Interest in the effects of early adversity on children's development reflects contemporary emphases on early experience in the behavioral sciences and plasticity in the neurosciences. Over the past decade, powerful new tools and approaches for understanding the neural circuitry involved in emotion have become increasingly available. Yet, research in developmental psychopathology has not reaped the full benefits of affective neuroscience approaches and methods. Integration of affective neuroscience approaches can excavate developmental mechanisms, thereby advancing knowledge about the etiology, prevention, and treatment of mental health problems in children. Here, we consider two general principles that can guide understanding of plasticity in the neural circuitry of emotion systems and the development of psychopathology.