Investigating the effect of modifying the EEG cap lead configuration on the gradient artifact in simultaneous EEG-fMRI.

ABSTRACT: EEG data recorded during simultaneous fMRI are contaminated by large voltages generated by time-varying magnetic field gradients. Correction of the resulting gradient artifact (GA) generally involves low-pass filtering to attenuate the high-frequency voltage fluctuations of the GA, followed by subtraction of a GA template produced by averaging over repeats of the artifact waveforms. This average artifact subtraction (AAS) process relies on the EEG amplifier having a large enough dynamic range to characterize the artifact voltages and on invariance of the artifact waveform over repeated image acquisitions. Saturation of the amplifiers and changes in subject position can leave unwanted residual GA after AAS. Previous modeling work suggested that modifying the lead layout and the exit positio

SUBMITTER: Mullinger KJ 

PROVIDER: S-EPMC4114285 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature