Predicting N2pc from anticipatory HbO activity during sustained visuospatial attention: a concurrent fNIRS-ERP study

Understanding the properties of attentional control, along with the neural mechanisms subserving them, has long invited intense scrutiny in research groups. However, it has not been demonstrated how the top-down anticipatory hemodynamic activation influences the subsequent attentional processing of targets and distractors. Here, with concurrent fNIRS-ERP recording, we explored the potential contribution of anticipatory oxygenated hemoglobin (HbO) based brain activity to attentional control by examining how HbO influences the subsequent ERP N2pc components assumed to reflect attentional selection. We found that expecting a target led to a larger increase of preparatory HbO response over the visual cortex contralateral to the upcoming target, which was positively correlated with the subsequent target-evoked N2pc amplitude. Further, anticipation concerning the presence of a competing distractor resulted in large and prolonged preparatory HbO signals in the visual cortex contralateral to the distractor, indicating that the salient distractor might be actively suppressed by preparatory top-down attentional control. However, the pre-suppressed distractor still captured part of the attention in the subsequent visual search as revealed by a decrease in the N2pc amplitude, and such a distraction effect on N2pc was negatively correlated with preparatory HbO enhancement contralateral to the anticipated distractor. Overall, each individuals attentional shift to the target and resistance to the distractor measured by ERP is predictable in advance via anticipatory hemodynamic activity in the visual cortex measured by fNIRS.