Prefrontal cortex intrinsic functional connectivity and executive function in early childhood and early adulthood using fNIRS.

Executive function (EF) is crucial for goal-directed behavior and predicts overall wellbeing, academic and interpersonal success. Intrinsic (i.e., non-evoked) resting state functional connectivity (rsFC) during naturalistic paradigms offers insight into neural mechanisms underlying EF. However, few studies have explored EF-rsFC associations using functional near-infrared spectroscopy (fNIRS) across age groups. This cross-sectional study validates a naturalistic viewing paradigm (Inscapes) using fNIRS and examines the link between rsFC in the prefrontal cortex (PFC) and EF in children ages 4-5 and in young adults ages 18-22. Adults were presented with two rsFC paradigms in a counterbalanced within-subjects design: a traditional static crosshair and Inscapes. Representational similarity analysis revealed robustly similar rsFC patterns between the crosshair and Inscapes conditions, and both were associated with EF (Stroop performance). Children were presented with Inscapes to assess rsFC, and exhibited high compliance using fNIRS. Importantly, rsFC assessed with Inscapes in children was associated with EF (Stroop-like Day-Night Task performance). Age-related differences showed intrinsic functional connections within the PFC strengthening over development. This study uses child-friendly, noninvasive optical neuroimaging and a publicly available rsFC paradigm to elucidate the role of the PFC in EF development, illuminating practical methodological approaches to study the developmental trajectory and neural underpinnings of EF.