Rapid development of perceptual gaze control in hearing native signing Infants and children.

Children's gaze behavior reflects emergent linguistic knowledge and real-time language processing of speech, but little is known about naturalistic gaze behaviors while watching signed narratives. Measuring gaze patterns in signing children could uncover how they master perceptual gaze control during a time of active language learning. Gaze patterns were recorded using a Tobii X120 eye tracker, in 31 non-signing and 30 signing hearing infants (5-14 months) and children (2-8 years) as they watched signed narratives on video. Intelligibility of the signed narratives was manipulated by presenting them naturally and in video-reversed ("low intelligibility") conditions. This video manipulation was used because it distorts semantic content, while preserving most surface phonological features. We examined where participants looked, using linear mixed models with Language Group (non-signing vs. signing) and Video Condition (Forward vs. Reversed), controlling for trial order. Non-signing infants and children showed a preference to look at the face as well as areas below the face, possibly because their gaze was drawn to the moving articulators in signing space. Native signing infants and children demonstrated resilient, face-focused gaze behavior. Moreover, their gaze behavior was unchanged for video-reversed signed narratives, similar to what was seen for adult native signers, possibly because they already have efficient highly focused gaze behavior. The present study demonstrates that human perceptual gaze control is sensitive to visual language experience over the first year of life and emerges early, by 6 months of age. Results have implications for the critical importance of early visual language exposure for deaf infants. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=2ahWUluFAAg.

Effects of Video Reversal on Gaze Patterns during Signed Narrative Comprehension.

Language knowledge, age of acquisition (AoA), and stimulus intelligibility all affect gaze behavior for reading print, but it is unknown how these factors affect "sign-watching" among signers. This study investigated how these factors affect gaze behavior during sign language comprehension in 52 adult signers who acquired American Sign Language (ASL) at different ages. We examined gaze patterns and story comprehension in four subject groups who differ in hearing status and when they learned ASL (i.e. Deaf Early, Deaf Late, Hearing Late, and Hearing Novice). Participants watched signed stories in normal (high intelligibility) and video-reversed (low intelligibility) conditions. This video manipulation was used because it distorts word order and thus disrupts the syntax and semantic content of narratives, while preserving most surface phonological features of individual signs. Video reversal decreased story comprehension accuracy, and this effect was greater for those who learned ASL later in life. Reversal also was associated with more dispersed gaze behavior. Although each subject group had unique gaze patterns, the effect of video reversal on gaze measures was similar across all groups. Among fluent signers, gaze behavior was not correlated with AoA, suggesting that "efficient" sign watching can be quickly learnt even among signers exposed to signed language later in life.

Exploring Infant Sensitivity to Visual Language using Eye Tracking and the Preferential Looking Paradigm.

We discuss the use of the preferential looking paradigm in eye tracking studies in order to study how infants develop, understand, and attend to the world around them. Eye tracking is a safe and non-invasive way to collect gaze data from infants, and the preferential looking paradigm is simple to design and only requires the infant to be attending to the screen. By simultaneously showing two visual stimuli that differ in one dimension, we can assess whether infants show different looking behavior for either stimulus, thus demonstrating sensitivity to that difference. The challenges in such experimental approaches are that experiments must be kept brief (no more than 10 min) and be carefully controlled such that the two stimuli differ in only one way. The interpretation of null results must also be carefully considered. In this paper, we illustrate a successful example of an infant eye tracking study with a preferential looking paradigm to discover that 6-month-olds are sensitive to linguistic cues in a signed language despite having no prior exposure to signed language, suggesting that infants possess intrinsic or innate sensitivities to these cues.

Visual Sonority Modulates Infants' Attraction to Sign Language.

The infant brain may be predisposed to identify perceptually salient cues that are common to both signed and spoken languages. Recent theory based on spoken languages has advanced sonority as one of these potential language acquisition cues. Using a preferential looking paradigm with an infrared eye tracker, we explored visual attention of hearing 6- and 12-month-olds with no sign language experience as they watched fingerspelling stimuli that either conformed to high sonority (well-formed) or low sonority (ill-formed) values, which are relevant to syllabic structure in signed language. Younger babies showed highly significant looking preferences for well-formed, high sonority fingerspelling, while older babies showed no preference for either fingerspelling variant, despite showing a strong preference in a control condition. The present findings suggest babies possess a sensitivity to specific sonority-based contrastive cues at the core of human language structure that is subject to perceptual narrowing, irrespective of language modality (visual or auditory), shedding new light on universals of early language learning.

