Native Space Research Articles

The effect of phonetic production training with visual feedback on the perception and production of foreign speech sounds.

Second-language learners often experience major difficulties in producing non-native speech sounds. This paper introduces a training method that uses a real-time analysis of the acoustic properties of vowels produced by non-native speakers to provide them with immediate, trial-by-trial visual feedback about their articulation alongside that of the same vowels produced by native speakers. The Mahalanobis acoustic distance between non-native productions and target native acoustic spaces was used to assess L2 production accuracy. The experiment shows that 1 h of training per vowel improves the production of four non-native Danish vowels: the learners' productions were closer to the corresponding Danish target vowels after training. The production performance of a control group remained unchanged. Comparisons of pre- and post-training vowel discrimination performance in the experimental group showed improvements in perception. Correlational analyses of training-related changes in production and perception revealed no relationship. These results suggest, first, that this training method is effective in improving non-native vowel production. Second, training purely on production improves perception. Finally, it appears that improvements in production and perception do not systematically progress at equal rates within individuals.

Comparative assessment of SUVR methods and reference regions in amyloid PET studies

INTRODUCTION  We compare results of standard uptake value ratio (SUVR) analyses of Alzheimer’s Disease Neuroimaging Initiative (ADNI) florbetapir PET scans using a native space compared to SPM template methods and a variety of possible SUVR reference regions.  The objective is to find a method with highest longitudinal effect size to allow a sufficiently powered clinical trial efficacy measure using the smallest number of subjects.

Selective Vulnerability of Cortical Border Zone to Microembolic Infarct.

Endovascular procedures, including atrial fibrillation transcatheter ablation, may cause microembolization of brain arteries. Microemboli often cause small sized and clinically silent cerebral ischemias (SCI). These lesions are clearly visible on early postoperative magnetic resonance diffusion-weighted images. We analyzed SCI distribution in a population of patients submitted to atrial fibrillation transcatheter ablation. Seventy-eight of 927 consecutive patients submitted to atrial fibrillation transcatheter ablation were found positive for acute SCI on a postoperative magnetic resonance. SCI were identified and marked, and their coordinates were transformed from native space into the International Consortium for Brain Mapping/Montreal Neurological Institute space. We then computed the voxel-wise probability distribution map of the SCI using the activation likelihood estimation approach. SCI were more commonly found in the cortex. In supratentorial regions, SCI selectively involved cortical border zone between anterior, middle, and posterior cerebral arteries; in infratentorial regions, distal territory of posteroinferior cerebellar artery. Possible explanations include selective embolization, linked to the vascular anatomy of pial arteries supplying those territories, reduced clearance of emboli in a relatively hypoperfused zone, or a combination of both. This particular distribution of lesions has been reported in both animal models and in patients with microemboli of different sources. A selective vulnerability of cortical border zone to microemboli occurring during atrial fibrillation transcatheter ablation was observed. We hypothesize that such selectivity may apply to microemboli of different sources.

Automatic whole brain tract-based analysis using predefined tracts in a diffusion spectrum imaging template and an accurate registration strategy.

Automated tract-based analysis of diffusion MRI is an important tool for investigating tract integrity of the cerebral white matter. Current template-based automatic analyses still lack a comprehensive list of tract atlas and an accurate registration method. In this study, tract-based automatic analysis (TBAA) was developed to meet the demands. Seventy-six major white matter tracts were reconstructed on a high-quality diffusion spectrum imaging (DSI) template, and an advanced two-step registration strategy was proposed by incorporating anatomical information of the gray matter from T1-weighted images in addition to microstructural information of the white matter from diffusion-weighted images. The automatic analysis was achieved by establishing a transformation between the DSI template and DSI dataset of the subject derived from the registration strategy. The tract coordinates in the template were transformed to native space in the individual's DSI dataset, and the microstructural properties of major tract bundles were sampled stepwise along the tract coordinates of the subject's DSI dataset. In a validation study of eight well-known tracts, our results showed that TBAA had high geometric agreement with manual tracts in both deep and superficial parts but significantly smaller measurement variability than manual method in functional difference. Additionally, the feasibility of the method was demonstrated by showing tracts with altered microstructural properties in patients with schizophrenia. Fifteen major tract bundles were found to have significant differences after controlling the family-wise error rate. In conclusion, the proposed TBAA method is potentially useful in brain-wise investigations of white matter tracts, particularly for a large cohort study.

