Abstract
Animal studies show that exposure to parental neglect alters stress regulation and can lead to neural hyposensitivity or hypersensitivity in response to cortisol, most pronounced in the hippocampus. Cortisol, the end product of the hypothalamic-pituitary-adrenal (HPA) axis, has also been related to parenting more directly, for example, in both sexes, cortisol levels increase when listening to infants crying, possibly to activate and facilitate effective care behavior. Severe trauma is known to negatively affect the HPA-axis in humans; however, it is unknown whether normal variation in parental care in the healthy population can alter sensitivity of the hippocampus to cortisol. Here, we investigate whether variation in experienced neglect changes neural sensitivity to cortisol when humans listen to infant crying, which is an unequivocal signal relevant for care behavior. In a placebo-controlled, within-subject neuroimaging study, we administered 40 mg cortisol to 21 healthy young males without children and used a validated task for measuring neural responses to infant crying. The Dutch version of the Childhood Trauma Questionnaire was used to index participants' early exposure to abuse and neglect. The data show that cortisol markedly increased hippocampal activation toward crying infants, and this effect varied significantly with parental neglect, even in our nonclinical subject sample. Without exposure to severe trauma or neglect, reduced self-experienced quality of parental care in the normal range already substantially increased hippocampal responsivity to cortisol. Altered hippocampal sensitivity to cortisol might be a cross-species marker for the risk of developing later life psychopathology.