Orthographic influences on division of labor in learning to read Chinese and English: Insights from computational modeling

Electrophysiological markers of orthographic pattern learning in school-aged children with reading challenges: An ERP investigation

BACKGROUND

Previous studies suggested that children with reading difficulty have impaired statistical learning ability in extracting distributional orthographic regularities. However, the neural mechanisms underlying have not been fully investigated.

AIMS

The current study aimed to identify the electrophysiological markers and to examine the neural underpinnings of statistical learning of orthographic regularities in children with reading difficulties.

METHODS AND PROCEDURES

Using the event-related potentials (ERPs) and the orthographic learning task, 157 children were exposed to a sequence of artificial pseudocharacters with varying levels of positional and semantic consistency (low at 60 %, moderate at 80 %, and high at 100 %).

OUTCOMES AND RESULTS

Poor readers elicited an increased N170 response in the low consistency and a lack of left-lateralized P300 effect when learning positional regularities of radicals. Similarly, larger N170 effects were observed in poor readers, while similar N400 effects were found in both poor and average readers when learning semantic regularities of radicals.

CONCLUSIONS AND IMPLICATIONS

Our findings indicate that poor readers may have trouble using statistical information for early-stage orthographic pattern extraction, yet they can identify semantic inconsistencies after sufficient exposure. These results deepen our understanding of the neural mechanisms involved in statistical learning for poor readers and aid in improving criteria for differentiating between typically developing children and those with reading challenges.

The phonological congruency modulated long-term form priming of Chinese characters

Elucidating the interaction between lexical processing and word learning is essential for a complete understanding of the underlying mechanisms of each of them. Long-term priming for words reflects an interplay between lexical processing and word learning. Although robust long-term priming effects have been found between two occurrences of the same word and between semantically similar words, it remains unclear whether long-term priming between orthographically similar words (i.e., long-term form priming) is a reliable effect. Following the theoretical analysis based on the connectionist framework, we articulated the possibility that long-term form priming might be modulated by the phonological congruency between the prime and target words, and that if this modulator was under control, reliable effects of long-term form priming would emerge. However, this hypothesis has not been adequately tested empirically. The present study tested this hypothesis by using Chinese phonograms and the phonetic radicals embedded in them as the prime and target items. In three experiments that varied in the types of stimuli and testing tasks, we consistently found that when the prime and target had the same phonology, naming the prime facilitated later processing of the target, while when they had different phonologies, the priming effect was inhibitory. These observations were consistent with the connectionist account of long-term priming for words. Our findings help confirm the reliability, generalizability, and robustness of long-term form priming and elucidate its underlying mechanisms, and suggesting promising future directions on the interactions between lexical processing and word learning.

Does Nonlinguistic Segmentation Predict Literacy in Second Language Education? Statistical Learning in Ivorian Primary Schools

Statistical learning (SL) is a learning mechanism that does not directly depend on knowledge of a language, but predicts language and literacy outcomes for children and adults. Research linking SL and literacy has not addressed children who first learn to read in their second language (L2), common in primary schools worldwide. Several studies have linked SL with childhood literacy in Australia, China, Europe, and the U.S., and we pre-registered an adaptation for Côte d'Ivoire, where students are educated in French and speak a local language at home. Recruiting 117 sixth-graders from primary schools in several villages, we tested for correlations >0.3 between SL and literacy with 80-90% power. We found no evidence for these correlations, but visual SL was correlated with L2 phonological awareness. Although this finding may suggest a role of SL in emergent L2 skills, it underscores the need to include L2 acquisition contexts in literacy research.

Struggling with L2 alphabet: The role of proficiency in orthographic learning

The present study examined the process of L2 orthographic learning in bilinguals with distant L1-L2 orthographies. Chinese-English bilinguals with various English proficiency levels were trained with novel L2 words during a reading task. In contrast to higher proficient learners, those with lower L2 proficiency exhibited increased effects of length, frequency, and lexicality across exposures and at-chance recognition of trained words. Importantly, an additional post-training task assessing the lexical integration of trained words evidenced the engagement in different L1-L2 reading strategies across different levels of L2 proficiency, hence suggesting the L1 holistic processing at the base of the effortful establishment of L2 orthographic representations shown by lower-proficient learners. Overall, these findings indicate the role of L2 proficiency in the influence that cross-linguistic variation exerts on L2 orthographic learning and highlight the need for English education programmes to tackle specific grapheme-to-phoneme skills in non-alphabetic target communities.

