The neurovascular coupling in the attention during visual working memory

How to focus attention during visual working memory (vWM) depends on ones ability to filter out distractors and expand the scope of targets. Although the spatiotemporal properties of attention processes in WM are well documented, it is still unclear how the mechanisms of neurovascular coupling (NVC) between electroencephalographic (EEG) signals and hemodynamic activity of attention during vWM. To investigate the NVC mechanism underlying attention during vWM, we recorded simultaneous functional near-infrared spectroscopy (fNIRS) and EEG data when humans were performing cued change-detection tasks. The multimodal data showed that the control and scope processes during vWM were involved in similar temporal profiles of frontal theta event-related synchronization (ERS) and posterior contralateral delay activities (CDA), and revealed similar distributions of hemodynamic activation within the frontal eye fields (FEF) and superior parietal lobule (SPL). These task-related features have a common NVC outcome across individuals: the higher EEG features (theta ERS or CDA amplitude), the greater the increment of local oxygenated hemoglobin (HbO) signals within the FEF and SPL. Moreover, when distractors should be filtered out, EEG-informed NVC is involved in a broader range of brain regions in the frontoparietal network (FPN). These results provided unique neurovascular evidence for the mechanisms of attention scope and control in vWM. Interestingly, there might be a negative relationship between behavioral metrics and theta-informed NVC strengths within the FEF for attention control. On a dynamic basis, the NVC features had higher discriminatory power for predicting behavior than EEG features and fNIRS features alone. Together, these results highlight what multimodal approaches can advance our understanding of the role of attention in vWM and how the fluctuations of NVC are associated with actual behavior.