title: Altered Amygdala Development and Fear Processing in Prematurely Born Infants.
abstract: BACKGROUND
  Prematurely born children have a high risk of developmental and behavioral disabilities. Cerebral abnormalities at term age have been clearly linked with later behavior alterations, but existing studies did not focus on the amygdala. Moreover, studies of early amygdala development after premature birth in humans are scarce.
  
  
  OBJECTIVE
  To compare amygdala volumes in very preterm infants at term equivalent age (TEA) and term born infants, and to relate premature infants' amygdala volumes with their performance on the Laboratory Temperament Assessment Battery (Lab-TAB) fear episode at 12 months.
  
  
  METHODS
  Eighty one infants born between 2008 and 2014 at the University Hospitals of Geneva and Lausanne, taking part in longitudinal and functional imaging studies, who had undergone a magnetic resonance imaging (MRI) scan at TEA enabling manual amygdala delineation.
  
  
  RESULTS
  Amygdala volumes assessed by manual segmentation of MRI scans; volumes of cortical and subcortical gray matter, white matter and cerebrospinal fluid (CSF) automatically segmented in 66 infants; scores for the Lab-TAB fear episode for 42 premature infants at 12 months.
  
  
  RESULTS
  Amygdala volumes were smaller in preterm infants at TEA than term infants (mean difference 138.03 mm(3), p < 0.001), and overall right amygdala volumes were larger than left amygdala volumes (mean difference 36.88 mm(3), p < 0.001). White matter volumes were significantly smaller (p < 0.001) and CSF volumes significantly larger (p < 0.001) in preterm than in term born infants, while cortical and subcortical gray matter volumes were not significantly different between groups. Amygdala volumes showed significant correlation with the intensity of the escape response to a fearsome toy (rs = 0.38, p = 0.013), and were larger in infants showing an escape response compared to the infants showing no escape response (mean difference 120.97 mm(3), p = 0.005). Amygdala volumes were not significantly correlated with the intensity of facial fear, distress vocalizations, bodily fear and positive motor activity in the fear episode.
  
  
  CONCLUSIONS
  Our results indicate that premature birth is associated with a reduction in amygdala volumes and white matter volumes at TEA, suggesting that altered amygdala development might be linked to alterations in white matter connectivity reported in premature infants. Moreover, our data suggests that such alterations might affect infants' fear-processing capabilities.
authors.affiliation: Division of Development and Growth, Department of Pediatrics, Hospital of Geneva Geneva, Switzerland.
authors.forename: Anca Liliana
authors.initials: AL
authors.lastname: Cismaru
authors.affiliation: Division of Development and Growth, Department of Pediatrics, Hospital of Geneva Geneva, Switzerland.
authors.forename: Laura
authors.initials: L
authors.lastname: Gui
authors.affiliation: Division of Development and Growth, Department of Pediatrics, Hospital of Geneva Geneva, Switzerland.
authors.forename: Lana
authors.initials: L
authors.lastname: Vasung
authors.affiliation: Child Clinical Neuropsychology Unit, University of Geneva Geneva, Switzerland.
authors.forename: Fleur
authors.initials: F
authors.lastname: Lejeune
authors.affiliation: Child Clinical Neuropsychology Unit, University of Geneva Geneva, Switzerland.
authors.forename: Koviljka
authors.initials: K
authors.lastname: Barisnikov
authors.affiliation: Division of Neonatology, University Hospital of Lausanne Lausanne, Switzerland.
authors.forename: Anita
authors.initials: A
authors.lastname: Truttmann
authors.affiliation: Division of Development and Growth, Department of Pediatrics, Hospital of Geneva Geneva, Switzerland.
authors.forename: Cristina
authors.initials: C
authors.lastname: Borradori Tolsa
authors.affiliation: Division of Development and Growth, Department of Pediatrics, Hospital of Geneva Geneva, Switzerland.
authors.forename: Petra S
authors.initials: PS
authors.lastname: Hüppi
keywords: amygdala; amygdala development; fear; lab-TAB; premature birth