title: Real-time artifact filtering in continuous VEPs/fMRI recording.
abstract: 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.
authors.affiliation: 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
authors.forename: Muhammad Nabeel
authors.initials: MN
authors.lastname: Anwar
authors.forename: Laura
authors.initials: L
authors.lastname: Bonzano
authors.forename: Davide Rossi
authors.initials: DR
authors.lastname: Sebastiano
authors.forename: Luca
authors.initials: L
authors.lastname: Roccatagliata
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gualniera
authors.forename: Paolo
authors.initials: P
authors.lastname: Vitali
authors.forename: Carla
authors.initials: C
authors.lastname: Ogliastro
authors.forename: Luciano
authors.initials: L
authors.lastname: Spadavecchia
authors.forename: Guido
authors.initials: G
authors.lastname: Rodriguez
authors.forename: Vittorio
authors.initials: V
authors.lastname: Sanguineti
authors.forename: Pietro
authors.initials: P
authors.lastname: Morasso
authors.forename: Fabio
authors.initials: F
authors.lastname: Bandini
mesh_terms: 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*