Decreased amygdala volume in adults after premature birth

Benita Schmitz-Koep,Aurore Menegaux,Peter Bartmann,Claus Zimmer,Henning Boecker,Josef G Bäuml,Dieter Wolke,Sebastian C Schneider,Christian Sorg,Marcel Daamen,Rachel Nuttall,Juliana Zimmermann,Dennis M Hedderich

doi:10.1038/s41598-021-84906-2

Benita Schmitz-Koep, Aurore Menegaux + Show 11 more

Open Access

https://doi.org/10.1038/s41598-021-84906-2

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Abstract

Premature-born infants have impaired amygdala structure, presumably due to increased stress levels of premature birth mediated by the amygdala. However, accounting for lifelong plasticity of amygdala, it is unclear whether such structural changes persist into adulthood. To address this problem, we stated the following questions: first, are whole amygdala volumes reduced in premature-born adults? And second, as adult anxiety traits are often increased after prematurity and linked with amygdala structure, are alterations in amygdala associated with adults’ anxiety traits after premature birth? We addressed these questions by automated amygdala segmentation of MRI volumes in 101 very premature-born adults (< 32 weeks of gestation and/or birth weight below 1500 g) and 108 full-term controls at 26 years of age of a prospectively and longitudinally collected cohort. We found significantly lower whole amygdala volumes in premature-born adults. While premature-born adults had significantly higher T score for avoidant personality reflecting increased social anxiety trait, this trait was not correlated with amygdala volume alterations. Results demonstrate reduced amygdala volumes in premature born adults. Data suggest lasting effects of prematurity on amygdala structure.

Highlights

Premature-born infants have impaired amygdala structure, presumably due to increased stress levels of premature birth mediated by the amygdala
Total intracranial volume (TIV) was significantly smaller in very preterm (VP)/very low birth weight (VLBW) individuals compared to controls (p = 0.001)
We tested whether whole amygdala volumes are altered in VP/VLBW adults compared to FT controls using general linear models

Summary

Introduction

Premature-born infants have impaired amygdala structure, presumably due to increased stress levels of premature birth mediated by the amygdala. Very premature-born adults, i.e. born very preterm (VP) before 32 weeks of GA and/or with very low birth weight (VLBW) below 1500 g, have on average more than 10 points lower full-scale IQ scores compared to full-term (FT) controls, which is mediated by aberrant development of distinct brain structures or processes such as cortical folding, white matter integrity and subcortical grey matter volume[5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]. Amongst multiple brain systems affected in human prematurity, the amygdala might be interesting for two particular reasons: First, the amygdala mediates the brain’s stress responses, with stress being a critical factor of premature birth; and second, the amygdala mediates anxiety and social anxiety behavior, which are both often increased after premature birth We will explore these reasons in more detail in the following paragraphs. Accounting for lifelong plasticity of the amygdala[39,40,41], it remains unclear whether amygdala volumes are lastingly altered into adulthood after premature birth

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