Vision, CentralVisual evoked potential (VEP) measured by simultaneous 64-channel EEG and 3T fMRIBonmassar, G1,3; Anami, K1; Ives, J2; Belliveau, J W.1Author Information 1NMR Center, Massachusetts General Hospital, Charlestown, MA 02129 2Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. 3Corresponding Author: G. Bonmassar ACKNOWLEDGEMENTS: This study was supported by grants from the Whitaker Foundation, United States Public Health Service NIH RO1 NS37462, and conducted during the tenure of an Established Investigatorship from the American Heart Association to J.W.B. We acknowledge the insightful comments of Anders Dale, and the Salk Institute for the use of the ICA toolbox. Received 23 March 1999; accepted 24 April 1999 NeuroReport: June 23rd, 1999 - Volume 10 - Issue 9 - p 1893-1897 Buy Abstract WE present the first simultaneous measurements of evoked potentials (EPs) and fMRI hemodynamic responses to visual stimulation. Visual evoked potentials (VEPs) were recorded both inside and outside the static 3 T magnetic field, and during fMRI examination. We designed, constructed, and tested a non-magnetic 64-channel EEG recording cap. By using a large number of EEG channels it is possible to design a spatial filter capable of removing the artifact noise present when recording EEG/EPs within a strong magnetic field. We show that the designed spatial filter is capable of recovering the ballistocardiogram-contaminated original EEG signal. Isopotential plots of the electrode array recordings at the peak of the VEP response (˜100 ms) correspond well with simultaneous fMRI observed activated areas of primary and secondary visual cortices. © 1999 Lippincott Williams & Wilkins, Inc.