Literacy and early language development: Insights from computational modelling

Computational models of reading have tended to focus on the cognitive requirements of mapping among written, spoken, and meaning representations of individual words in adult readers. Consequently, the alignment of these computational models with behavioural studies of reading development has to date been limited. Models of reading have provided us with insights into the architecture of the reading system, and these have recently been extended to investigate literacy development, and the early language skills that influence children's reading. These models show us: how learning to read builds on early language skills, why various reading interventions might be more or less effective for different children, and how reading develops across different languages and writing systems. Though there is growing alignment between descriptive models of reading behaviour and computational models, there remains a gap, and I lay out the groundwork for how translation may become increasingly effective through future modelling work.

Culture is not destiny, for reading: highlighting variable routes to literacy within writing systems

Cross-writing system research in psychology and cognitive neuroscience has yielded important findings regarding how a writing system's structure can influence the cognitive challenges of learning to read and the neural underpinnings of literacy. The current paper reviews these differences and extends the findings to demonstrate diversity in how skilled reading is accomplished within a single writing system, English. We argue that broad clusters of behavioral and neural patterns found across writing systems can also be found within subpopulations who display atypical routes to skilled English reading, subpopulations including Chinese-English bilinguals, deaf native signers, compensated readers, and distortion-sensitive readers. The patterns of interest include a tradeoff between the degree of reliance on phonological and morphological processing for skilled reading, a shift in attentional focus from smaller to larger orthographic units, and enhanced bilaterality of neural processing during word reading. Lastly, we consider how understanding atypical routes to reading may apply to other writing systems.

Atypical Relationships Between Neurofunctional Features of Print-Sound Integration and Reading Abilities in Chinese Children With Dyslexia

Conquering print-sound mappings (e.g., grapheme-phoneme correspondence rules) is vital for developing fluent reading skills. In neuroimaging research, this ability can be indexed by activation differences between audiovisual congruent against incongruent conditions in brain areas such as the left superior temporal cortex. In line with it, individuals with dyslexia have difficulty in tasks requiring print-sound processing, accompanied by a reduced neural integration. However, existing evidence is almost restricted to alphabetic languages. Whether and how multisensory processing of print and sound is impaired in Chinese dyslexia remains underexplored. In this study, we applied a passive audiovisual integration paradigm with functional magnetic resonance imaging to investigate the possible dysfunctions in processing character-sound (opaque; semantics can be automatically accessed) and pinyin-sound associations (transparent; no particular meaning can be confirmed) in Chinese dyslexic children. Unexpectedly, the dyslexic group did not show reduced neural integration compared with typically developing readers in either character or pinyin experiment. However, the results revealed atypical correlations between neural integration and different reading abilities in dyslexia. Specifically, while the neural integration in the left inferior frontal cortex in processing character-sound pairs correlated with silent reading comprehension in both children with and without dyslexia, it was associated with morphological awareness (semantic-related) in controls but with rapid naming (phonological-related) in dyslexics. This result indicates Chinese dyslexic children may not use the same grapho-semantic processing strategy as their typical peers do. As for pinyin-sound processing, while a stronger neural integration in the direction of "congruent > incongruent" in the left occipito-temporal cortex and bilateral superior temporal cortices was associated with better oral reading fluency in the control group, an opposite pattern was found in dyslexia. This finding may reflect dyslexia's dysfunctional recruitment of the regions in grapho-phonological processing, which further impedes character learning.

