Activation of lateral extrastriate areas during orthographic processing ofJapanese characters studied with fMRI

We investigated the early orthographic processing in the occipital cortex u sing Japanese morphogram by functional magnetic resonance imaging. Kanji (J apanese morphogram) is one system of character used in the Japanese languag e, each character of which has a specific meaning and pronunciations. To en sure that the effects of the general visual properties of Kanji were exclud ed from Kanji-related activation, we created strict control stimuli, the "s crambled Kanji" that had the same luminance, contrast, and retinotopical si ze as those of the original Kanji. In the Kanji vs scrambled Kanji task, we found significant activation in the left inferior occipital gyrus. However , we found no activation in earlier visual cortices, including the primary visual cortex, indicating that the scrambled Kanji served as an effective c ontrol stimulus for this task. In the Kanji vs blank screen task, much more areas, including earlier visual cortices, were activated. The activation t hat we found in the Kanji vs scrambled Kanji task was compatible with the r esults of previous studies of English letter strings by other groups, sugge sting that the left inferior occipital gyrus plays an essential role in ort hographic processing common to these two different writing systems. (C) 199 9 Academic Press.