Insertion of the BDNF gene within alentiviral vector into J20 transgenic mice (carrying mutations in the geneencoding the amyloid precursor protein) prevented the death of the cells of theentorhinal cortex and improved cognitive functions [7].It has been shown using another genetic model of AD (P301Lmice carrying the mutant tau protein gene) that stable human BDNF geneexpression restored the BDNF level, thus preventing neuronal and synapticdegeneration in the hippocampus, as well as cognitive disorders[8]. This evidence concerns the gene BDNF and Cognitive impairment.