Early life adversity shapes neural and behavioural responses to oxytocin during altruistic decision-making.

What makes some people willing to help strangers at a personal cost, while others are more hesitant or selective? Early life adversity - such as neglect or abuse - may shape how we respond to strangers in need later in life, yet the underlying neural mechanisms remain unclear. In this study we tested whether the neuropeptide oxytocin, a key modulator for a rich repertoire of social behaviours, influences altruistic decisions in adults with different childhood experiences. Using functional magnetic resonance imaging (fMRI) and a validated altruistic donation task, the study showed that oxytocin increased donations among individuals with greater childhood adversity, while reducing them in those with lower adversity. These behavioural effects were mirrored by changes in functional connectivity between the medial prefrontal cortex and middle cingulate cortex - core circuits involved in social evaluation and empathy. Our findings suggest that early life experiences sensitize neural pathways for social processing, and that oxytocin dynamically modulates these circuits to influence altruistic behaviour in adulthood.