A new study links a stress hormone in pregnant mothers to larger amygdalas in children, meaning potential headaches when it comes to emotional development.
In previous research, we've learned that the size of the amygdala -- the part of the brain responsible for handling emotional response and threat perception -- can have an impact on our political outlook and the number of friends in our social networks. Now, a new study finds that maternal stress may be linked to amygdala volume in children, opening up new questions about how many of our social skills are shaped before we're even born.
In a paper published in the Proceedings of the National Academy of Sciences last month, researchers reported that mothers who experienced greater levels of stress during pregnancy tended to produce girls with larger amygdalas. After seven years, these offspring displayed more symptoms of affective disorders.
The scientists had mothers in the study undergo a saliva swab at 15 weeks of gestation to measure for stress hormones. Mothers who had more cortisol in their blood gave birth to girls whose right amygdalas were slightly larger, though the pattern didn't hold for boys. A one-standard deviation increase in maternal cortisol meant, on average, a 6.4 percent increase in amygdala size.