[Investigation of "reading" with FFT analysis of the beta waves in EEG during "rapid-reading"].
The beta waves in electroencephalograms (EEGs) during "reading" were investigated by means of the Fast Fourier Transform (FFT) analysis method. The subjects who had mastered a "rapid-reading" method, were classified into two groups according to their rapid-reading achievement level: the "under-trained readers" (male 5, female 2) had already acquired the ability of smooth eye movement, but continued to use the mental phonetic process while reading. The "well-trained readers" (male 6, female 2) could understand the contents of the text without resorting to such phonetic process. All subjects were righthanded. The tasks were designed to eliminate the artifact of the eye movement and the electromyogram as much as possible. The EEGs were recorded with twelve channels of the international standard 10-20 electrode system. The relative power value (R.P.V.) was calculated as follows: RPV(%) = [(X-C)/N] x 100(%) where X is the beta 1 or beta 2 power value by FFT analysis while doing tasks, C is the power value while doing control tasks, and N is the value in the resting state with the eyes open. The results were statistically analyzed by paired t-test. The following results were obtained: In both groups; (a) the left angular gyrus was usually activate during the rapid-reading; (b) the Wernicke's center was activated only during reading with the phonetic process; (c) in the well-trained readers the activation of the right visual cortex was associated with some visual imaging during the rapid-reading; (d) in the under-trained readers, the association between the activation of the central frontal area and the rapid-reading was observed. Thus, the following model for "reading" was obtained: Two parallel pathways seem important in the processing of the verbal information presented visually; one relates only to the left angular gyrus where the visual-verbal information is processed directly, and the other relates to the interactive pathway between the left angular gyrus and the Wernicke's center. Moreover, the visual cortex of the non-verbal hemisphere seems to play some role in understanding verbal information.
Yokoyama
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First Department of Physiology, Nippon Medical School, Tokyo, Japan.
D001611:Beta Rhythm; D001931:Brain Mapping; D005133:Eye Movements; D005583:Fourier Analysis; D006801:Humans; D009778:Occipital Lobe / Q000502:physiology; D011932:Reading; D014793:Visual Cortex / Q000502:physiology