My laboratory studied the functions of neurotrophic factors in development and their relevance to neurodegenerative disease using a blend of transgenic mouse technology and anatomical, cell biological, and molecular techniques. We have used powerful conditional “gene knockout” techniques involving the cre/lox recombinase system to create mice that lack neurotrophic factors only in a specific tissue. This allowed us to dissect functions in a specific tissue and/or at a specific developmental stage. We focused primarily on the neurotrophin BDNF, and have shown that it is important in stabilizing the dendritic structure of neurons. Interestingly, this may relate to a requirement for BDNF in the formation or stabilization of many synapses. We also identified compelling parallels between BDNF deprivation and Parkinson’s and Huntington’s diseases and are using our BDNF mutant mice to identify useful compounds and targets in treating these and other neural disorders.