Order processing of number symbols is influenced by direction, but not format

This study probed the cognitive mechanisms that underlie order processing for number symbols, specifically the extent to which the direction and format in which number symbols are presented influence the processing of numerical order, as well as the extent to which the relationship between numerical order processing and mathematical achievement is specific to Arabic numerals or generalisable to other notational formats. Seventy adults who were bilingual in English and Chinese completed a Numerical Ordinality Task, using number sequences of various directional conditions (i.e., ascending, descending, mixed) and notational formats (i.e., Arabic numerals, English number words, and Chinese number words). Order processing was found to occur for ascending and descending number sequences (i.e., ordered but not non-ordered trials), with the overall pattern of data supporting the theoretical perspective that the strength and closeness of associations between items in the number sequence could underlie numerical order processing. However, order processing was found to be independent of the notational format in which the numerical stimuli were presented, suggesting that the psychological representations and processes associated with numerical order are abstract across different formats of number symbols. In addition, a relationship between the processing speed for numerical order judgements and mathematical achievement was observed for Arabic numerals and Chinese number words, and to a weaker extent, English number words. Together, our findings have started to uncover the cognitive mechanisms that could underlie order processing for different formats of number symbols, and raise new questions about the generalisability of these findings to other notational formats.

Predicting language treatment response in bilingual aphasia using neural network-based patient models

Predicting language therapy outcomes in bilinguals with aphasia (BWA) remains challenging due to the multiple pre- and poststroke factors that determine the deficits and recovery of their two languages. Computational models that simulate language impairment and treatment outcomes in BWA can help predict therapy response and identify the optimal language for treatment. Here we used the BiLex computational model to simulate the behavioral profile of language deficits and treatment response of a retrospective sample of 13 Spanish-English BWA who received therapy in one of their languages. Specifically, we simulated their prestroke naming ability and poststroke naming impairment in each language, and their treatment response in the treated and the untreated language. BiLex predicted treatment effects accurately and robustly in the treated language and captured different degrees of cross-language generalization in the untreated language in BWA. Our cross-validation approach further demonstrated that BiLex generalizes to predict treatment response for patients whose data were not used in model training. These findings support the potential of BiLex to predict therapy outcomes for BWA and suggest that computational modeling may be helpful to guide individually tailored rehabilitation plans for this population.

Reciprocal effects of morphological awareness, vocabulary knowledge, and word reading: A cross-lagged panel analysis in Chinese

There are strong correspondences among syllable, morpheme, and orthographic representations in Chinese. For this reason, bidirectional relationships have been hypothesized among morphological awareness, vocabulary knowledge, and word reading from an early age. Our study examined the reciprocity of these skills among Hong Kong Chinese primary school children. Data were collected from 160 first graders at two time points and were analyzed using a cross-lagged panel design with the three skills modeled simultaneously. No reciprocal pathways were demonstrated in the model; instead, unidirectional relationships emerged. Morphological awareness facilitated later word reading, and word reading facilitated later vocabulary knowledge. Results are discussed in relation to a developmental account of learning to read in Chinese.

The Impact of Different Writing Systems on Children's Spelling Error Profiles: Alphabetic, Akshara, and Hanzi Cases

The importance of literacy in academics and the predominantly digital world cannot be understated. The literacy component of writing is less researched than that of reading, even though it holds equal significance for modern success. Spelling is an important aspect of the construct of literacy, and is more difficult to acquire than reading. Previous work on spelling error analysis for English provides insight into the sets of knowledge and cognitive processes required for children to perform the task, and their different strategies across development. However, different sets of skills and strategies may contribute to spelling across types of orthographies. In this study, we extend spelling error analysis to groups of biliterate children learning two scripts, which include English plus either: (a) another Latin-script alphabet with a shallow orthography (Malay); (b) a transparent alphasyllabary using akshara (Tamil); or (c) a non-alphabetic, morphosyllabic script using simplified hanzi characters (Mandarin Chinese). These sets of scripts vary in how speech is mapped to print. We utilized an error coding scheme based on triple-code theory to enumerate the occurrence of phonological, orthographic (graphemic), and morphological (semantic) types of spelling errors across the three language groups. Five hundred and sixty-eight Grade 1, 6-year-old children participated, with 128 English + Malay, 119 English + Tamil, and 321 English + Chinese children in each bilingual group. They completed a spelling to dictation task in their Asian language, with ten words taken from the grade level curriculum per language. Results indicate group differences in the proportions of error types, with more overall errors for Tamil, more phonological errors for Malay, and more irrelevant or non-sense words for Chinese. The implications are that different scripts present different challenges for young learners.

