Language-specific cortical activation patterns for verbal fluency tasks in Japanese as assessed by multichannel functional near-infrared spectroscopy
Description
In Japan, verbal fluency tasks are commonly utilized as a standard paradigm for neuropsychological testing of cognitive and linguistic abilities. The Japanese "letter fluency task" is a mora/letter fluency task based on the phonological and orthographical characteristics of the Japanese language. Whether there are similar activation patterns across languages or a Japanese-specific mora/letter fluency pattern is not certain. We investigated the neural correlates of overt mora/letter and category fluency tasks in healthy Japanese. The category fluency task activated the bilateral fronto-temporal language-related regions with left-superior lateralization, while the mora/letter fluency task led to wider activation including the inferior parietal regions (left and right supramarginal gyrus). Specific bilateral supramarginal activation during the mora/letter fluency task in Japanese was distinct from that of similar letter fluency tasks in syllable-alphabet-based languages: this might be due to the requirement of additional phonological processing and working memory, or due to increased cognitive load in general.
Journal
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- Brain and Language
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Brain and Language 126 (2), 208-216, 2013-08
Elsevier BV