Operationalization of Sign Language Phonological Similarity and its Effects on Lexical Access.

Cognitive mechanisms for sign language lexical access are fairly unknown. This study investigated whether phonological similarity facilitates lexical retrieval in sign languages using measures from a new lexical database for American Sign Language. Additionally, it aimed to determine which similarity metric best fits the present data in order to inform theories of how phonological similarity is constructed within the lexicon and to aid in the operationalization of phonological similarity in sign language. Sign repetition latencies and accuracy were obtained when native signers were asked to reproduce a sign displayed on a computer screen. Results indicated that, as predicted, phonological similarity facilitated repetition latencies and accuracy as long as there were no strict constraints on the type of sublexical features that overlapped. The data converged to suggest that one similarity measure, MaxD, defined as the overlap of any 4 sublexical features, likely best represents mechanisms of phonological similarity in the mental lexicon. Together, these data suggest that lexical access in sign language is facilitated by phonologically similar lexical representations in memory and the optimal operationalization is defined as liberal constraints on overlap of 4 out of 5 sublexical features-similar to the majority of extant definitions in the literature.

Fingerspelling as a Novel Gateway into Reading Fluency in Deaf Bilinguals.

Studies have shown that American Sign Language (ASL) fluency has a positive impact on deaf individuals' English reading, but the cognitive and cross-linguistic mechanisms permitting the mapping of a visual-manual language onto a sound-based language have yet to be elucidated. Fingerspelling, which represents English orthography with 26 distinct hand configurations, is an integral part of ASL and has been suggested to provide deaf bilinguals with important cross-linguistic links between sign language and orthography. Using a hierarchical multiple regression analysis, this study examined the relationship of age of ASL exposure, ASL fluency, and fingerspelling skill on reading fluency in deaf college-age bilinguals. After controlling for ASL fluency, fingerspelling skill significantly predicted reading fluency, revealing for the first-time that fingerspelling, above and beyond ASL skills, contributes to reading fluency in deaf bilinguals. We suggest that both fingerspelling--in the visual-manual modality--and reading--in the visual-orthographic modality--are mutually facilitating because they share common underlying cognitive capacities of word decoding accuracy and automaticity of word recognition. The findings provide support for the hypothesis that the development of English reading proficiency may be facilitated through strengthening of the relationship among fingerspelling, sign language, and orthographic decoding en route to reading mastery, and may also reveal optimal approaches for reading instruction for deaf and hard of hearing children.

Direct laser-writing of ferroelectric single-crystal waveguide architectures in glass for 3D integrated optics.

Direct three-dimensional laser writing of amorphous waveguides inside glass has been studied intensely as an attractive route for fabricating photonic integrated circuits. However, achieving essential nonlinear-optic functionality in such devices will also require the ability to create high-quality single-crystal waveguides. Femtosecond laser irradiation is capable of crystallizing glass in 3D, but producing optical-quality single-crystal structures suitable for waveguiding poses unique challenges that are unprecedented in the field of crystal growth. In this work, we use a high angular-resolution electron diffraction method to obtain the first conclusive confirmation that uniform single crystals can be grown inside glass by femtosecond laser writing under optimized conditions. We confirm waveguiding capability and present the first quantitative measurement of power transmission through a laser-written crystal-in-glass waveguide, yielding loss of 2.64 dB/cm at 1530 nm. We demonstrate uniformity of the crystal cross-section down the length of the waveguide and quantify its birefringence. Finally, as a proof-of-concept for patterning more complex device geometries, we demonstrate the use of dynamic phase modulation to grow symmetric crystal junctions with single-pass writing.

Right prefrontal and ventral striatum interactions underlying impulsive choice and impulsive responding.

