To investigate the characteristics of brain activation in the prefrontal and parietal cortices under varying attention levels using functional near-infrared spectroscopy (fNIRS) in order to provide data for real-time attention monitoring.

Hemodynamic responses of oxygenated hemoglobin were recorded from 45 healthy participants during the psychomotor vigilance task (PVT). The fastest 10% of reaction times were defined as the high-attention state while the slowest 10% were defined as the low-attention state. Changes in oxyhemoglobin concentration (ΔHbO) and their time-domain parameters were compared between these states. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic value.

The dorsolateral prefrontal cortex, primary motor cortex, and premotor cortex showed significantly stronger activation in the high-attention state. Analysis of characteristic parameters revealed that integral values, linear slopes and centroid values were higher in the high-attention state than in the low-attention state. Notably, the integral value of the dorsolateral prefrontal cortex was moderately accurate in monitoring attention (AUC=0.710).

The integral value of oxyhemoglobin in the dorsolateral prefrontal cortex may serve as a potential biomarker for attention assessment. This finding offers key parameters for real-time, dynamic attention monitoring using fNIRS.