Spatiotemporal distributions of brain oscillation during silent reading

Abstract The purpose of this study is to demonstrate the spatiotemporal distributions of event-related desynchronization (ERD) and synchronization (ERS) during silent reading. One hundred of three-character hiragana semantic words were presented serially on a liquid crystal monitor for 3 s, and with intervals of 3 s. Six healthy right-handed subjects were instructed to read them without phonation. The data were measured using whole-head type magnetometer. The current sources were estimated spatiotemporally by synthetic aperture magnetometry (SAM). Changes in the source power between the active state and the control state were analyzed statistically with Student's t values. ERD and ERS were distributed multifocally over both hemispheres including classically language-related regions, and lateralized to the left hemisphere. ERSs tended to be distributed serially from the occipital region via the parieto-temporal region to the frontal region. ERDs tended to be distributed multifocally in parallel. Both serial and parallel processings are suggested to be involved in the silent reading. Spatiotemporal distributions and frequency bands of ERD definitely differed from those of ERS. ERS and ERD might reflect the excitation and inhibition of different Hebbian cell assemblies.

[1]  Norihiko Fujita,et al.  Movement-Related Desynchronization of the Cerebral Cortex Studied with Spatially Filtered Magnetoencephalography , 2000, NeuroImage.

[2]  T. Inouye,et al.  Medial prefrontal cortex generates frontal midline theta rhythm. , 1999, Neuroreport.

[3]  B. Feige,et al.  High-frequency cortical responses reflect lexical processing: an MEG study. , 1996, Electroencephalography and clinical neurophysiology.

[4]  Se Robinson,et al.  Functional neuroimaging by Synthetic Aperture Magnetometry (SAM) , 1999 .

[5]  D. Cheyne,et al.  Neuromagnetic fields preceding unilateral movements in dextrals and sinistrals , 1998, Neuroreport.

[6]  N. Birbaumer,et al.  High-frequency brain activity: Its possible role in attention, perception and language processing , 1997, Progress in Neurobiology.

[7]  Toshiki Yoshimine,et al.  Frequency-dependent spatial distribution of human somatosensory evoked neuromagnetic fields , 2002, Neuroscience Letters.

[8]  N Birbaumer,et al.  Spectral responses in the gamma-band: physiological signs of higher cognitive processes? , 1995, Neuroreport.

[9]  G. Pfurtscheller.  Event-related synchronization (ERS): an electrophysiological correlate of cortical areas at rest. , 1992, Electroencephalography and clinical neurophysiology.

[10]  A D Friederici,et al.  Oscillatory neuromagnetic activity induced by language and non-language stimuli. , 1996, Brain research. Cognitive brain research.

[11]  G. Pfurtscheller,et al.  Event-related cortical desynchronization detected by power measurements of scalp EEG. , 1977, Electroencephalography and clinical neurophysiology.

[12]  T. Inouye,et al.  Theta rhythm increases in left superior temporal cortex during auditory hallucinations in schizophrenia: a case report , 2000, Neuroreport.