Linking Behavioral and Computational Approaches to Better Understand Variant Vowel Pronunciations in Developing Readers

The overarching goal of the new Florida State University/Haskins Laboratory/University of Connecticut Learning Disability (LD) Hub project is to align computational and behavioral theories of individual word reading development more closely with the challenges of learning to read a quasi-regular orthography (i.e., English) for both typically developing (TD) children and, more specifically, children with dyslexia. Our LD Hub adopts an integrated approach to better understand the neurocognitive bases of individual differences in word reading development by specifically examining the experiential (exogenous) and child-specific (endogenous) factors that determine acquisition of orthographic-phonological knowledge at different subword granularities using behavioral and computational modeling. Findings are intended to enrich understanding of the processes that influence individual differences in word reading development in TD and dyslexic children and significantly inform issues of practice (e.g., curriculum, instruction, diagnosis, and intervention). Here, we briefly provide the rationale for the Hub and present findings from the initial behavioral and computational modeling studies.

The Interaction Between Phonological and Semantic Processing in Reading Chinese Characters

The contemporary models of visual word recognition reached a consensus on a cooperative division of labor between phonological and semantic processing. We examine how reading is influenced by the interaction of two processing in Chinese character reading since the ideographic property of the Chinese writing system is perfectly suitable to address this issue. The current study investigated whether Chinese character reading requires the interaction between orthography-to-phonology consistency and semantic processing of the whole character (imageability, Experiment 1) or the semantic radical (transparency, Experiment 2). Experiment 1 showed a significant effect of the consistency and a marginal effect of the imageability, but no interaction between the two. Experiment 2 found a significant effect of the semantic transparency and its interaction with phonological consistency, where the transparent effect was significant for inconsistent characters but not for consistent ones. The current finding provided direct evidence of the interplay between phonological and semantic processing and shed light on the language-general reading model.

Orthographic and Phonological Representations in the Fusiform Cortex

Mental and neural representations of words are at the core of understanding the cognitive and neural mechanisms of reading. Despite extensive studies, the nature of visual word representation remains highly controversial due to methodological limitations. In particular, it is unclear whether the fusiform cortex contains only abstract orthographic representation, or represents both lower and higher level orthography as well as phonology. Using representational similarity analysis, we integrated behavioral ratings, computational models of reading and visual object recognition, and neuroimaging data to examine the nature of visual word representations in the fusiform cortex. Our results provided clear evidence that the middle and anterior fusiform represented both phonological and orthographic information. Whereas lower level orthographic information was represented at every stage of the ventral visual stream, abstract orthographic information was increasingly represented along the posterior-to-anterior axis. Furthermore, the left and right hemispheres were tuned to high- and low-frequency orthographic information, respectively. These results help to resolve the long-standing debates regarding the role of the fusiform in reading, and have significant implications for the development of psychological, neural, and computational theories of reading.

Alterations in white matter pathways underlying phonological and morphological processing in Chinese developmental dyslexia

Chinese is a logographic language that is different from alphabetic languages in visual and semantic complexity. Thus far, it is still unclear whether Chinese children with dyslexia show similar disruption of white matter pathways as in alphabetic languages. The present study focused on the alteration of white matter pathways in Chinese children with dyslexia. Using diffusion tensor imaging tractography, the bilateral arcuate fasciculus (AF-anterior, AF-posterior and AF-direct segments), inferior fronto-occipital fasciculus (IFOF) and inferior longitudinal fasciculus (ILF) were delineated in each individual’s native space. Compared with age-matched controls, Chinese children with dyslexia showed reduced fractional anisotropy in the left AF-direct and the left ILF. Further regression analyses revealed a functional dissociation between the left AF-direct and the left ILF. The AF-direct tract integrity was associated with phonological processing skill, an ability important for reading in all writing systems, while the ILF integrity was associated with morphological processing skill, an ability more strongly recruited for Chinese reading. In conclusion, the double disruption locus in Chinese children with dyslexia, and the functional dissociation between dorsal and ventral pathways reflect both universal and specific properties of reading in Chinese.

