title: A new method for magnetoencephalography: a three-dimensional magnetometer-spatial filter system.
abstract: A novel three-dimensional magnetometer-spatial filter system was developed to study human brain activity with high spatiotemporal resolution. The system combines the high temporal resolution of magnetoencephalography with the high spatial resolution achieved by using three-dimensional magnetometers and spatial filters to measure the direction and intensity of magnetic fields generated during brain activity. Simulation and phantom studies indicate that the system is capable of mapping current sources of magnetic fields with a spatial resolution comparable to that of any other brain functional imaging technique while maintaining millisecond temporal resolution. Application of this system to the human brain resolved magnetoencephalographic responses evoked by motion stimuli on a millisecond scale into responses occurring in visual cortical areas V1, V2/3 and V5. It also revealed signals related to contextual modulation in V1 and V2/3. This system provides a new way of studying the dynamics of human brain function.
authors.affiliation: Department of Physiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Toyama
authors.forename: K
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Y
authors.initials: Y
authors.lastname: Kondo
authors.forename: S
authors.initials: S
authors.lastname: Tomita
authors.forename: Y
authors.initials: Y
authors.lastname: Takanashi
authors.forename: Y
authors.initials: Y
authors.lastname: Ejima
authors.forename: S
authors.initials: S
authors.lastname: Yoshizawa
mesh_terms: D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D005071:Evoked Potentials; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015225:Magnetoencephalography / Q000295:instrumentation* / Q000379:methods*; D019047:Phantoms, Imaging; D014793:Visual Cortex / Q000502:physiology