Real-time artifact filtering in continuous VEPs/fMRI recording.
Continuous recording of Visual Evoked Potentials (VEPs) and functional Magnetic Resonance Imaging (fMRI) exploits the VEPs high temporal resolution and the fMRI high spatial resolution. In this work, we present a new method of continuous VEPs/fMRI recording to study visual function in seven normal subjects. Our real-time artifact filtering is characterized by a procedure based on an analytical study of echo-planar imaging (EPI) sequence parameters related electro-encephalogram (EEG)-artifact shapes. The magnetic field artifacts were minimized by using a dedicated amagnetic device and by a subtraction algorithm that takes into account the EPI sequence parameters. No significant decrease in signal-to-noise ratio was observed in case of EEG recording simultaneously with MR acquisition; similarly, transient and steady-state VEPs parameters were comparable during fMRI acquisition and in the off-phase of fMRI recording. We also applied this method to one patient with optic neuritis, and, compared with controls, found different results. We suggest that our technique can be reliably used to investigate the function of human visual cortex and properly correlate the electrophysiological and functional neuroimaging related changes.
Anwar
Muhammad Nabeel
MN
Department of Computational Intelligence and Systems Science, Tokyo Institute of Technology, G3-50, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan. nabeel@ito.dis.titech.ac.jp
Bonzano
Laura
L
Sebastiano
Davide Rossi
DR
Roccatagliata
Luca
L
Gualniera
Giovanni
G
Vitali
Paolo
P
Ogliastro
Carla
C
Spadavecchia
Luciano
L
Rodriguez
Guido
G
Sanguineti
Vittorio
V
Morasso
Pietro
P
Bandini
Fabio
F
D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D004568:Electrodiagnosis / Q000295:instrumentation / Q000379:methods; D004569:Electroencephalography / Q000379:methods*; D004582:Electronics, Medical / Q000295:instrumentation / Q000379:methods; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics / Q000295:instrumentation / Q000379:methods; D008297:Male; D009902:Optic Neuritis / Q000175:diagnosis / Q000503:physiopathology; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D012984:Software; D013997:Time Factors; D014795:Visual Pathways / Q000502:physiology*