Neural substrates of executive function development in children under three: a mini-review of recent advances

Executive functions (EF) are higher-order cognitive functions, including inhibitory control, working memory, and cognitive flexibility. In 2019, Fiske and Holmboe published a review on the neural substrates of early EF development which mapped what was then known in this field. Much research has been conducted since then, partially spurred by the wider availability of infant-friendly neuroimaging techniques. This has enabled the study of larger and younger cohorts and finer-grained mapping of cortical networks during the first 3 years of life. Here, we provide an updated review of recent research on the neural substrates of early EF development, covering inhibitory control, working memory, and cognitive flexibility. The frontal and parietal cortices emerge as shared neural substrates, although the specific regions recruited and the rates of their specialization vary across EF components and with age. Contextualized within broader evidence on structural prefrontal cortex maturation and functional connectivity development within and beyond the frontoparietal network, these findings indicate that the first 3 years constitute a crucial period for EF development. Ongoing and future research in larger and more diverse longitudinal cohorts, incorporating multimodal imaging and more consistent and targeted behavioral tasks, will further elucidate the unfolding of EF during the earliest childhood years.