This technology relates to a mouse model that improves an existing method of disrupting the production of the BDNF protein in specific parts of the brain. A current avenue of research seeks to examine how gene expression may effect long-lasting changes in the nervous system. Previous work has resulted in a mouse line in which the production of BDNF was disrupted. However, these mice had an inadvertent genetic component left in: a neomycin cassette. This unintentional addition led to significant deleterious effects. Researchers at NCI and NIMH have updated these mouse models by removing the neomycin cassette, alleviating the undesired side effects.