“…Then, they were found in various other areas of the brain (Figure 9.1), including the olfactory bulb, preoptic/septal regions, hypothalamus, limbic system including the amygdala (Arai, 1981;Segovia and Guillamon, 1993) with different sizes and synapdc organization between the genders. Aromatase activity and androgen receptors in various brain regions during adulthood are also sexually differentiated by neonatal steroid treatment, with higher activity in the male than the female (Roselli and Klosterman, 1998). Recent studies indicate that maternal progesterone plays an important role in brain sexual differentiation, because a numerous number of progesterone receptors are found in the neonatal male rat but not in the female (Wagner et al, 1998).…”