Effects of neonatal undernutrition and binaural ear occlusion on neuronal development of the superior olivary complex of rats

Golgi-Cox-impregnated neurons of the superior olivary complex were investigated in control, binaural ear-occluded control, undernourished, and binaural ear-occluded undernourished Wistar rats of 12, 20, and 30 days of age. In neonatally undernourished and binaural ear-occluded animals, a significant reduction in the number of dendrites and dendritic intersections in the medial trapezoid body neurons was observed. Inconsistent effects upon the dendritic arbor lateral superior olivary cells were also detected. Control and undernourished rats with binaural ear occlusion exhibited a significant increase in the dendritic arbor measurements of lateral superior olivary neurons as compared with the cells of the medial trapezoid body. The cytoarchitectonic imbalance between the modulatory efferent control of these systems and the sensory auditory input to the cochlea may be important for the integration of complex auditory physiological phenomena.