Gray matter maturation is differentially influenced by early-life and pubertal stressful experiences : a prospective longitudinal study

The early developing brain has been shown to be sensitive to stress, but less is known about the impact of early-life stress on neural maturation during adolescence. Based on animal and human literature we hypothesized that stress may interfere with known patterns of neural development during adolescence, namely subcortical growth and prefrontal pruning. In a prospective longitudinal study, 37 adolescents were followed since 15 months of age. We tested the relative impact of adverse events experienced early in life (until age 5) and recently (between age 14 and 17), involving personal events and social environment on brainchanges occurring between age 14 and 17. Personal events were indexed with the Life Events Scale. Social environment was indexed with peer social preference. We focus on changes in gray matter volume (GMV) in the amygdala-hippocampal complex and in prefrontal cortex. Preliminary results show that GMV changes in those regions were differentially affected by early and recent experiences. Early adverse life-events were associated with a relative reduction of the amygdala-hippocampal region and insula. Recent exposure to an adverse social environment was associated with changes in the posterior hippocampus and prefrontal cortex.These findings suggest that brain maturation between age 14 and 17 is particularly sensitive to adverse personal events early in life, and to adverse social events during adolescence. These findings open the way to understand how personal and social adverse events lead to alterations in social and emotional behavior inadults.