The Interaction Between Brain Function Asymmetry And Hemisphere In Chinese Glyph Recognition

In the present study, we used a divided visual field paradigm that three character stimuli in an inverted-triangle shape were presented simultaneously to the two visual half-fields to explore the effect of visual complexity of character, measured by number of strokes and number of radicals and spatial frequency of the characters, on brain asymmetry and inter-hemispheric interaction for identifying the character form. In the experiment, subjects were asked to determine whether the form of two characters was visual similar or not.The results of experiment 1 showed that:(1)the stroke number effect and the radical number effect were found only for the within-left field/RH presentation, a significant reversed stroke number effect was for the within-right field/LH presentation; (2) character with one number of radical were better for the within-left field/RH than within-right field/LH presentation, characters with high numbers of strokes was were better for the within-right field/LH than within-left field/RH presentation. These results indicated that:a significant within-left field/RH superiority obtained for characters with one number of radical and a significant within-right field/LH superiority obtained for characters with high numbers of strokes. This asymmetry is consistent with the spatial frequency hypothesis;(3)Performance on the characters with high numbers of strokes was better for the within-field than across-field presentation, performance on the characters with two numbers of radicals was also better for the within-field than across-field presentation.The results of experiment 2 showed that:(1) the stroke number effect and the radical number effect were found only for the within-left field/RH presentation; the spatial frequency effect was found on characters low numbers of strokes,one number of radical and two numbers of radicals;(2) the right hemisphere displays greater efficiency than the left hemisphere at processing characters with low numbers of strokes, the left hemisphere displays greater efficiency than the right hemisphere at processing high number of strokes and two numbers of radicals, this asymmetry is partly consistent with the spatial frequency hypothesis; (3)the processing efficiency of interhemispheric interaction was not performed consists with our prediction.These results indicate that:(1) a significant within-left field/RH superiority was found for the characters with one number of radical, a significant within-right field/LH superiority obtained only for the characters with high numbers of strokes;(2)whenever the characters with low numbers of strokes was high-spatial-frequency components or low-spatial-frequency components, there was always a within-left field/RH superiority, while whenever the characters with high numbers of strokes was high-spatial-frequency components or low-spatial-frequency and whenever the characters with two numbers of radicals, there were always a within-right field/LH superiority, this asymmetry is partly consistent with the spatial frequency hypothesis;(3)the left hemisphere was found a significant spatial frequency effect, while the right hemisphere can better deal with low-spatial-frequency components; (4)the right hemisphere and the left hemisphere could involve differently in the processing of strokes and radicals; (5) maybe the characters we used were simple, there was no efficient interhemispheric interaction.