A developmental perspective on the regulation of arousal states.

Arousal regulation is an organizing construct for describing the relations between stimulation, stress, and cortical activity and performance. It describes a dynamic process of cortical activation and behavior in response to varying levels of stimulation. Contemporary neurobiological perspectives provide evidence that the concept of arousal regulation involves complex interactions among different neurochemical systems in the pontine and midbrain reticular formation. These interactive arousal systems serve as multilevel gates that both protect cortex from excessive stimulation and facilitate coordination between attentional, executive, and sensory cortical systems. The coordination between these systems emerges over the course of development with increasing balance of inhibitory and excitatory processes. The threshold for switching between more executive and more automatic modes of functioning also changes with development and may be particularly sensitive to early stressful and/or traumatic experiences.