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).