Multiscale interpolation on the sphere: Convergence rate and inverse theorem

In this paper we study the convergence rate and inverse theorem for spherical multiscale interpolation in Lp and Sobolev norms. The multiscale interpolation is constructed using a sequence of scaled, compactly supported radial basis functions restricted to the unit sphere Sn. For the interpolation scheme the problem called “native space barrier” is considered. In addition, a Bernstein type inequality is established to derive an inverse theorem for the multiscale interpolation, and some numerical experiments to illustrate the theoretical results are given.

Spherical scattered data quasi-interpolation by Gaussian radial basis function

Since the spherical Gaussian radial function is strictly positive definite, the authors use the linear combinations of translations of the Gaussian kernel to interpolate the scattered data on spheres in this article. Seeing that target functions are usually outside the native spaces, and that one has to solve a large scaled system of linear equations to obtain combinatorial coefficients of interpolant functions, the authors first probe into some problems about interpolation with Gaussian radial functions. Then they construct quasi-interpolation operators by Gaussian radial function, and get the degrees of approximation. Moreover, they show the error relations between quasi-interpolation and interpolation when they have the same basis functions. Finally, the authors discuss the construction and approximation of the quasi-interpolant with a local support function.

Structural development of human brain white matter from mid-fetal to perinatal stage.

The structures of developing human brain white matter (WM) tracts can be effectively quantified by DTI-derived metrics, including fractional anisotropy (FA), mean, axial and radial diffusivity (MD, AD and RD). However, dynamics of WM microstructure during very early developmental period from mid-fetal to perinatal stage is unknown. It is difficult to accurately measure microstructural properties of these WM tracts due to severe contamination from cerebrospinal fluid (CSF). In this study, high resolution DTI of fetal brains at mid-fetal stage (20 weeks of gestation or 20wg), 19 brains in the middle of 3rd trimester (35wg) and 17 brains around term (40wg) were acquired. We established first population-averaged DTI templates at these three time points and extracted WM skeleton. 16 major WM tracts in limbic, projection, commissural and association tract groups were traced with DTI tractography in native space. The WM skeleton in the template space was inversely transformed back to the native space for measuring core WM microstructures of each individual tract. Continuous microstructural enhancement and volumetric increase of WM tracts were found from 20wg to 40wg. The microstructural enhancement from FA measurement is decelerated in late 3rd trimester compared to mid-fetal to middle 3rd trimester, while volumetric increase of prefrontal WM tracts is accelerated. The microstructural enhancement from 35wg to 40wg is heterogeneous among different tract groups with microstructures of association tracts undergoing most dramatic change. Besides decreases of RD indicating active myelination, the decrease of AD for most WM tracts during late 3rd trimester suggests axonal packing process.

Changes in fMRI Hypothalamic Activity Via Intrinsic Oscillations After Intake of Regular Soda, Diet Soda or Water During a Meal