Statistical and Cooperative Learning in Reading: An Artificial Orthography Learning Study

This paper reports two experiments in which the artificial orthography paradigm was used to investigate the mechanisms underlying learning to read. In each experiment, participants were taught the meanings and pronunications of words written in an unfamiliar orthography and the statistical structure of the mapping between written and spoken forms (O-P) was manipulated independently of the mapping between written forms and their meanings (O-S). Our results support three main conclusions. First, the statistical structure of O-P and O-S mappings determined how easily each of those mappings was learned, suggesting that the learning of both mappings engages a common statistical learning mechnism. Second, learning to read is a cooperative process, in that learning in any particular component of the reading system is influenced by knowledge stored in the rest of the system. Finally, knowledge of sublexical regularities can be acquired as the result of exposure to words embodying those regularities.

Visual sign phonology: insights into human reading and language from a natural soundless phonology

Among the most prevailing assumptions in science and society about the human reading process is that sound and sound-based phonology are critical to young readers. The child's sound-to-letter decoding is viewed as universal and vital to deriving meaning from print. We offer a different view. The crucial link for early reading success is not between segmental sounds and print. Instead the human brain's capacity to segment, categorize, and discern linguistic patterning makes possible the capacity to segment all languages. This biological process includes the segmentation of languages on the hands in signed languages. Exposure to natural sign language in early life equally affords the child's discovery of silent segmental units in visual sign phonology (VSP) that can also facilitate segmental decoding of print. We consider powerful biological evidence about the brain, how it builds sound and sign phonology, and why sound and sign phonology are equally important in language learning and reading. We offer a testable theoretical account, reading model, and predictions about how VSP can facilitate segmentation and mapping between print and meaning. We explain how VSP can be a powerful facilitator of all children's reading success (deaf and hearing)-an account with profound transformative impact on learning to read in deaf children with different language backgrounds. The existence of VSP has important implications for understanding core properties of all human language and reading, challenges assumptions about language and reading as being tied to sound, and provides novel insight into a remarkable biological equivalence in signed and spoken languages. WIREs Cogn Sci 2016, 7:366-381. doi: 10.1002/wcs.1404 For further resources related to this article, please visit the WIREs website.

The Neural Correlates of the Interaction between Semantic and Phonological Processing for Chinese Character Reading

Visual word recognition involves mappings among orthographic, phonological, and semantic codes. In alphabetic languages, it is hard to disentangle the effects of these codes, because orthographically well-formed words are typically pronounceable, confounding orthographic and phonological processes, and orthographic cues to meaning are rare, and where they occur are morphological, confounding orthographic and semantic processes. In Chinese character recognition, it is possible to explore orthography to phonology (O-P) and orthography to semantics (O-S) processes independently by taking advantage of the distinct phonetic and semantic components in Chinese phonograms. We analyzed data from an fMRI experiment using lexical decision for Chinese characters to explore the sensitivity of areas associated with character recognition to orthographic, phonological, and semantic processing. First, a correlation approach was used to identify regions associated with reaction time, frequency, consistency and visual complexity. Then, these ROIs were examined for their responses to stimuli with different types of information available. These results revealed two neural pathways, one for O-S processing relying on left middle temporal gyrus and angular gyrus, and the other for O-P processing relying on inferior frontal gyrus and insula. The two neural routes form a shared neural network both for real and pseudo-characters, and their cooperative division of labor reflects the neural basis for processing different types of characters. Results are broadly consistent with findings from alphabetic languages, as predicted by reading models that assume the same general architecture for logographic and alphabetic scripts.

An Extension of a Parallel-Distributed Processing Framework of Reading Aloud in Japanese: Human Nonword Reading Accuracy Does Not Require a Sequential Mechanism

Humans can pronounce a nonword (e.g., rint). Some researchers have interpreted this behavior as requiring a sequential mechanism by which a grapheme-phoneme correspondence rule is applied to each grapheme in turn. However, several parallel-distributed processing (PDP) models in English have simulated human nonword reading accuracy without a sequential mechanism. Interestingly, the Japanese psycholinguistic literature went partly in the same direction, but it has since concluded that a sequential parsing mechanism is required to reproduce human nonword reading accuracy. In this study, by manipulating the list composition (i.e., pure word/nonword list vs. mixed list), we demonstrated that past psycholinguistic studies in Japanese have overestimated human nonword reading accuracy. When the more fairly reevaluated human performance was targeted, a newly implemented Japanese PDP model simulated the target accuracy as well as the error patterns. These findings suggest that PDP models are a more parsimonious way of explaining reading across various languages.

