Larger Amygdala but no Change in Hippocampal Volume in 10-Year-Old Children Exposed to Maternal Depressive Symptomatology since Birth
Référence bibliographique 
Lupien, Sonia J., Parent, Sophie, Evans, Alan C., Tremblay, Richard E., Zelazo, Philip David, Corbo, Vincent, Pruessner, Jens C. et Séguin, Jean R. 2011. «Larger Amygdala but no Change in Hippocampal Volume in 10-Year-Old Children Exposed to Maternal Depressive Symptomatology since Birth ». Proceedings of the National Academy of Sciences, vol. 108, no 34, p. 1-6.
Intentions : The authors want «[t]o determine if poor maternal care associated with maternal depressive symptomatology has a similar pattern of association to the volumes of the hippocampus and amygdala in children [...].» (p. 1)
Échantillon/Matériau : The sample of this study is composed of 38 children born in 1996 selected from a ongoing Quebec Longitudinal Study of Child Development. «Two-way repeated-measure ANOVAs were performed on amygdala and hippocampal volumes using MDS group and sex as the between-subject factors and hemisphere (left versus right volume) as the within-subject factor. [And] a two-way repeated-measure ANOVA was performed on salivary glucocorticoid levels using MDS group and sex as the between-subject factors, time (arrival versus prescan versus postscan) as the within-subject factor, and time of sampling as a covariate.» (p. 2)
Type de traitement des données : Anlayse statistique
«Maternal separation and poor maternal care in animals have been shown to have important effects on the developing hippocampus and amygdala. In humans, children exposed to abuse/maltreatment or orphanage rearing do not present changes in hippocampal volumes. However, children reared in orphanages present enlarged amygdala volumes, suggesting that the amygdala may be particularly sensitive to severely disturbed (i.e., discontinous, neglectful) care in infancy. Maternal depressive symptomatology has been associated with reductions in overall sensitivity to the infant, and with an increased rate of withdrawn, disengaged behaviors. [...] Results revealed no group difference in hippocampal volumes, but larger left and right amygdala volumes and increased levels of glucocorticoids in the children of mothers presenting depressive symptomatology since birth. Moreover, a significant positive correlation was observed between mothers’ mean depressive scores and amygdale volumes in their children. The results of this study suggest that amygdala volume in human children may represent an early marker of biological sensitivity to quality of maternal care.» (p. 1)
Perceived Early-Life Maternal Care and the Cortisol Response to Repeated Psychosocial Stress
Référence bibliographique 
Engert, Veronika, Efanov, Simona I., Dedovic, Katarina, Duchesne, Annie, Dagher, Alain et Pruessner, Jens C. 2010. «Perceived Early-Life Maternal Care and the Cortisol Response to Repeated Psychosocial Stress ». Journal of Psychiatry and Neuroscience, vol. 35, no 6, p. 370-377.
Intentions : «In the current study, we investigated the influence of early life maternal care on single and repeated TSST [Trier Social Stress Test] exposure.» (p. 971)
Questions/Hypothèses : «[W]e expected the low maternal care group to show a continuously high cortisol response upon repeated stress exposure.» (p. 371)
Échantillon/Matériau : L’échantillon se compose de 63 jeunes adultes âgés entre 18 et 30 ans recrutés à partir d’un babillard électronique du site internet de l’Université McGill.
Instruments : Questionnaires
Type de traitement des données : Analyse statistique
«In the past decade, a body of animal and human research has revealed a profound influence of early-life experiences, ranging from variations in parenting behaviour to severe adversity, on hypothalamic–pituitary–adrenal axis regulation in adulthood. In our own previous studies, we have shown how variations in early-life parental care influence the development of the hippocampus and modify the cortisol awakening response. [...] Controlling for the effect of sex, we found an inverted u-shaped relation between increasing levels of maternal care and cortisol stress responsivity. Specifically, overall and stress-induced cortisol levels went from below normal in the low maternal care, to normal in the medium care, back to below normal in the high maternal care groups. We found no group differences with respect to heart rate and subjective psychological stress measures. Whereas low and high maternal care groups exhibited similarly low endocrine stress responses, their psychological profiles were opposed with increased levels of depression and anxiety and decreased self-esteem in the low care group. [...] We discuss the potential significance of this dissociation between endocrine and psychological parameters with respect to stress vulnerability and resistance for each maternal care group.» (p. 370) Note : Le stress intra et extra familial pendant l’enfance et l’adolescence est analysé dans l’article.