination) \> 18/30 * Ability to understand study instructions and give an informed consent * Visual acuity allowing normal perception of stimuli or corrected to normal vision Exclusion Criteria: * Every participant having a vascular stent implanted less than 6 weeks before study * Every participant having a biomedical material implanted that is considered "unsafe" in the list: http://www.mrisafety.com/TheList\_search.asp * Every acquisition procedure not respecting required conditions by the "conditional" usage in a participant having a biomedical material implanted that is considered "conditional" in the list: http://www.mrisafety.com/TheList\_search.asp * Every subject having a biomedical material such as a cardiac, neuronal or sensorial stimulator (cochlear implant because of demagnetization, electrode heating or artefact risk) or a ventricular drain without trained medical or paramedical support during MRI for these participants * Ferromagnetic object inside the eye or the skull, close to nervous structures (displacement and complications risk such as eye or brain damage) * Claustrophobia * Psychiatric (e.g., bipolar disorder) or neurological pathology (e.g., epilepsy, Parkinson's Disease) other than Alzheimer's Disease * Non cooperating participant * Severe and uncontrolled affection: cardiac, respiratory, haematological, renal, hepatic, cancerous * Participation to other research protocols with exclusion period or MRI during the past weel * Drug therapy likely to modulate brain activity : neuroleptics, lithium, etc... * Alcohol ingestion before study * Participants concerned by articles L1125-5 to L1121-8 of CSP (Code de la Santé Publique) (pregnant or nursing women, underage or protected adult, person under administrative or judicial oversight * Participant receiving more than 4500 euros for his participation to other studies involving human person during the past 12 months before this study * Participant unable to be contacted in case of emergency * Inability to understand study instructions or give an informed consent