Intersecting distributed networks support convergent linguistic functioning across different languages in bilinguals.

How bilingual brains accomplish the processing of more than one language has been widely investigated by neuroimaging studies. The assimilation-accommodation hypothesis holds that both the same brain neural networks supporting the native language and additional new neural networks are utilized to implement second language processing. However, whether and how this hypothesis applies at the finer-grained levels of both brain anatomical organization and linguistic functions remains unknown. To address this issue, we scanned Chinese-English bilinguals during an implicit reading task involving Chinese words, English words and Chinese pinyin. We observed broad brain cortical regions wherein interdigitated distributed neural populations supported the same cognitive components of different languages. Although spatially separate, regions including the opercular and triangular parts of the inferior frontal gyrus, temporal pole, superior and middle temporal gyrus, precentral gyrus and supplementary motor areas were found to perform the same linguistic functions across languages, indicating regional-level functional assimilation supported by voxel-wise anatomical accommodation. Taken together, the findings not only verify the functional independence of neural representations of different languages, but show co-representation organization of both languages in most language regions, revealing linguistic-feature specific accommodation and assimilation between first and second languages.

IFNAR1 gene mutation may contribute to developmental stuttering in the Chinese population.

BACKGROUND: Developmental stuttering is the most common form of stuttering without apparent neurogenic or psychogenic impairment. Recently, whole-exome sequencing (WES) has been suggested to be a promising approach to study Mendelian disorders. METHODS: Here, we describe an application of WES to identify a gene potentially responsible for persistent developmental stuttering (PDS) by sequencing DNA samples from 10 independent PDS families and 11 sporadic cases. Sanger sequencing was performed for verification with samples obtained from 73 additional patients with sporadic cases. RESULTS: We first searched for cosegregating variants/candidate genes in a Chinese family (Family 0) by sequencing DNA obtained from 3 affected members and 3 controls. Next, we sequenced DNA samples obtained from 9 additional Chinese families (Families 1-9) with stuttering to verify the identified candidate genes. Intriguingly, we found that two missense variants (Leu552Pro and Lys428Gln) of interferon-alpha/beta receptor 1 (IFNAR1) cosegregated with stuttering in three independent families (Families 0, 5 and 9). Moreover, we found two additional mutations (Gly301Glu and Pro335del) in the IFNAR1 gene in 4 patients with sporadic cases by using WES or Sanger sequencing. Further receptor mutagenesis and cell signaling studies revealed that these IFNAR1 variants may impair the activity of type I IFN signaling. CONCLUSION: Our data indicate that IFNAR1 might be a potential pathogenic gene of PDS in the Chinese population.

Evolutional and developmental anatomical architecture of the left inferior frontal gyrus.

The left inferior frontal gyrus (IFG) including Broca's area is involved in the processing of many language subdomains, and thus, research on the evolutional and human developmental characteristics of the left IFG will shed light on how language emerges and maturates. In this study, we used diffusion magnetic resonance imaging (dMRI) and resting-state functional MRI (fMRI) to investigate the evolutional and developmental patterns of the left IFG in humans (age 6-8, age 11-13, and age 16-18 years) and macaques. Tractography-based parcellation was used to define the subcomponents of left IFG and consistently identified four subregions in both humans and macaques. This parcellation scheme for left IFG in human was supported by specific coactivation patterns and functional characterization for each subregion. During evolution and development, we found increased functional balance, amplitude of low frequency fluctuations, functional integration, and functional couplings. We also observed higher fractional anisotropy values, i.e. better myelination of dorsal and ventral white matter language pathways during evolution and development. We assume that the resting-state functional connectivity and task-related coactivation mapping are associated with hierarchical language processing. Our findings have shown the evolutional and human developmental patterns of left IFG, and will contribute to the understanding of how the human language evolves and how atypical language developmental disorders may occur.

Long-Term Physical Exercise and Mindfulness Practice in an Aging Population.

