To snack or not to snack: Using fNIRS to link inhibitory control to functional connectivity in the toddler brain

Abstract

Inhibitory control (IC) emerges in infancy, continues to develop throughout childhood and is linked to later life outcomes such as school achievement, prosocial behavior, and psychopathology. Little, however, is known about the neural processes underpinning IC, especially in 2-year-olds. In this study, we examine functional connectivity (FC) in 2.5-year-olds while recording hemodynamic responses via functional infrared spectroscopy (fNIRS) during a traditional snack delay task. We found that functional connectivity strength between left frontal and parietal cortex and bilateral parietal cortex were positively associated with performance on this task. The current findings present the first neural data for toddlers during this IC task. Further, these data are the first to link this self-regulatory process to differences in brain development within this population.Implications for future directions and work with clinical populations are discussed.

Early executive function development: The first three years

“…The increasing involvement of both hemispheres during an IC task across this age range suggests that greater functional connectivity within and between frontal and parietal regions may support the development of IC. This is further supported by another fNIRS study that showed that 2½-year-old toddlers who performed better in a snack delay task had stronger functional connections between left and right parietal cortices, and between frontal and parietal cortices (Kerr-German et al, 2022).…”

Systematic exploration of task-based functional connectivity analyses for infant fNIRS data: Toward single trial measures of connectivity

“…In practice, functional connectivity can be examined whilst at rest (resting state functional connectivity, e.g., Bulgarelli et al, 2019), and so capturing the correlations between spontaneous fluctuations in neural activity in the absence of a task. It can also be examined whilst a participant is completing a task (i.e., task-based functional connectivity, e.g., Kerr-German et al, 2022), and so measuring correlated neural activity that is modulated based on explicitly presented cognitive demands. There are a number of analytic approaches to task-based functional connectivity.…”

“…The utility of fNIRS to measure resting state functional connectivity in infant populations has been consistently demonstrated across the last two decades (Bulgarelli et al, 2024;Hu et al, 2020;Lu et al, 2010). There is also substantial promise for task-based functional connectivity using fNIRS in the first two years of life (Keehn et al, 2013;Kerr-German et al, 2022;Naoi et al, 2013Naoi et al, , 2022, although currently research is limited in comparison to adult resting state fNIRS studies. This difference may be attributed to the existing difficulties surrounding infant fNIRS data collection (see Baek et al 2023 for a comprehensive discussion), as well as the general challenges of working with infant participants.…”