Introduction to the Special Issue: Advancing the State-of-the-Science in Reading Research through Modeling

Reading research is increasingly a multi-disciplinary endeavor involving more complex, team-based science approaches. These approaches offer the potential of capturing the complexity of reading development, the emergence of individual differences in reading performance over time, how these differences relate to the development of reading difficulties and disability, and more fully understanding the nature of skilled reading in adults. This special issue focuses on the potential opportunities and insights that early and richly integrated advanced statistical and computational modeling approaches can provide to our foundational (and translational) understanding of reading. The issue explores how computational and statistical modeling, using both observed and simulated data, can serve as a contact point among research domains and topics, complement other data sources and critically provide analytic advantages over current approaches.

Towards a Theory of Variation in the Organization of the Word Reading System

The strategy underlying most computational models of word reading is to specify the organization of the reading system-its architecture and the processes and representations it employs-and to demonstrate that this organization would give rise to the behavior observed in word reading tasks. This approach fails to adequately address the variation in reading behavior observed across and within linguistic communities. Only computational models that incorporate learning can fully account for variation in organization. However, even extant learning models (e.g., the triangle model) must be extended if they are to fully account for variation in organization. The challenges associated with extending theories in this way are discussed.

Lexical and sub-lexical reading skills and their correlation to clinical symptoms in young Chinese patients with schizophrenia

Patients with schizophrenia often experience severe reading deficits such as oral reading and reading comprehension deficits. However, it is not known whether different types of lexical or sub-lexical components in reading are also impaired. In order to address this issue, the present study had 22 young Chinese patients with schizophrenia and 22 young Chinese normal controls undergo a battery of reading tests, which specifically measures lexical and sub-lexical components of reading in Chinese. The schizophrenic group further underwent Brief Psychiatric Rating Scale (BPRS) in order to ascertain the severity of patients' clinical symptoms. The results showed that compared to the controls, (1) the schizophrenic patients performed significantly poorly in orthographic processing, orthography-phonology mapping, and orthography-semantic mapping tests and further that (2) their performances in orthographic processing, and orthography-semantic mapping skill tests negatively correlated with the BPRS score. Note however that their ability to access their mental lexicon was intact. There is thus a clear need for studies with a larger sample-size and neurobiological measures which would lead to our better understanding of the behavioral as well as the neural relationships between schizophrenic patients, and their reading processing impairments, thus developing effective reading intervention programs for the schizophrenic patients.

Language differences in the brain network for reading in naturalistic story reading and lexical decision

Differences in how writing systems represent language raise important questions about whether there could be a universal functional architecture for reading across languages. In order to study potential language differences in the neural networks that support reading skill, we collected fMRI data from readers of alphabetic (English) and morpho-syllabic (Chinese) writing systems during two reading tasks. In one, participants read short stories under conditions that approximate natural reading, and in the other, participants decided whether individual stimuli were real words or not. Prior work comparing these two writing systems has overwhelmingly used meta-linguistic tasks, generally supporting the conclusion that the reading system is organized differently for skilled readers of Chinese and English. We observed that language differences in the reading network were greatly dependent on task. In lexical decision, a pattern consistent with prior research was observed in which the Middle Frontal Gyrus (MFG) and right Fusiform Gyrus (rFFG) were more active for Chinese than for English, whereas the posterior temporal sulcus was more active for English than for Chinese. We found a very different pattern of language effects in a naturalistic reading paradigm, during which significant differences were only observed in visual regions not typically considered specific to the reading network, and the middle temporal gyrus, which is thought to be important for direct mapping of orthography to semantics. Indeed, in areas that are often discussed as supporting distinct cognitive or linguistic functions between the two languages, we observed interaction. Specifically, language differences were most pronounced in MFG and rFFG during the lexical decision task, whereas no language differences were observed in these areas during silent reading of text for comprehension.