Previous studies have shown that physical exercise and mindfulness meditation can both lead to improvement in physical and mental health. However, it is unclear whether these two forms of training share the same underlying mechanisms. We compared two groups of older adults with 10 years of mindfulness meditation (integrative body-mind training, IBMT) or physical exercise (PE) experience to demonstrate their effects on brain, physiology and behavior. Healthy older adults were randomly selected from a large community health project and the groups were compared on measures of quality of life, autonomic activity (heart rate, heart rate variability, skin conductance response, respiratory amplitude/rate), immune function (secretory Immunoglobulin A, sIgA), stress hormone (cortisol) and brain imaging (resting state functional connectivity, structural differences). In comparison with PE, we found significantly higher ratings for the IBMT group on dimensions of life quality. Parasympathetic activity indexed by skin conductance response and high-frequency heart rate variability also showed more favorable outcomes in the IBMT group. However, the PE group showed lower basal heart rate and greater chest respiratory amplitude. Basal sIgA level was significantly higher and cortisol concentration was lower in the IBMT group. Lastly, the IBMT group had stronger brain connectivity between the dorsal anterior cingulate cortex (dACC) and the striatum at resting state, as well as greater volume of gray matter in the striatum. Our results indicate that mindfulness meditation and physical exercise function in part by different mechanisms, with PE increasing physical fitness and IBMT inducing plasticity in the central nervous systems. These findings suggest combining physical and mental training may achieve better health and quality of life results for an aging population.

Characteristics of Desertification and Short-Term Effectiveness of Differing Treatments on Shifting Sand Dune Stabilization in an Alpine Rangeland.

: Rangeland desertification is one of the most serious problems threatening the ecological environment and socio-economic development on the eastern Qinghai-Tibet Plateau in China. To combat desertification and reduce its adverse effects, some strategies have been undertaken to stabilize the mobile sand dunes and restore the desertified land. In this study, rangeland desertification with a gradient degree of none, light, medium, severe and extreme was assessed, and short-term effectiveness of different treatments on stabilizing the shifting sand dunes was evaluated by monitoring selected vegetation and soil properties. Results showed that vegetation became thinner and sparser, and soil environment deteriorated significantly under desertification, leading to a poor and low diversity ecosystem. Applying a checkerboard protection strategy in which herb species were planted and using a shrub vegetation planting method without checkerboard protection on mobile dunes for five years, vegetation growth state and soil properties were improved. Soil particles were finer, vegetation restoration was more rapid, and soil nutrient improvement was more apparent at the lower locations of the sand dunes under the checkerboard protection planted with herbs, which performed slightly better in improving soil properties than the shrub planting method alone. A longer time period would be required for vegetation and soils on the sand dunes to be restored to sustain more intensive land use. These findings provide more insight into dune stabilization, allowing effective management in the ecological restoration of desertified rangeland.

ERP indicators of L2 proficiency in word-to-text integration processes.

Studies of bilingual proficiency have largely focused on word and sentence processing, whereas the text level has received relatively little attention. We examined on-line second language (L2) text comprehension in relation to L2 proficiency with ERPs recorded on critical words separated across a sentence boundary from their co-referential antecedents. The integration processes on the critical words were designed to reflect different levels of text representation: word-form, word-meaning, and situational level (Kintsch, 1998). Across proficiency level, bilinguals showed biphasic N400/late positive component (LPC) effects related to word meaning integration (N400) and mental model updating (LPC) processes. More proficient bilinguals, compared with less proficient bilinguals, showed reduced amplitudes in both N400 and LPC when the integration depended on semantic and conceptual meanings. When the integration was based on word repetitions and inferences, both groups showed reduced N400 negativity while elevated LPC positivity. These effects reflect how memory mechanisms (processes and resources) support the tight coupling among word meaning, readers' memory of the text meaning and the referentially-specified meaning of the text. They further demonstrate the importance of L2 semantic and conceptual processing in modulating the L2 proficiency effect on L2 text integration processes. These results align with the assumption that word meaning processes are causal components in variations of comprehension ability for both monolinguals and bilinguals.

Association study of FGF18 with developmental dyslexia in Chinese population.

