4.2. Amygdala
Several studies have reported morphological and functional sex differences in the amygdala. The effect of sex differences in the human amygdala affect the formation of emotional memory, sexual behavior, and psychological disorders (Hamann S, 2005). Namely, altered amygdalar function in autism is four times more frequent in males compared to females and has been linked to the greater prevalence of depression in women. (Hamann S, 2005). In neonates with maternal psychological distress, the volume of the left amygdala was smaller in male than that in females (Lehtola SJ et al., 2020). This could be explained by sex-different adaptation to cortisol levels, which leads to postnatal amygdalar enlargement in females (Buss C et al., 2020).
4.3. Hypothalamus
The hypothalamus is another sexually dimorphic brain structure that have been studied in neonates. Between 36 and 43 weeks of gestational age, males exhibited a larger left thalamic volume than females, but this difference disappeared after controlling for ICV (Giu A et al., 2013). The sexually dimorphic nucleus of the preoptic area of the hypothalamus is more than twice as large in young adult males compared to females and contains about twice as many cells in men (Swaab DF and Fliers E; 1985), . However, the distinction in sex-related characteristics becomes noticeable only between the ages of 4 years and puberty. At a younger age, it appears that the total number of cells and the rate of growth are comparable between the two sexes (Swaab DF and Hofman MA, 1988).