Maternal separation and poor maternal care have been shown to have important effects on the developing hippocampus and amygdala in animal studies. However, human children in abusive environments do not necessarily show changes in hippocampal volumes. Interestingly, children reared in orphanages have been reported to have enlarged amygdala volumes, suggesting that the amygdala may be particularly sensitive to a disturbed childhood environment. In this study, Lupien and coworkers measured hippocampal and amygdala volumes as well as stress hormone (glucocorticoid) levels in children exposed to maternal depressive symptomatology since birth. Results revealed no group difference in hippocampal volumes, but larger left and right amygdala volumes and increased levels of glucocorticoids in the children of mothers presenting depressive symptomatology since birth. The authors suggest that amygdala volume in human children may represent an early marker of biological sensitivity to quality of maternal care.
Lupien SJ et al. Larger amygdala but no change in hippocampal volume in 10-year-old children exposed to maternal depressive symptomatology since birth.
Proc. Natl. Acad. Sci. USA [Epub ahead of print, August 15, 2011]; doi:10.1073/pnas.1105371108.
http://www.pnas.org/content/early/2011/08/08/1105371108.abstract