While the etiology of motor neuron disease as yet is unknown, the neuron bears significant injury in the disease. Using a neurotropic virus as a probe, we will examine clonal neuroblastoma cells that have been acutely or persistently infected, to detect alterations in cellular and neural-specific functions. As the neuron is a post mitotic cell, viral-host interactions will be explored in the differentiated cell and compared to an infection in actively dividing cultures. Cell cycle parameters will be established in the neural cells, and differentiated function, including neurite outgrowth and production of neurotransmitters will be induced by established chemical or physical means. Acute or persistent viral infection will be monitored by both morphologic and biochemical methods. Cell clones expressing selected neural functions such as cholinergic etc., will be screened for differential effects on viral replication which might indicate any special vulnerability of neurons of a specific functional type. Such an approach may give information on neurologic diseases involving selected neuronal systems.