Spatial and frequency differences of neuromagnetic activities between the perception of open- and closed-class words.
The present study investigated the spatial and frequency differences of neuromagnetic activities between the perception of open- and closed-class words by using a 275-channel whole head magnetoencephalography (MEG) system. Two groups of words, 110 open-class and 110 closed-class, were presented visually and auditorily simultaneously. The data of 12 healthy subjects were analyzed with synthetic aperture magnetometry (SAM) which can identify the frequency-dependent volumetric distribution of evoked magnetic fields (EMFs). Both vocabulary classes elicited spectral power changes in the left inferior frontal gyrus (Broca's area) and left posterior-superior temporal gyrus (Wernicke's area) within 70-120 Hz. However, the open-class words elicited event-related desynchronization (ERD) while the closed-class words elicited event-related synchronization (ERS) in the two areas within 70-120 Hz. In addition, the open-class words also elicited ERS in the right inferior frontal gyrus, right middle frontal gyrus and right inferior parietal lobe within 1-8 Hz, but the closed-class words only elicited ERD in the right inferior frontal gyrus within 1-8 Hz. Furthermore, there were ERD in the right posterior-superior temporal gyrus within 120-200 Hz for the open-class words, but not for the closed-class words. These results indicate that open- and closed-class words are processed differently in the brain, not only in the anatomical substrates, but also in the frequency range of neuromagnetic activity.
Wang
Yingying
Y
MEG Center, Division of Neurology, Cincinnati Children's Hospital Medical Center, MLC 2015, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA. yingying.wang@cchmc.org
Xiang
Jing
J
Kotecha
Rupesh
R
Vannest
Jennifer
J
Liu
Yinhong
Y
Rose
Douglas
D
Schapiro
Mark
M
Degrauw
Ton
T
D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008280:Magnetics / Q000379:methods; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D014825:Vocabulary; D055815:Young Adult