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Abstract #2832

Non-Linear Modulation of Both Positive and Negative FMRI Responses to Visual Stimulation by Pre-Stimulus Occipital EEG Alpha Power

MAGNA25Stephen D. Mayhew1, Camillo Porcaro2, Dirk Ostwald3, Andrew P. Bagshaw1

1Birmingham University Imaging Centre, School of Psychology, University of Birmingham, Birmingham, West Mids, United Kingdom; 2Institute of Neuroscience, Newcastle University,, Newcastle upon Tyne, United Kingdom; 3Bernstein Centre for Computational Neuroscience,, Berlin, Germany

We use simultaneous EEG-fMRI to investigate the relationship between ongoing or "baseline" brain activity, as indexed by pre-stimulus EEG alpha (8-13Hz) power, and the magnitude of the BOLD fMRI response to brief visual stimulation. We report a significant reduction of visual PBR and enhancement of auditory NBR in trials preceded by high alpha power, beyond that predicted by a linear model. This study provides new evidence that both PBR and NBR to visual stimulation are nonlinearly dependent upon electrophysiological characteristics of baseline brain activity and that NBR reflects inhibition of non-task related brain areas as indexed by occipital alpha power.