Normal aging is associated with an increase in word finding problems. Competing explanations posit that age impairs access to phonological representations (transmission deficit) or leads to a deterioration of semantic representations (under-activation). Because these accounts are difficult to disentangle in a highly interactive language system, we employed a neuro-biologically grounded spiking network model which was lesioned to reflect transmission deficits or under-activation. Results of three simulated picture naming paradigms were in line with the transmission deficit account that normal aging impairs access to representations during word production. These initial findings suggest that this is a promising approach for understanding age-related changes to language ability in an interactive system.