Developmental dyslexia (DD) is a neurobiological disorder featured by reading disabilities. In recent years, genome-wide approaches provided new perspectives to discover novel candidate genes of DD. In a previous study, rs9313548 located downstream of FGF18 showed borderline genome-wide significant association with DD. Herein, we selected rs9313548 and 11 independent tag single nucleotide polymorphisms covering gene region of FGF18 to perform association analysis with DD among 978 Chinese dyslexic cases and 998 controls recruited from elementary schools. However, we did not observe any single nucleotide polymorphism exceeding significant threshold. Our preliminary results suggested that FGF18 might not be a susceptibility gene for DD in Chinese population.

A Meta-Analytic Study of the Neural Systems for Auditory Processing of Lexical Tones.

The neural systems of lexical tone processing have been studied for many years. However, previous findings have been mixed with regard to the hemispheric specialization for the perception of linguistic pitch patterns in native speakers of tonal language. In this study, we performed two activation likelihood estimation (ALE) meta-analyses, one on neuroimaging studies of auditory processing of lexical tones in tonal languages (17 studies), and the other on auditory processing of lexical information in non-tonal languages as a control analysis for comparison (15 studies). The lexical tone ALE analysis showed significant brain activations in bilateral inferior prefrontal regions, bilateral superior temporal regions and the right caudate, while the control ALE analysis showed significant cortical activity in the left inferior frontal gyrus and left temporo-parietal regions. However, we failed to obtain significant differences from the contrast analysis between two auditory conditions, which might be caused by the limited number of studies available for comparison. Although the current study lacks evidence to argue for a lexical tone specific activation pattern, our results provide clues and directions for future investigations on this topic, more sophisticated methods are needed to explore this question in more depth as well.

A Genome-Wide Association Study Identifies Genetic Variants Associated with Mathematics Ability.

Mathematics ability is a complex cognitive trait with polygenic heritability. Genome-wide association study (GWAS) has been an effective approach to investigate genetic components underlying mathematic ability. Although previous studies reported several candidate genetic variants, none of them exceeded genome-wide significant threshold in general populations. Herein, we performed GWAS in Chinese elementary school students to identify potential genetic variants associated with mathematics ability. The discovery stage included 494 and 504 individuals from two independent cohorts respectively. The replication stage included another cohort of 599 individuals. In total, 28 of 81 candidate SNPs that met validation criteria were further replicated. Combined meta-analysis of three cohorts identified four SNPs (rs1012694, rs11743006, rs17778739 and rs17777541) of SPOCK1 gene showing association with mathematics ability (minimum p value 5.67 × 10-10, maximum ß -2.43). The SPOCK1 gene is located on chromosome 5q31.2 and encodes a highly conserved glycoprotein testican-1 which was associated with tumor progression and prognosis as well as neurogenesis. This is the first study to report genome-wide significant association of individual SNPs with mathematics ability in general populations. Our preliminary results further supported the role of SPOCK1 during neurodevelopment. The genetic complexities underlying mathematics ability might contribute to explain the basis of human cognition and intelligence at genetic level.

Genetic polymorphism of nonsyndromic cleft lip with or without cleft palate is associated with developmental dyslexia in Chinese school-aged populations.

Developmental dyslexia (DD) is a neurodevelopment disorder characterized by reading disabilities without apparent etiologies. Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a structural craniofacial malformation featured by isolated orofacial abnormalities. Despite substantial phenotypic differences, potential linkage between these two disorders has been suggested as prevalence of DD among NSCL/P patients was much higher than that in general populations. Previous neuroimaging studies observed impaired short-term memory in patients with DD and NSCL/P, respectively. Genetic factors have a fundamental role during neurodevelopment and craniofacial morphogenesis but there lacks of evidence to support the linkage between DD and NSCL/P at genetic level. A recent genome-wide association study in Chinese populations identified a number of genetic polymorphisms associated with NSCL/P. Herein, we selected three risk variants of NSCL/P namely rs8049367, rs4791774 and rs2235371, and performed association analysis with DD in a Chinese population consisting 631 elementary school-aged children with 288 dyslexic cases without NSCL/P and 343 healthy controls. After Bonferroni correction for multiple comparisons, the T allele of rs8049367 showed significant association with DD (OR=1.41, P=0.0085). It is an intergenic variant between CREBBP and ADCY9 located at 16p13.3. The CREBBP gene was reported to have an essential role during memory formation, although ADCY9 was involved in dental development. In future studies, understanding functional effects of rs8049367 on CERBBP and ADCY9 might contribute to explain underlying etiologies shared by DD and NSCL/P.

