Subliminal Convergence of Kanji and Kana Words: Further Evidence for Functional Parcellation of the Posterior Temporal Cortex in Visual Word Perception

Abstract

Abstract& Recent evidence has suggested that the human occipitotemporal region comprises several subregions, each sensitive to a distinct processing level of visual words. To further explore the functional architecture of visual word recognition, we employed a subliminal priming method with functional magnetic resonance imaging (fMRI) during semantic judgments of words presented in two different Japanese scripts, Kanji and Kana. Each target word was preceded by a subliminal presentation of either the same or a different word, and in the same or a different script. Behaviorally, word repetition produced significant priming regardless of whether the words were presented in the same or different script. At the neural level, this cross-script priming was associated with repetition suppression in the left inferior temporal cortex anterior and dorsal to the visual word form area hypothesized for alphabetical writing systems, suggesting that cross-script convergence occurred at a semantic level. fMRI also evidenced a shared visual occipito-temporal activation for words in the two scripts, with slightly more mesial and right-predominant activation for Kanji and with greater occipital activation for Kana. These results thus allow us to separate script-specific and script-independent regions in the posterior temporal lobe, while demonstrating that both can be activated subliminally. &

Language experience shapes fusiform activation when processing a logographic artificial language: An fMRI training study

“…Because the two words share the same phonology and semantic identity, it is possible that the priming effect occurs at the phonological and/or semantic level, but not at the pre-lexical abstract visual word level. Consistent with this view, previous research also showed cross-language (Chee et al, 2003) and cross-script (Nakamura et al, 2005) priming effect in the fusiform region, but as well as in several other language areas. Thus, the exact mechanisms for how language experiences modulate the priming effect in fusiform cortex need to be elucidated.…”

Breaking the symmetry: Mirror discrimination for single letters but not for pictures in the Visual Word Form Area

“…That is, it no longer showed repetition suppression when a word was preceded by a mirror-image version of itself. This region is known to adapt to orthographic stimuli during reading acquisition across different cultures (Cohen et al, 2000;McCandliss, 2003;Nakamura et al, 2005;Maurer et al, 2008;Dehaene, 2009;Graves et al, 2010), and it was therefore concluded that it may be the site of the loss of mirror invariance which occurs in young children and seems to be needed for efficient reading in alphabetic scripts.…”

Task-specific change of unconscious neural priming in the cerebral language network

“…For instance, a shape-invariant neural code for letter strings has been found at the left middle fusiform gyrus (FG) showing response attenuation to the repeated presentation of words and word roots, whereas a more anterolateral sector of the posterior temporal cortex exhibits sensitivity to semantic-level representations (5). For nonalphabetic languages, the repetition of logographic Kanji elicits a similar neural adaptation at the left middle temporal gyrus (MTG) associated with semantic knowledge (6).…”

“…1A). For Japanese readers, unconscious priming occurs even when the same word is repeated across Kanji and Kana formats, such as " " and '' '' (6). Because these logographic and syllabic scripts have no mutual correspondence at the subword level, this ''cross-script priming'' paradigm targets the cognitive locus of across-script convergence between the two writing systems, allowing us to isolate the neural codes associated with higher-order, abstract-level representation beyond orthography.…”

“…That is, masked repetition priming during reading aloud has been attributed to either the orthography-to-phonology computation (11) or further downstream to the motor-articulatory codes (12). By contrast, repetition priming during categorization reflects the unconscious activation of lexicosemantic knowledge (6), and may also involve a motor representations of the manual response (4). We further examined the influence of cognitive sets on the cerebral language network by computing the effective connectivity between the brain structures showing task-specific priming effects.…”