Language-general and -specific white matter microstructural bases for reading

In the past decade, several studies have investigated language-general and -specific brain regions for reading. However, very limited research has examined the white matter that connects these cortical regions. By using diffusion tensor imaging (DTI), the current study investigated the common and divergent relationship between white matter integrity indexed by fractional anisotropy (FA) and native language reading abilities in 89 Chinese and 93 English speakers. Conjunction analysis revealed that for both groups, reading ability was associated with the FA of seven white matter fiber bundles in two main anatomical locations in the left hemisphere: the dorsal corona radiate/corpus callosum/superior longitudinal fasciculus which might be for phonological access, and the ventral uncinate fasciculus/external capsule/inferior fronto-occipital fasciculus which might be for semantic processing. Contrast analysis showed that the FA of the left temporal part of superior longitudinal fasciculus contributed more to reading in English than in Chinese, which is consistent with the notion that this tract is involved in grapheme-to-phoneme conversion for alphabetic language reading. These results are the first evidence of language-general and -specific white matter microstructural bases for reading.

Neural division of labor in reading is constrained by culture: a training study of reading Chinese characters

Word reading in alphabetic language involves a cortical system with multiple components whose division of labor depends on the transparency of the writing system. To gain insight about the neural division of labor between phonology and semantics subserving word reading in Chinese, a deep non-alphabetic writing system, functional magnetic resonance imaging (fMRI) was used to investigate the effects of phonological and semantic training on the cortical circuitry for oral naming of Chinese characters. In a training study, we examined whether a training task that differentially focused readers' attention on the phonological or semantic properties of a Chinese character changes the patterns of cortical activation that was evoked by that character in a subsequent naming task. Our imaging results corroborate that the cortical regions underlying reading in Chinese largely overlap the left-hemisphere reading system responsible for reading in alphabetic languages, with some cortical regions in the left-hemisphere uniquely recruited for reading in Chinese. However, in contrast to findings from studies of English word naming, we observed considerable overlap in the neural activation patterns associated with phonological and semantic training on naming Chinese characters, which we suggest may reflect a balanced neural division of labor between phonology and semantics in Chinese character reading. The equitable division of labor for Chinese reading might be driven by the special statistical structure of the writing system, which includes equally systematic mappings in the correspondences between written forms and their pronunciations and meanings.

The roles of the "ventral" semantic and "dorsal" pathways in conduite d'approche: a neuroanatomically-constrained computational modeling investigation

Ever since the 19th century, the standard model for spoken language processing has assumed two pathways for repetition—a phonological pathway and a semantic pathway—and this idea has gained further support in the last decade. First, recent in vivo tractography studies have demonstrated both the “dorsal” (via arcuate fasciculus) and “ventral” (via extreme capsule and uncinate fasciculus) pathways connecting from the primary auditory area to the speech-motor area, the latter of which passes through a brain area associated with semantic processing (anterior temporal lobe). Secondly, neuropsychological evidence for the role of semantics in repetition is conduite d'approche, a successive phonological improvement (sometimes non-improvement) in aphasic patients' response by repeating several times in succession. Crucially, conduite d'approche is observed in patients with neurological damage in/around the arcuate fasciculus. Successful conduite d'approche is especially clear for semantically-intact patients and it occurs for real words rather than for non-words. These features have led researchers to hypothesize that the patients' disrupted phonological output is “cleaned-up” by intact lexical-semantic information before the next repetition. We tested this hypothesis using the neuroanatomically-constrained dual dorsal-ventral pathway computational model. The results showed that (a) damage to the dorsal pathway impaired repetition; (b) in the context of recovery, the model learned to compute a correct repetition response following the model's own noisy speech output (i.e., successful conduite d'approche); (c) this behavior was more evident for real words than non-words; and (d) activation from the ventral pathway contributed to the increased rate of successful conduite d'approche for real words. These results suggest that lexical-semantic “clean-up” is key to this self-correcting mechanism, supporting the classic proposal of two pathways for repetition.