Sex differences in dendritic structure in the preoptic area of the juvenile macaque monkey brain.

Quantitative analysis of Golgi-stained neurons in the preoptic area of the brain of prepuberal Macaca fascicularis monkeys indicated structural differences between males and females. Neurons of males had more dendritic bifurcations and a higher frequency of spines. The bifurcation difference appeared in all cell types and was concentrated in the ventrolateral preoptic area. The spine difference was greatest in the central region of the preoptic area. No differences in gross measurements of this brain region were found. These results suggest that sexual dimorphism in the function of the monkey preoptic area may be based on differences in neuronal structure.