Chinese Character and English Word processing in children's ventral occipitotemporal cortex: fMRI evidence for script invariance.

Learning to read is thought to involve the recruitment of left hemisphere ventral occipitotemporal cortex (OTC) by a process of "neuronal recycling", whereby object processing mechanisms are co-opted for reading. Under the same theoretical framework, it has been proposed that the visual word form area (VWFA) within OTC processes orthographic stimuli independent of culture and writing systems, suggesting that it is universally involved in written language. However, this "script invariance" has yet to be demonstrated in monolingual readers of two different writing systems studied under the same experimental conditions. Here, using functional magnetic resonance imaging (fMRI), we examined activity in response to English Words and Chinese Characters in 1st graders in the United States and China, respectively. We examined each group separately and found the readers of English as well as the readers of Chinese to activate the left ventral OTC for their respective native writing systems (using both a whole-brain and a bilateral OTC-restricted analysis). Critically, a conjunction analysis of the two groups revealed significant overlap between them for native writing system processing, located in the VWFA and therefore supporting the hypothesis of script invariance. In the second part of the study, we further examined the left OTC region responsive to each group's native writing system and found that it responded equally to Object stimuli (line drawings) in the Chinese-reading children. In English-reading children, the OTC responded much more to Objects than to English Words. Together, these results support the script invariant role of the VWFA and also support the idea that the areas recruited for character or word processing are rooted in object processing mechanisms of the left OTC.

Numerical evaluation of the scale problem on the wind flow of a windbreak.

The airflow field around wind fences with different porosities, which are important in determining the efficiency of fences as a windbreak, is typically studied via scaled wind tunnel experiments and numerical simulations. However, the scale problem in wind tunnels or numerical models is rarely researched. In this study, we perform a numerical comparison between a scaled wind-fence experimental model and an actual-sized fence via computational fluid dynamics simulations. The results show that although the general field pattern can be captured in a reduced-scale wind tunnel or numerical model, several flow characteristics near obstacles are not proportional to the size of the model and thus cannot be extrapolated directly. For example, the small vortex behind a low-porosity fence with a scale of 1:50 is approximately 4 times larger than that behind a full-scale fence.

Octopus visual system: a functional MRI model for detecting neuronal electric currents without a blood-oxygen-level-dependent confound.

PURPOSE: Despite the efforts that have been devoted to detecting the transient magnetic fields generated by neuronal firing, the conclusion that a functionally relevant signal can be measured with MRI is still controversial. For human studies of neuronal current MRI (nc-MRI), the blood-oxygen-level-dependent (BOLD) effect remains an irresolvable confound. For tissue studies where hemoglobin is removed, natural sensory stimulation is not possible. This study investigates the feasibility of detecting a physiologically induced nc-MRI signal in vivo in a BOLD-free environment. METHODS: The cephalopod mollusc Octopus bimaculoides has vertebrate-like eyes, large optic lobes (OLs), and blood that does not contain hemoglobin. Visually evoked potentials were measured in the octopus retina and OL by electroretinogram and local field potential. nc-MRI scans were conducted at 9.4 Tesla to capture these activities. RESULTS: Electrophysiological recording detected strong responses in the retina and OL in vivo; however, nc-MRI failed to demonstrate any statistically significant signal change with a detection threshold of 0.2° for phase and 0.2% for magnitude. Experiments in a dissected eye-OL preparation yielded similar results. CONCLUSION: These findings in a large hemoglobin-free nervous system suggest that sensory evoked neuronal magnetic fields are too weak for direct detection with current MRI technology.

Write to read: the brain's universal reading and writing network.

Do differences in writing systems translate into differences in the brain's reading network? Or is this network universal, relatively impervious to variation in writing systems? A new study adds intriguing evidence to these questions by showing that reading handwritten words activates a pre-motor area across writing systems.

Effects of culture on musical pitch perception.

The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture-to-perception influences.

Electrophysiological evidence for the left-lateralized effect of language on preattentive categorical perception of color.

