Effect of the static magnetic field of the MR-scanner on ERPs : evaluation of visual, cognitive and motor potentialsEffect of the static magnetic field of the MR-scanner on ERPs : evaluation of visual, cognitive and motor potentials
Faculty of Medicine and Health Sciences
Molecular Imaging, Pathology, Radiotherapy & Oncology (MIPRO)
Clinical neurophysiology. - Amsterdam
121(2010):5, p. 672-685
Objective This work investigates the influence of the static magnetic field of the MR-scanner on ERPs extracted from simultaneous EEGfMRI recordings. The quality of the ERPs after BallistoCardioGraphic (BCG) artifact removal, as well as the reproducibility of the waveforms in different environments is investigated. Methods We consider a Detection, a GoNogo and a Motor task, eliciting peaks that differ in amplitude, latency and scalp topography, repeated in two situations: outside the scanner room (0 T) and inside the MR-scanner but without gradients (3 T). The BCG artifact is removed by means of three techniques: the Average Artifact Subtraction (AAS) method, the Optimal Basis Set (OBS) method and the Canonical Correlation Analysis (CCA) approach. Results The performance of the three methods depends on the amount of averaged trials. Moreover, differences are found on both amplitude and latency of ERP components recorded in two environments (0 T vs 3 T). Conclusions We showed that, while ERPs can be extracted from simultaneous EEGfMRI data at 3 T, the static magnetic field might affect the physiological processes under investigation. Significance The reproducibility of the ERPs in different recording environments (0 T vs 3 T) is a relevant issue that deserves further investigation to clarify the equivalence of cognitive processes in both behavioral and imaging studies.