Although a multifaceted concept, many forms of impulsivity may originate from interactions between prefrontally-mediated cognitive control mechanisms and limbic, reward or incentive salience approach processes. We describe a novel task that combines reward and control processes to probe this putative interaction. The task involves elements of the monetary incentive delay task (Knutson et al., [2000]: Neuroimage 12:20-27) and the Go/No-Go task (Garavan et al., [1999]: Neuroimage 17:1820-1829) and requires human subjects to make fast responses to targets for financial reward but to occasionally inhibit responding when a NoGo signal rather than a target is presented. In elucidating the dynamic between reward anticipation and control we observed that successful inhibitions on monetary trials, relative to unsuccessful inhibitions, were associated, during the anticipation phase, with increased activation in the right inferior frontal gyrus (rIFG), decreased activity in the ventral striatum (VS), and altered functional connectivity between the two. Notably, this rIFG area had a small overlap but was largely distinct from an adjacent rIFG region that was active for the subsequent motor response inhibitions. Combined, the results suggest a role for adjacent regions of the rIFG in impulsive choice and in impulsive responding and identify a functional coupling between the rIFG and the VS.

Putting the elephant back in the herd: elephant relative quantity judgments match those of other species.

The ability to discriminate between quantities has been observed in many species. Typically, when an animal is given a choice between two sets of food, accurate performance (i.e., choosing the larger amount) decreases as the ratio between two quantities increases. A recent study reported that elephants did not exhibit ratio effects, suggesting that elephants may process quantitative information in a qualitatively different way from all other nonhuman species that have been tested (Irie-Sugimoto et al. in Anim Cogn 12:193-199, 2009). However, the results of this study were confounded by several methodological issues. We tested two African elephants (Loxodonta africana) to more thoroughly investigate relative quantity judgment in this species. In contrast to the previous study, we found evidence of ratio effects for visible and nonvisible sequentially presented sets of food. Thus, elephants appear to represent and compare quantities in much the same way as other species, including humans when they are prevented from counting. Performance supports an accumulator model in which quantities are represented as analog magnitudes. Furthermore, we found no effect of absolute magnitude on performance, providing support against an object-file model explanation of quantity judgment.

Directionally controlled 3D ferroelectric single crystal growth in LaBGeO5 glass by femtosecond laser irradiation.

Laser-fabrication of complex, highly oriented three-dimensional ferroelectric single crystal architecture with straight lines and bends is demonstrated in lanthanum borogermanate model glass using a high repetition rate femtosecond laser. Scanning micro-Raman microscopy shows that the c-axis of the ferroelectric crystal is aligned with the writing direction even after bending. A gradual rather than an abrupt transition is observed for the changing lattice orientation through bends up to approximately 14 degrees. Thus the single crystal character of the line is preserved along the bend through lattice straining rather than formation of a grain boundary.

Effect of treatment for Chlamydia pneumoniae and Helicobacter pylori on markers of inflammation and cardiac events in patients with acute coronary syndromes: South Thames Trial of Antibiotics in Myocardial Infarction and Unstable Angina (STAMINA).

BACKGROUND: Infection with Helicobacter pylori and Chlamydia pneumoniae is associated with coronary heart disease. We conducted an intervention study using antibiotics against these bacteria in patients with acute coronary syndromes to determine whether antibiotics reduce inflammatory markers and adverse cardiac events. METHODS AND RESULTS: Patients (n=325) admitted with acute myocardial infarction or unstable angina (acute coronary syndromes) were randomized to receive a 1-week course of 1 of 3 treatment regimens: (1) placebo; (2) amoxicillin (500 mg twice daily), metronidazole (400 mg twice daily), and omeprazole (20 mg twice daily); or (3) azithromycin (500 mg once daily), metronidazole (400 mg twice daily), and omeprazole (20 mg twice daily). Serum fibrinogen, white cell count, and high-sensitivity C-reactive protein were measured at study entry and at 1, 3, and 12 months during follow-up. Cardiac death and readmission with acute coronary syndrome were considered clinical end points. Patients were followed for 1 year. C-reactive protein levels were reduced (P=0.03) in unstable angina patients receiving amoxicillin, and fibrinogen was reduced in both patient groups receiving antibiotics (P=0.06). There were 17 cardiac deaths and 71 readmissions with acute coronary syndrome. No difference in frequency or timing of end points was observed between the 2 antibiotic groups. At 12 weeks, there was a 36% reduction in all end points in patients receiving antibiotics compared with placebo (P=0.02). This reduction persisted during the 1-year follow-up. Neither C pneumoniae nor H pylori antibody status was significantly related to response to treatment. CONCLUSIONS: Antibiotic treatment significantly reduced adverse cardiac events in patients with acute coronary syndromes, but the effect was independent of H pylori or C pneumoniae seropositivity.