The aim of this study was to examine hypothalamic changes after intake of different beverages at normal levels of consumption.A total of 63 healthy, non‐diabetic, normotensive subjects with BMI 21‐29.9 kg/m2, between the ages of 20‐50 years took part in an fMRI scanning session. The protocol consisted of six runs of resting‐state‐fMRI. During the first two runs subjects were in the fasting state. Subsequently they ate a standardized meal for 30 minutes outside the scanner that included either a regular soda, a diet soda, or water, based on random allocation (n=21 for each group). After the meal, subjects were scanned four additional runs. For data analysis, standard image preprocessing was performed using FSL software. We used fractional amplitude of low‐frequency fluctuation (fALFF), a validated method that allows the detection of the regional intensity of spontaneous low fluctuations (0.01–0.08 Hz) in fMRI BOLD signal. Voxelwise fALFF maps were calculated for each participant in native space, and then transformed into the MNI152 standard brain space. Before statistical analyses, each individual fALFF map was Z‐transformed. A seed of 3 mm of hypothalamus based on a previous study was used to extract the Z values from these fALFF maps for group‐level parametric analyses. We modeled the data using ANOVA with group (regular soda, diet soda, water), and condition (fast, fed) as factors.There was no effect of metabolic condition (F=1.99, p=0.16) or group (F=0.77, p=0.46). The interaction group x condition was also not significant (F=0.57, p=0.56). These results suggest that the previously identified differences may not apply to the case of SSBs under conditions that are more representative of normal daily intake levels and patterns.

SMaRT: A novel framework for addressing range queries over nonlinear trajectories

A spatiotemporal database is a database that manages both space and time information. Common examples include tracking of moving objects, intelligent transportation systems, cellular communications and meteorology monitoring. A spatiotemporal query determines the objects included in a region at a specified period of time between two date-time instants referred as time window. In the context of this work, we present SMaRT: A novel Spatiotemporal Mysql ReTrieval framework, based on MySQL and PostgreSQL database management system. Moreover, we propose a demo user interface that implements all of its capabilities, in order to help user determine the most efficient spatiotemporal query method on user-defined 2D trajectories. To our knowledge, we are the first to study and compare methods of addressing range queries on nonlinear moving object trajectories, that are represented both in dual and native dimensional space. In particular, it is the first time a theoretically efficient dual approach was implemented for nonlinear trajectories and incorporated into a well-known open-source RDBMS. An experimental evaluation is included that shows the performance and efficiency of our approach.

Robust volume assessment of brain tissues for 3-dimensional fourier transformation MRI via a novel multispectral technique.

A new TRIO algorithm method integrating three different algorithms is proposed to perform brain MRI segmentation in the native coordinate space, with no need of transformation to a standard coordinate space or the probability maps for segmentation. The method is a simple voxel-based algorithm, derived from multispectral remote sensing techniques, and only requires minimal operator input to depict GM, WM, and CSF tissue clusters to complete classification of a 3D high-resolution multislice-multispectral MRI data. Results showed very high accuracy and reproducibility in classification of GM, WM, and CSF in multislice-multispectral synthetic MRI data. The similarity indexes, expressing overlap between classification results and the ground truth, were 0.951, 0.962, and 0.956 for GM, WM, and CSF classifications in the image data with 3% noise level and 0% non-uniformity intensity. The method particularly allows for classification of CSF with 0.994, 0.961 and 0.996 of accuracy, sensitivity and specificity in images data with 3% noise level and 0% non-uniformity intensity, which had seldom performed well in previous studies. As for clinical MRI data, the quantitative data of brain tissue volumes aligned closely with the brain morphometrics in three different study groups of young adults, elderly volunteers, and dementia patients. The results also showed very low rates of the intra- and extra-operator variability in measurements of the absolute volumes and volume fractions of cerebral GM, WM, and CSF in three different study groups. The mean coefficients of variation of GM, WM, and CSF volume measurements were in the range of 0.03% to 0.30% of intra-operator measurements and 0.06% to 0.45% of inter-operator measurements. In conclusion, the TRIO algorithm exhibits a remarkable ability in robust classification of multislice-multispectral brain MR images, which would be potentially applicable for clinical brain volumetric analysis and explicitly promising in cross-sectional and longitudinal studies of different subject groups.

