Critical fear: Developmental trajectories of traumatic life experiences during specific sensitive periods

Life experiences wield particular influence over brain development during restricted time windows (i.e., critical periods), when the brain is more responsive to environmental stimuli. Positive experiences during critical periods lead to healthy brain wiring and development of proper behavioral skills. Conversely, diverse traumatic life experiences (e.g., physical/sexual abuse, prolonged hospitalization, warfare) can damage the brain structure and connectivity, increasing the risk for neuropsychiatric disorders (e.g. depression, anxiety, post-traumatic stress disorder, attention-deficit/hyperactivity disorders and personality disorders). In this context, although the nature of traumatic life experiences can vary largely, the consequent neuropsychiatric conditions are in a restricted number. Moreover, no direct links exist between specific traumatic life experiences and the insurgence of certain neuropsychiatric traits, suggesting that a particular traumatic event can trigger different psychiatric consequences. In C57BL/6J mice, we here investigated whether the timing of the life-threatening experience can play a role in the mismatch between the type of trauma and the specific neuropsychiatric outcome. Our results revealed the existence of critical periods for adult psychiatric disorders, which differentially modulate the adult behavioral outcome and induce area-specific molecular patterns in the brain of experimental mice.