Executive functions are a set of interdependent, progressively acquired, higher-order cognitive skills that emerge in tandem with the expansion and integration of cerebellar, subcortical, corticocortical, and prefrontal neural networks across early childhood, through adolescence, and into early adulthood. Because the development of neural systems that support EF is so protracted, it is vulnerable across time to alterations in its unfolding trajectory, resulting in multiple possible routes to EdF. This chapter provides a summary of the underlying neuroanatomical and neurochemical substrates of EF development that support the behavioral and cognitive capacities discussed in Chapter 2. Although a primary emphasis of this chapter is typical EF development, discussion of abnormalities in and insults to the developing circuits that support EF are also considered.
In contrast to models that describe the neural underpinnings of EF in adults, which emphasize modularity and take a reductionist approach to characterizing the “how and where” of executive capabilities, given their focus on the frontal lobes, models of early brain development and its role in the establishment of EF are much less “tidy” and “bounded”. Instead, the boundaries of what constitutes EF in childhood and the description of specific structures supporting its elicitation are less distinct and are more broadly situated anatomically. As a result, the classical emphasis on frontal cortical networks that characterizes adult neuropsychology is inadequate when thinking about EF developmentally. Instead, when considering the developmental neurobiology of EF, it is important to think about how the whole brain organizes and establishes its connections over time and across neural space, in order to best understand and make sense of the increasingly automatic and controlled responses that emerge neuropsychologically.