Disrupted fornix integrity in children with chromosome 22q11.2 deletion syndrome

The fornix is the primary subcortical output fiber system of the hippocampal formation. In children with 22q11.2 deletion syndrome (22q11.2DS), hippocampal volume reduction has been commonly reported, but few studies as yet have evaluated the integrity of the fornix. Therefore, we investigated the fornix of 45 school-aged children with 22q11.2DS and 38 matched typically developing (TD) children. Probabilistic diffusion tensor imaging (DTI) tractography was used to reconstruct the body of the fornix in each child׳s brain native space. Compared with children, significantly lower fractional anisotropy (FA) and higher radial diffusivity (RD) was observed bilaterally in the body of the fornix in children with 22q11.2DS. Irregularities were especially prominent in the posterior aspect of the fornix where it emerges from the hippocampus. Smaller volumes of the hippocampal formations were also found in the 22q11.2DS group. The reduced hippocampal volumes were correlated with lower fornix FA and higher fornix RD in the right hemisphere. Our findings provide neuroanatomical evidence of disrupted hippocampal connectivity in children with 22q11.2DS, which may help to further understand the biological basis of spatial impairments, affective regulation, and other factors related to the ultra-high risk for schizophrenia in this population.

The impact of normalization and segmentation on resting-state brain networks.

Graph theory has recently received a lot of attention from the neuroscience community as a method to represent and characterize brain networks. Still, there is a lack of a gold standard for the methods that should be employed for the preprocessing of the data and the construction of the networks, as well as a lack of knowledge on how different methodologies can affect the metrics reported. The authors used graph theory analysis applied to resting-state functional magnetic resonance imaging to investigate the influence of different node-defining strategies and the effect of normalizing the functional acquisition on several commonly reported metrics used to characterize brain networks. The nodes of the network were defined using either the individual FreeSurfer segmentation of each subject or the FreeSurfer segmented Montreal National Institute (MNI) 152 template, using the Destrieux and subcortical atlas. The functional acquisition was either kept on the functional native space or normalized into MNI standard space. The comparisons were done at three levels: on the connections, on the edge properties, and on the network properties levels. The results reveal that different registration and brain parcellation strategies have a strong impact on all the levels of analysis, possibly favoring the use of individual segmentation strategies and conservative registration approaches. In conclusion, several technical aspects must be considered so that graph theoretical analysis of connectivity MRI data can provide a framework to understand brain pathologies.

Hierarchical Multi-modal Image Registration by Learning Common Feature Representations.

Mutual information (MI) has been widely used for registering images with different modalities. Since most inter-modality registration methods simply estimate deformations in a local scale, but optimizing MI from the entire image, the estimated deformations for certain structures could be dominated by the surrounding unrelated structures. Also, since there often exist multiple structures in each image, the intensity correlation between two images could be complex and highly nonlinear, which makes global MI unable to precisely guide local image deformation. To solve these issues, we propose a hierarchical inter-modality registration method by robust feature matching. Specifically, we first select a small set of key points at salient image locations to drive the entire image registration. Since the original image features computed from different modalities are often difficult for direct comparison, we propose to learn their common feature representations by projecting them from their native feature spaces to a common space, where the correlations between corresponding features are maximized. Due to the large heterogeneity between two high-dimension feature distributions, we employ Kernel CCA (Canonical Correlation Analysis) to reveal such non-linear feature mappings. Then, our registration method can take advantage of the learned common features to reliably establish correspondences for key points from different modality images by robust feature matching. As more and more key points take part in the registration, our hierarchical feature-based image registration method can efficiently estimate the deformation pathway between two inter-modality images in a global to local manner. We have applied our proposed registration method to prostate CT and MR images, as well as the infant MR brain images in the first year of life. Experimental results show that our method can achieve more accurate registration results, compared to other state-of-the-art image registration methods.

Mid-Space-Independent Symmetric Data Term for Pairwise Deformable Image Registration.

