Exposure to unpredictable childhood environments is associated with amygdala activation during early extinction in adulthood.

Early adversity can alter the maturation and function of neural regions that support affective functioning, including threat and safety learning. A growing body of cross-species research has specifically focused on the role of unpredictability in childhood environments in shaping affective functioning; however, the links between childhood unpredictability and neural function related to extinction learning in adulthood remain unclear. In this study, we probed the association between childhood unpredictability, extinction learning, and neural activation in four regions implicated in extinction learning in healthy young adults (N = 45; aged 18-30 years). Results revealed that adults exposed to more unpredictable childhood environments showed greater basolateral amygdala activity to the former (i.e., extinguished) threat cue during early, but not late, extinction, including when controlling for current anxiety and childhood trauma exposure. An exploratory analysis showed that exposure to unpredictable caregiving, but not distal unpredictability (e.g., unpredictability of the physical home or community), specifically drove findings in the amygdala. Childhood unpredictability was not associated with activity in the other regions of interest or with skin conductance response during extinction. These findings add to a growing literature on longstanding impacts of unpredictable caregiving environments, with implications for promoting healthy neurodevelopment and targeted clinical interventions.