Alzheimer Disease/complications; Ciliary Neurotrophic Factor/biosynthesis; Ciliary Neurotrophic Factor/therapeutic use; Memory Disorders/etiology; Memory Disorders/therapy; Synapses/drug effects; Alzheimer Disease/genetics; Amyloid beta-Peptides/administration & dosage; Amyloid beta-Peptides/metabolism; Amyloid beta-Peptides/pharmacology; Amyloid beta-Protein Precursor/genetics; Animals; Apoptosis/genetics; Brain/pathology; Cell Count/methods; Cell- and Tissue-Based Therapy/methods; Cells, Cultured; Ciliary Neurotrophic Factor/administration & dosage; Disease Models, Animal; Enzyme Inhibitors/pharmacology; Enzyme-Linked Immunosorbent Assay/methods; Gene Expression Regulation/drug effects; Gene Expression Regulation/genetics; Green Fluorescent Proteins/genetics; Humans; Male; Maze Learning/physiology; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation/genetics; Neurons/drug effects; Neurons/metabolism; Peptide Fragments/administration & dosage; Peptide Fragments/pharmacology; Signal Transduction/drug effects; Synapses/metabolism; Synaptosomes/metabolism; Synaptosomes/pathology; Synaptosomes/ultrastructure; Time Factors; Transfection/methods