Early acoustic experience affects the structure of neurons in the brainstem of young chickens. In the binaurally innervated cells of the nucleus laminaris the symmetry of the dorsal and ventral dendritic trees normally increases during the embryonic and early postnatal period. Unilateral ear plugs disrupt that development. This study shows that balanced stimulation plays an important role in the development of symmetrical neuronal structures in the central auditory pathway.