Have you ever wondered whether your parents’ or grandparents’ lived experiences had any impact on your mind and behavior? While we can’t answer this question definitively, a similar question can be addressed by studies in recent years examining the intergenerational transmission of maternal trauma. Their findings suggest that the trauma experienced by mothers can leave a mark on their children in the form of behavioral and neural manifestations.1,2,3 In particular, a recent study released in the April 2021 issue of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging discovered an association between maternal childhood experiences with adversity and the frontoamygdala connectivity in newborns.1 In other words, mothers’ early life traumatic experiences were found to have functional impacts on the formation of their newborns’ fear and anxiety-processing brain areas.

Although this is not the first time the long term and hereditary impacts of adversity have been studied, it is the first study to discover changes in the neural circuitry of newborns that correlate to maternal childhood trauma.1 The study followed 41 Black women from their first trimester of pregnancy through their first 18 months postpartum.1 Maternal childhood adversity was measured through a retrospective survey using the Childhood Trauma Questionnaire-Short Form (CTQ).1 The CTQ gauged the mothers’ childhood experiences with sexual abuse, physical abuse, emotional abuse, physical neglect, and emotional neglect. To prevent confoundment with the effects of the stress the mother experienced during pregnancy, prenatal distress was assessed through stress, anxiety, and depression scales. Infant brain circuitry was examined through resting-state functional magnetic resonance imaging (rsfMRI), which is conducted while the baby was in natural sleep.1 

MRI is a noninvasive imaging technique that uses radio waves and a magnetic field to generate cross-sectional images of the infants’ brains.2 fMRI is a more specialized form of MRI in which the blood circulation of the brain is visualized, to help analyze structure and function.2 In this study, an fMRI is used to allow for the targeted analysis of the emotion-processing centers of the newborns’ brains. 

After controlling for maternal prenatal stress, the study found that a mother’s experiences of childhood emotional neglect correlated with stronger functional coupling (FC, referring to the correlation or coordination of function among structures) between her baby’s amygdala and ventromedial prefrontal cortex (vmPFC), and between the amygdala and dorsal anterior cingulate cortex (dACC) across both hemispheres.1 Specifically, it was found that the more maternal emotional neglect experienced, the stronger the amygdala-dACC FC (Figure 1).1 The changes in frontoamygdala connectivity were observed to correlate specifically with emotional neglect and not with maternal childhood experiences with physical neglect or abuse.1 

To further explore the implications of these findings, we can first examine the main functions of these brain regions involved. The amygdala is the emotion-processing center of the brain, which is also involved in regulating reactions to fear and stress—such as the well-known “fight or flight” response.3 The amygdala is a part of the limbic system, one of the oldest and most important brain systems for processing emotions and for survival in general. The dACC, which is in communication with both the limbic system and the prefrontal cortex, is involved in impulse control, attention regulation, and salience detection (in other words, the ability to prioritize events for learning and survival).3 

The exact implications of stronger functional coupling between the amygdala and prefrontal systems are unclear. According to the researchers, this alteration could either render the infant more at risk for anxiety or more resilient, in case the infant also receives less emotional support from caregivers.4 In either case, stronger functional coupling is likely to result in greater attentiveness to social-emotional information and awareness of threats in the environment, even from birth.3,4 The results of this research confirm that maternal childhood emotional neglect can cause changes in neural circuitry that translate across generations. Future studies that follow the children with altered frontoamygdala connectivity will further illuminate the social and developmental significance of the changes.4 

References

[1] Hendrix, C.L., et al. “Maternal Childhood Adversity Associates With Frontoamygdala Connectivity in Neonates.” Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, vol. 6 (4), 2021, doi: 10.1016/j.bpsc.2020.11.003

[2] Bierer, L.M., et al. “Elevation of 11β-hydroxysteroid dehydrogenase type 2 activity in Holocaust survivor offspring: Evidence for an intergenerational effect of maternal trauma exposure.” Psychoneuroendocrinology, vol. 48, 2014, https://doi.org/10.1016/j.psyneuen.2014.06.001

[3] Moog, N.K., et al. “Intergenerational Effect of Maternal Exposure to Childhood Maltreatment on Newborn Brain Anatomy.” Biological Psychiatry, vol. 83 (2), 2018, https://doi.org/10.1016/j.biopsych.2017.07.009 

[4] “MRI.” Retrieved April 25, 2021, from https://www.mayoclinic.org/tests-procedures/mri/about/pac-20384768#:~:text=Magnetic%20resonance%20imaging%20(MRI)%20is,large%2C%20tube%2Dshaped%20magnets. 

[5] Krause-Utz, A., et al. “Amygdala and dorsal anterior cingulate connectivity during an emotional working memory task in borderline personality disorder patients with interpersonal trauma history.” Frontiers in Human Neuroscience, 2014, doi: 10.3389/fnhum.2014.00848

[6] “Childhood Neglect Leaves Generational Imprint.” Neuroscience News, 19 Jan. 2021. https://neurosciencenews.com/childhood-neglect-generational-17597/