Aligning a pair of images in a mid-space is a common approach to ensuring that deformable image registration is symmetric - that it does not depend on the arbitrary ordering of the input images. The results are, however, generally dependent on the choice of the mid-space. In particular, the set of possible solutions is typically affected by the constraints that are enforced on the two transformations (that deform the two images), which are to prevent the mid-space from drifting too far from the native image spaces. The use of an implicit atlas has been proposed to define the mid-space for pairwise registration. In this work, we show that by aligning the atlas to each image in the native image space, implicit-atlas-based pairwise registration can be made independent of the mid-space, thereby eliminating the need for anti-drift constraints. We derive a new symmetric cost function that only depends on a single transformation morphing one image to the other, and validate it through diffeomorphic registration experiments on brain magnetic resonance images.

Native Sovereignty and the Archive: Samson Occom and Digital Humanities

AbstractThis essay describes The Occom Circle, a scholarly digital edition of documents held at Dartmouth College by and about Samson Occom (1723–92), a Mohegan Indian, Presbyterian minister, political activist, and the foremost Native writer in eighteenth-century North America. In its content and method, The Occom Circle puts Native space and activities closer to the center of our early history. Framing this digital humanities project with the themes of Native sovereignty, the politics of archives, and the affordances of the digital, the essay considers how scholars can maintain a feminist and post-/non-colonial approach to the uses of technology to advance what scholars have labeled “ethnic archives” and public-oriented archival projects in the digital age. It argues that Native intellectual sovereignty is processional, that archives can reveal and preserve the often-ephemeral affective structures of colonial relations, and that digital technology can offer methodologies that embrace the evolving nature of knowledge.

Native Sovereignty and the Archive: Samson Occom and Digital Humanities

Abstract This essay describes The Occom Circle, a scholarly digital edition of documents held at Dartmouth College by and about Samson Occom (1723–92), a Mohegan Indian, Presbyterian minister, political activist, and the foremost Native writer in eighteenth-century North America. In its content and method, The Occom Circle puts Native space and activities closer to the center of our early history. Framing this digital humanities project with the themes of Native sovereignty, the politics of archives, and the affordances of the digital, the essay considers how scholars can maintain a feminist and post-/non-colonial approach to the uses of technology to advance what scholars have labeled “ethnic archives” and public-oriented archival projects in the digital age. It argues that Native intellectual sovereignty is processional, that archives can reveal and preserve the often-ephemeral affective structures of colonial relations, and that digital technology can offer methodologies that embrace the evolving nature of knowledge.

Boundaries of Person, Boundaries of Place: Wilderness, "Indians" and the Mapping of Canada's Northwest Interior, 1857

This essay identifies the creative and often divergent constructions of place and race in one document, the proceedings from a Parliamentary Select Committee in 1857, which empowered officials three thousand miles across the Atlantic to make varying claims to a vast and diverse expanse of Aboriginal lands and peoples in Canada. I apply theory from existing scholarship about the “mutually imbricated” nature of place and race in the making settler-colonial worlds to find how six hundred pages of testimony from white men with only marginal experiences on the land itself legitimized the dispossession and marginalization the original inhabitants of those territories.[1] I focus mostly on the lands between the Great Lakes and the Rocky Mountains, the bulk of which were fashioned in distant, imperial imaginations as “wilderness,” unfit for or in need of settler “civilization.” In conjunction with wilderness discourses, speakers defined the Indianness of the northwest interior. Mostly Plains peoples, the indigenous groups discussed in this document were universally painted as one with their environment: wild and uncivilized. They were, according to the commission, incapable of governing themselves responsibly, and were, worst of all, the sure victims of the “onslaught of colonization,” should they not become in some way transformed.The document provides some fascinating divergences in the mindsets of different colonial powers: the HBC, British settlers in Canada, and humanitarians. These divergences reflect how, as Bronwen Douglas suggests, “within colonial regimes and contexts […] the efflorescence of racially charged utterances and practices betrays an astonishing variety, fluidity and internal contradiction.”[2]During the sessions of testimony and debate for this enquiry, constructions of land and Indianness in the northwest interior came together to justify variant and often contradictory solutions to the “problems” colonizers identified in the “unsettled” territory. All discourses that produced, and produced by, colonialism could be harnessed to dispossess Aboriginal peoples; the means and justifications for doing so in this document varied.[3][1] Tracey Banivanua-Mar and Penelope Edmonds, eds., Making Settler Colonial Space: Perspectives on Race, Place and Identity (New York: Palgrave MacMillan, 2010), 3.[2] Douglas, “Race,” 245.[3] Cole Harris, Making Native Space: Colonialism, Resistance, and Reserves in British Columbia (Vancouver: UBC Press, 2002), 48.

