Changhao Xiong¹, Sungkean Kim², Qiang Yang¹, Srinivasan Meyyappan³, George Mangun³⁴, Mingzhou Ding¹; ¹J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, ²Department of Human-Computer Interaction, Hanyang University, ³Center for Mind and Brain, University of California, Davis, ⁴Departments of Psychology and Neurology, University of California, Davis

It is well established that ongoing alpha oscillations (8 to 12 Hz) influence visual stimulus processing. In this study, we investigated whether and how ongoing alpha oscillations biased decision making in willed attention. Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data were recorded from participants performing a cued visual spatial attention task. Each trial started with one of three cues. Two of them instructed the participant to covertly attend a spatial location in the left or the right visual field (instructed attention). The third cue prompted the participant to spontaneously decide which spatial location to covertly attend (willed attention). Following a variable cue-target interval, the participant discriminated the spatial frequency of a grating appearing at the attended location and ignored the grating appearing at the unattended location. Subjecting the distributed pattern of EEG alpha-band power in the pre-cue time period (-500 to 0 ms) to multivariate pattern analysis (MVPA), we found that (1) for instructed attention, the accuracy of decoding the direction of attention was at chance level, as expected and (2) for willed attention, however, the accuracy of decoding the direction of attention was significantly above chance level and significantly correlated with the cue-evoked fMRI activities in the salience and the central executive networks. These results revealed that (1) ongoing alpha oscillations biased decision making in willed attention and (2) it was doing so by modulating the activity in the frontoparietal decision-making networks.