Mothers’ unresolved trauma blunts amygdala response to infant distress

Abstract

While the neurobiology of post-traumatic stress disorder has been extensively researched, much less attention has been paid to the neural mechanisms underlying more covert but pervasive types of trauma (e.g., those involving disrupted relationships and insecure attachment). Here, we report on a neurobiological study documenting that mothers’ attachment-related trauma, when unresolved, undermines her optimal brain response to her infant’s distress. We examined the amygdala blood oxygenation level-dependent response in 42 first-time mothers as they underwent functional magnetic resonance imaging scanning, viewing happy- and sad-face images of their own infant, along with those of a matched unknown infant. Whereas mothers with no trauma demonstrated greater amygdala responses to the sad faces of their own infant as compared to their happy faces, mothers who were classified as having unresolved trauma in the Adult Attachment Interview (Dynamic Maturational Model) displayed blunted amygdala responses when cued by their own infants’ sadness as compared to happiness. Unknown infant faces did not elicit differential amygdala responses between the mother groups. The blunting of the amygdala response in traumatized mothers is discussed as a neural indication of mothers’ possible disengagement from infant distress, which may be part of a process linking maternal unresolved trauma and disrupted maternal caregiving.

Keywords:

• Unresolved trauma
• Amygdala
• Attachment
• Mother–infant relationship

We would like to thank Udita Iyengar and Sheila Martinez for assistance with data management and analysis, and the technical staff of the Center for Advanced Magnetic Resonance Imaging (CAMRI) at Baylor College of Medicine for assistance with conducting the experiments.

This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development [K23HD43097, R01HD065819]; General Clinical Research Center [MO1RR00188]; the Baylor Child Health Research Center: Pediatrics Mentored Research Program [K12HD41648]; and the National Institute on Drug Abuse [R01DA026437]. The content is solely the responsibility of the authors and does not necessarily represent the official views of these institutes or the National Institutes of Health.

The authors declare no competing financial interests.