Neural substrates of Hanja (Logogram) and Hangul (Phonogram) character readings by functional magnetic resonance imaging.

The two basic scripts of the Korean writing system, Hanja (the logography of the traditional Korean character) and Hangul (the more newer Korean alphabet), have been used together since the 14th century. While Hanja character has its own morphemic base, Hangul being purely phonemic without morphemic base. These two, therefore, have substantially different outcomes as a language as well as different neural responses. Based on these linguistic differences between Hanja and Hangul, we have launched two studies; first was to find differences in cortical activation when it is stimulated by Hanja and Hangul reading to support the much discussed dual-route hypothesis of logographic and phonological routes in the brain by fMRI (Experiment 1). The second objective was to evaluate how Hanja and Hangul affect comprehension, therefore, recognition memory, specifically the effects of semantic transparency and morphemic clarity on memory consolidation and then related cortical activations, using functional magnetic resonance imaging (fMRI) (Experiment 2). The first fMRI experiment indicated relatively large areas of the brain are activated by Hanja reading compared to Hangul reading. The second experiment, the recognition memory study, revealed two findings, that is there is only a small difference in recognition memory for semantic transparency, while for the morphemic clarity was much larger between Hanja and Hangul. That is the morphemic clarity has significantly more effect than semantic transparency on recognition memory when studies by fMRI in correlation with behavioral study.

Horizontal orthography versus vertical orthography: The effects of writing direction and syllabic format on visual word recognition in Korean Hangul.

The Korean writing system has the flexibility of writing horizontally and vertically as well as two syllabic formats that cannot be found in any other alphabetic script. Consolidating these two characteristics, this study investigated the differential extractions of visual information from the mutilated stimuli of the two syllabic formats of CVC syllables and two writing directions using a lexical decision task. In Experiment 1, the two syllabic formats (i.e., balanced syllables, [Formula: see text] and vertical syllables, [Formula: see text]) were mutilated downwards and upwards (i.e., [Formula: see text] [Formula: see text] respectively), along with whole stimuli, in horizontal writing direction. In Experiment 2, the same stimuli and syllabic formats were mutilated rightwards and leftwards (i.e., [Formula: see text] [Formula: see text] respectively) in vertical writing direction. Linear mixed effects models showed significant syllabic format effects and writing direction effects, indicating an upper-part superiority in horizontal writing and a right-part advantage in vertical writing. In particular, the right-part superiority in vertical writing is different from a left-part advantage found in Chinese characters. While the upper-part superiority is script-universal, the leftward or rightward bias seems to be script-specific, as readers' perceptual integration depends on the nature of orthography.