Developmental and neurobehavioral transitions in survival circuits

Although animals of all ages experience threats, the neurobehavioral response to threat shows fundamental changes across development in altricial species, including humans and rodents. Although the mature animal has an arsenal of defensive strategies to engage, including attack, escape, hide or freeze, the motorically immature infant exhibits age-appropriate responses to threats that involve approach to the caregiver for protection. The neurobiology supporting this difference relies on both the immature state of the infant brain and neural networks specifically adapted to its unique environmental niche. Using examples from innate threats, we review the development of threat survival circuit neurobiology to illustrate developmental transitions and the important role of the caregiver in controlling the infant's neurobehavioral response to threat.