On the effects of L2 perception and of individual differences in L1 production on L2 pronunciation.

The speech of late second language (L2) learners is generally marked by an accent. The dominant theoretical perspective attributes accents to deficient L2 perception arising from a transfer of L1 phonology, which is thought to influence L2 perception and production. In this study we evaluate the explanatory role of L2 perception in L2 production and explore alternative explanations arising from the L1 phonological system, such as for example, the role of L1 production. Specifically we examine the role of an individual’s L1 productions in the production of L2 vowel contrasts. Fourteen Spanish adolescents studying French at school were assessed on their perception and production of the mid-close/mid-open contrasts, /ø-œ/ and /e-ε/, which are, respectively, acoustically distinct from Spanish sounds, or similar to them. The participants’ native productions were explored to assess (1) the variability in the production of native vowels (i.e., the compactness of vowel categories in F1/F2 acoustic space), and (2) the position of the vowels in the acoustic space. The results revealed that although poorly perceived contrasts were generally produced poorly, there was no correlation between individual performance in perception and production, and no effect of L2 perception on L2 production in mixed-effects regression analyses. This result is consistent with a growing body of psycholinguistic and neuroimaging research that suggest partial dissociations between L2 perception and production. In contrast, individual differences in the compactness and position of native vowels predicted L2 production accuracy. These results point to existence of surface transfer of individual L1 phonetic realizations to L2 space and demonstrate that pre-existing features of the native space in production partly determine how new sounds can be accommodated in that space.

Settler-colonialist management of entrances to the native urban space in Palestine

In the pursuit of ethnically based settlements, Israel continues to illegally confiscate Palestinian land and populate it with settlers. A system of spatial control was devised to maintain the pace of settler spatial expansion. It is an ad hoc and elastic system that is continuously revised and upgraded, while new elements are added to it. This paper studies the entrance/exit element that was added to the control infrastructure after the second Intifada. The entrance/exit construct is an added detail in a spatial order that seeks to process the ‘entrance into’ and ‘exit from’ Palestinian urban areas, enclaves or reservations. This order aims to constrain the Palestinians into an increasingly shrinking space within the accumulative settler-colonialist process of land expropriation. Furthermore, this structure provides reference nodes that offer a perspective from above over the native space and movement. Consequently, these elements should be seen as physical structures that modulate both humans and space.

Territorial Trap

Most attempts to integrate “small,” or “minor,” or “third-world” literatures into a larger whole tend to be inadequate, deductive, and reductionist. Small literatures and their writers may crave recognition and attention, but they are not exactly helped if approached with a set of newly created stereotypes and dubious generalizations, which equate them with the geopolitical situation of their respective nations. This article focuses on Casanova’s The World Republic of Letters as an instance of this attitude towards small literatures. The article uses the example of Danilo Kiš, who figures prominently in Casanova’s book, and argues that his position within his native literary space and the place occupied by this space within world literature are misrepresented in The World Republic of Letters. This misrepresentation is not accidental: It necessarily follows from Casanova’s double mapping of this space, which is strongly influenced by geopolitical imagination and popular cultural geography. As long as the international literary space is imagined as overlapping with the space of great consecrating nations, comprising both their national as well as international writers, with the addition of international writers from the periphery “annexed” to them, the world literary map will only reproduce the (geo)political map of the world. The task of constructing a conceptual framework that will do justice to small or third-world literatures and their writers cannot be achieved so long as it is influenced by geopolitical imagination and popular cultural geography, and divides the world literature into the “first-world” and the rest.