Previous studies have shown that the effect of language on categorical perception of color is stronger when stimuli are presented in the right visual field than in the left. To examine whether this lateralized effect occurs preattentively at an early stage of processing, we monitored the visual mismatch negativity, which is a component of the event-related potential of the brain to an unfamiliar stimulus among a temporally presented series of stimuli. In the oddball paradigm we used, the deviant stimuli were unrelated to the explicit task. A significant interaction between color-pair type (within-category vs. between-category) and visual field (left vs. right) was found. The amplitude of the visual mismatch negativity component evoked by the within-category deviant was significantly smaller than that evoked by the between-category deviant when displayed in the right visual field, but no such difference was observed for the left visual field. This result constitutes electroencephalographic evidence that the lateralized Whorf effect per se occurs out of awareness and at an early stage of processing.

Lateralization of the arcuate fasciculus and its differential correlation with reading ability between young learners and experienced readers: a diffusion tensor tractography study in a Chinese cohort.

As Chinese reading engages a different neural network from alphabetic language reading, we investigate whether leftward lateralization of the arcuate fasciculus (AF), as observed in the Western population, is also present in the Chinese population and if it does, whether it is associated with better reading ability. Diffusion tensor tractography analysis on 75 Chinese subjects of three age groups (first graders, fourth graders, and college students) showed that 70-83% of them had leftward lateralization of the AF. The pattern of lateralization did not differ significantly among the three groups, suggesting that lateralization of the AF is formed at an early age and before one enters first grade. Among the first graders, who had just started to learn to read, subjects with strongly leftward lateralized AF scored significantly higher than those with other defined lateralization patterns in Chinese (P = 0.001) and English (P = 0.036) reading tasks. This association was not observed among the fourth graders and college students who were experienced Chinese readers. Among the fourth graders, females were found to obtain significantly higher Chinese (P = 0.033) and English reading scores than males (P = 0.002). Our study suggests a differential effect of leftward lateralization of the AF on reading ability at different stages of reading development in the Chinese population.

Improvement of spectral density-based activation detection of event-related fMRI data.

For event-related data obtained from an experimental paradigm with a periodic design, spectral density at the fundamental frequency of the paradigm has been used as a template-free activation detection measure. In this article, we build and expand upon this detection measure to create an improved, integrated measure. Such an integrated measure linearly combines information contained in the spectral densities at the fundamental frequency as well as the harmonics of the paradigm and in a spatial correlation function characterizing the degree of co-activation among neighboring voxels. Several figures of merit are described and used to find appropriate values for the coefficients in the linear combination. Using receiver-operating characteristic analysis on simulated functional magnetic resonance imaging (fMRI) data sets, we quantify and validate the improved performance of the integrated measure over the spectral density measure based on the fundamental frequency as well as over some other popular template-free data analysis methods. We then demonstrate the application of the new method on an experimental fMRI data set. Finally, several extensions to this work are suggested.

Time-dependent correlation of cerebral blood flow with oxygen metabolism in activated human visual cortex as measured by fMRI.

The aim of this study was to investigate the relationship between relative cerebral blood flow (delta CBF) and relative cerebral metabolic rate of oxygen (delta CMRO(2)) during continuous visual stimulation (21 min at 8 Hz) with fMRI biophysical models by simultaneously measuring of BOLD, CBF and CBV fMRI signals. The delta CMRO(2) was determined by both a newly calibrated single-compartment model (SCM) and a multi-compartment model (MCM) and was in agreement between these two models (P>0.5). The duration-varying delta CBF and delta CMRO(2) showed a negative correlation with time (r=-0.97, P<0.001); i.e., delta CBF declines while delta CMRO(2) increases during continuous stimulation. This study also illustrated that without properly calibrating the critical parameters employed in the SCM, an incorrect and even an opposite appearance of the flow-metabolism relationship during prolonged visual stimulation (positively linear coupling) can result. The time-dependent negative correlation between flow and metabolism demonstrated in this fMRI study is consistent with a previous PET observation and further supports the view that the increase in CBF is driven by factors other than oxygen demand and the energy demands will eventually require increased aerobic metabolism as stimulation continues.