Brain activation using triggered event-related fMRI.
EEG-triggered fMRI provides a method for localizing the sources of brain electrical activity, such as epileptic discharges. Extending single-image acquisitions, following an event on the EEG, into triggered image series acquisitions may allow BOLD time courses to be obtained, such as those observed in event-related (ER) fMRI experiments. However, in contrast to the standard ER-fMRI, triggered image series are greatly affected by magnetization non-steady-state effects. The purpose of this paper is to show that the BOLD responses can be recovered using subtraction between two triggered image series having different functional contrasts. In order to evaluate this technique, a comparison with standard ER-fMRI using motor cortex activation task was made in 5 volunteers. We conclude that this can be a useful technique for studying brain activation associated with irregularly appearing stimuli.
Zimine
Ivan
I
Department of Radiology, Geneva University Hospitals, 24 rue Micheli-du-Crest, 1211 Geneva 14, Switzerland. Ivan.Zimine@dim.hcuge.ch
Seghier
Mohamed L
ML
Seeck
Margitta
M
Lazeyras
François
F
D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009044:Motor Cortex / Q000098:blood supply / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D013382:Subtraction Technique