Methods are disclosed for delivering a heterologous gene to a cell body of a neuron by contacting a muscle tissue innervated by the neuron with a viral vector comprising a heterologous gene, wherein the viral vector enters said neuron and is retrogradely moved to the cell body. Additionally, methods for expressing secreted proteins from a nerve cell body as well as methods for treating neurodegenerative disorders such as amyotrophic lateral sclerosis are described.