Poster D10, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Brain Structures Modulating Alpha Oscillations in Anticipatory Spatial Visual Attention: A Simultaneous EEG-fMRI Study
Mingzhou Ding1, Yuelu Liu2, Jesse Bengson2, Haiqing Huang1, George R Mangun2; 1University of Florida, 2University of California at Davis
It is well-established that EEG alpha oscillations (8 – 12 Hz) decrease in amplitude in the visual cortex contralateral to the direction of covert spatial visual attention. What is not well-understood is what brain areas contribute to the attentional modulation of alpha. We addressed this question by recording simultaneous EEG-fMRI in human subjects performing a cued visual-spatial attention task. Correlating post-cue alpha power with concurrently recorded blood-oxygen-level-dependent (BOLD) activity we obtained three main results. First, regions negatively correlated with alpha power mainly included bilateral visual cortex, bilateral intraparietal sulci (IPS), and left middle frontal gyrus (MFG), the latter two being part of the frontoparietal attention control network. Further, in IPS, stronger negative correlations were found for contralateral alpha than ipsilateral alpha, suggesting an enhancement of task-relevant areas via top-down modulation. Second, regions positively correlated with alpha power include the sensorimotor cortices and the default mode network, possibly reflecting a mechanism of active inhibition over task-irrelevant areas. Finally, the degree of alpha lateralization was positively correlated with BOLD in dorsal anterior cingulate cortex (dACC) in both attend-left and attend-right conditions, suggesting that the dACC’s role in goal-oriented behavior is to facilitate attentional set via executive influences over attentional control systems. These results, besides revealing the neural substrates of alpha modulation by attention, also indicate that spatial visual attention involves both selective enhancement of task-relevant cortical areas, and active inhibition of task-irrelevant cortical areas.
Topic Area: ATTENTION: Spatial