Wearable functional near-infrared spectroscopy for measuring dissociable activation dynamics of prefrontal cortex subregions during working memory

The prefrontal cortex (PFC) has been extensively studied in relation to various cogni-tive abilities, including executive function, attention, and memory. Nevertheless,there is a gap in our scientific knowledge regarding the functionally dissociable neuraldynamics across the PFC during a cognitive task and their individual differences inperformance. Here, we explored this possibility using a delayed match-to-sample(DMTS) working memory (WM) task using NIRSIT, a high-density, wireless, wearablefunctional near-infrared spectroscopy (fNIRS) system. First, upon presentation of thesample stimulus, we observed an immediate signal increase in the ventral (orbitofron-tal) region of the anterior PFC, followed by activity in the dorsolateral PFC. After theDMTS test stimulus appeared, the orbitofrontal cortex activated once again, whilethe rest of the PFC showed overall disengagement. Individuals with higher accuracyshowed earlier and sustained activation of the PFC across the trial. Furthermore,higher network efficiency and functional connectivity in the PFC were correlatedwith individual WM performance. Our study sheds new light on the dynamics of PFCsubregional activity during a cognitive task and its potential applicability in explainingindividual differences in experimental, educational, or clinical populations.