Frontal fNIRS Activity Predicts Performance Differently across Levels of Cognitive Load

fNIRS data were collected while participants completed an n-back task with varying cognitive load. Extensive fronto-parietal activation changes were related to n-back level irrespective of performance. Activation in mid-frontal channels differentially related to accuracy depending on load, suggesting a trade-off between automaticity and engagement as a function of task difficulty.