Differential effects of early life stress on hippocampus and amygdala volume as a function of emotional abilities

Abstract

Early life stress (ELS) is known to have considerable influence on brain development and affective functioning. Previous studies in clinical populations have shown that hippocampus and amygdala, two central structures of limbic emotion processing circuits, are predominantly affected by early stress exposure. Given the inconsistent findings on ELS-related effects in healthy populations and the associations of ELS and affective functioning, the question arises which additional emotion-relevant variables need to be considered to better understand the effects of ELS. We, therefore, investigated the volume of hippocampus and amygdala in 25 high alexithymic (h-ALEX) and 25 low alexithymic (l-ALEX) individuals, which were matched with regard to ELS, but significantly differed in their degree of emotional functioning. Volumetric analyses were performed using FSL-FIRST, a method to automatically segment subcortical structures on T1-weighted magnetic resonance images. Alexithymia was assessed using the Toronto Alexithymia Scale and Bermond-Vorst Alexithymia Questionnaire. ELS was assessed by Childhood Trauma Questionnaire (CTQ) and Early Trauma Inventory. Our data showed that ELS was negatively associated with right hippocampus volume in h-ALEX individuals, while there was no such association in the l-ALEX group. Furthermore, ELS was positively associated with left amygdala volume in l-ALEX individuals, but not in individuals with high levels of alexithymia. The present study emphasizes a substantial relationship between intrapersonal factors, such as alexithymia and neural alterations related to the experience of ELS. Longitudinal study designs are necessary to pursue the question of how emotional abilities interact with individual adaptations to early stress exposure on the neural level.

Developmental Trajectories of Early Life Stress and Trauma: A Narrative Review on Neurobiological Aspects Beyond Stress System Dysregulation

“…However, hippocampal volume seems to be unaffected in children but not in adults with maltreatment-related PTSD, suggesting an initially volumetrically normal hippocampus with subsequent abnormal disrupted development (443). With respect to amygdala, the results from human studies regarding the volumetric effect of ELS/CT are inconclusive, with some studies reporting reduced volume (416,428,430,444), some differential effects according to specific type of ELS/CT (432,445), and some even greater amygdala volume (in non-human primates) (446). However, findings are conclusive concerning amygdala responsiveness, as ELS/CT has been repeatedly associated with facial threat-or negative-emotion-related amygdala hyper-responsiveness (416,417,447,448).…”

Utility of the cumulative stress and mismatch hypotheses in understanding the neurobiological impacts of childhood abuse and recent stress in youth with emerging mental disorder

“…Our secondary aim was to extend research on the interaction of childhood and recent stress to individuals in the early stages of mental disorder. For example, childhood maltreatment has been linked to both increased and decreased amygdala volumes in adults [Aas et al, 2012, Cisler et al, 2013, Dean et al, 2014, Frodl et al, 2010, Pechtel et al, 2013, Aust et al, 2014, Hoy et al, 2012, Veer et al, 2015. The advantages of using this trans diagnostic approach in research, in contrast to categorical diagnostic grouping, are discussed at length elsewhere [Casey et al, 2013, Cuthbert, 2014, Cuthbert and Insel, 2013.…”

“…Thirdly, we wished to ascertain whether variability in childhood trauma neuroimaging research stems from differences in recent stress. For example, childhood maltreatment has been linked to both increased and decreased amygdala volumes in adults [Aas et al, 2012, Cisler et al, 2013, Dean et al, 2014, Frodl et al, 2010, Pechtel et al, 2013, Aust et al, 2014, Hoy et al, 2012, Veer et al, 2015. To do so, we designed a study in line with the proposal of Nederhof and Schmidt [2012].…”

Brain structural correlates of alexithymia in patients with major depressive disorder

“…7 In contrast, studies investigating healthy individuals with lower alexithymia scores have found no association or a positive association between alexithymia and grey matter volume. [30][31][32][33] Our aim was to find brain structural correlates of alexithymia in lifetime MDD and brain structural correlates that were differentially associated with alexithymia in healthy controls and patients with MDD. According to the literature, 30,32 people with low alexithymia scores exhibit a positive association between alexithymia and grey matter volume.…”

“…[30][31][32][33] Our aim was to find brain structural correlates of alexithymia in lifetime MDD and brain structural correlates that were differentially associated with alexithymia in healthy controls and patients with MDD. According to the literature, 30,32 people with low alexithymia scores exhibit a positive association between alexithymia and grey matter volume. Thus, we hypothesized a positive association between alexithymia and grey matter volume in FFG and ACC in the healthy controls.…”