2017 Volume 58 Issue 2 Pages 143-151
The aim of this study was to identify activation areas of the brain for reading aloud Japanese words written in Hiragana and Katakana characters in 17 healthy female volunteers (age: 21.4±0.5 y) using functional magnetic resonance imaging (fMRI). The word stimuli had a low or high degree of familiarity. We evaluated activated areas of the brain using statistical parametric mapping 2 (SMP2). The left and right superior frontal, medial frontal, middle temporal, left fusiform, angular and cingulate gyri were activated by reading aloud both Hiragana and Katakana words. Reading aloud Hiragana words activated the precuneus as well as the left and right inferior temporal and left posterior cingulate gyri, whereas reading aloud Katakana words activated the left and right inferior frontal, left inferior temporal, anterior cingulate and right postcentral gyri. The brain was activated 13.1- and 2.7-fold more when reading aloud more and less familiar words, respectively, when written in Hiragana. These results showed that the process involved in reading Hiragana and Katakana comprises the dorsal neural circuit described by Iwata. However, the amount of brain activation differed between reading Hiragana and Katakana aloud, and reading Hiragana was more difficult than reading Katakana.
