Prediction of Cognitive Decline by Neuroimaging Techniques and the Application in Diagnosis and Treatment of Preclinical AD

1\. NC Inclusion Criteria: 1. Older than 60, right handedness, Han nationality; 2. Have no cognitive decline complains, with neither worry nor concern about their cognition; 3. Scores of standardized neuropsychological tests scale adjusted for age, sex and education are in normal range; 4. Physical examination is negative; 5. Review medical history and family history is negative, accessory examination don't show disease could cause cognitive decline; 6. Could cooperate collection of multi-modal magnetic resonance imaging, once a year, for continueously five years. 2\. SCD Inclusion Criteria: 1. Presence of self-perceived continuous cognitive decline compared to previous normal status and unrelated to an acute event; 2. Failure to meet the following criteria for MCI. 3.SCD-plus Inclusion Criteria: 1. Presence of self-perceived continuous cognitive decline compared to previous normal status and unrelated to an acute event; 2. Concerns (worries) associated with memory complaint; 3. Failure to meet the following criteria for MCI. 3\. MCI Inclusion Criteria: 1. Clinical Dementia Rating (CDR) score of 0.5 as well as failure to meet the criteria for dementia 2. Having impaired scores (defined as \>1 SD below the age-corrected normative mean) on both measures within at least one cognitive domain (i.e., memory, language, or speed/executive function); 3. Having impaired scores in each of the three cognitive domains sampled; 4. the Functional Activities Questionnaire (FAQ) ≥9. 4\. AD Inclusion Criteria The diagnosis of AD syndrome is based on the diagnostic guidelines for dementia due to AD delivered by the National Institute on Aging-Alzheimer's Association workgroups (NIA-AA)with a total CDR score of 1. Exclusion Criteria: 1. Claustrophobia, with metals in the body that cannot be examined by MRI, including metal dentures or other contraindications for examination; 2. Left handedness or ambidextrality.