Magnetic resonance imaging of the brain and vocal tract:Applications to the study of speech production and language learning

The human vocal system is highly plastic, allowing for the flexible expression of language, mood and intentions. However, this plasticity is not stable throughout the life span, and it is well documented that adult learners encounter greater difficulty than children in acquiring the sounds of foreign languages. Researchers have used magnetic resonance imaging (MRI) to interrogate the neural substrates of vocal imitation and learning, and the correlates of individual differences in phonetic “talent”. In parallel, a growing body of work using MR technology to directly image the vocal tract in real time during speech has offered primarily descriptive accounts of phonetic variation within and across languages. In this paper, we review the contribution of neural MRI to our understanding of vocal learning, and give an overview of vocal tract imaging and its potential to inform the field. We propose methods by which our understanding of speech production and learning could be advanced through the combined measurement of articulation and brain activity using MRI – specifically, we describe a novel paradigm, developed in our laboratory, that uses both MRI techniques to for the first time map directly between neural, articulatory and acoustic data in the investigation of vocalisation. This non-invasive, multimodal imaging method could be used to track central and peripheral correlates of spoken language learning, and speech recovery in clinical settings, as well as provide insights into potential sites for targeted neural interventions

Ages at menarche- and menopause-related genetic variants in relation to terminal duct lobular unit involution in normal breast tissue

PURPOSE: Reduced levels of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini per TDLU, have been associated with higher breast cancer risk. Younger age at menarche and older age at menopause have been previously related to lower levels of TDLU involution. To determine a possible genetic link, we examined whether single nucleotide polymorphisms (SNPs) previously established in genome-wide association studies (GWAS) for ages at menarche and menopause are associated with TDLU involution. METHODS: We conducted a pooled analysis of 862 women from two studies. H&E tissue sections were assessed for numbers of TDLUs and acini/TDLU. Poisson regression models were used to estimate associations of 36 menarche- and 21 menopause-SNPs with TDLU counts, acini counts/TDLU, and the product of these two measures, adjusting for age and study site. RESULTS: Fourteen percent of evaluated SNPs (8 SNPs) were associated with TDLU counts at p<0.05, suggesting an enrichment of associations with TDLU counts. However, only menopause-SNPs had >50% that were either significantly or nonsignficantly associated with TDLU measures in the directions consistent with their relationships shown in GWAS. Among 10 SNPs that were statistically significantly associated with at least one TDLU involution measure (p<0.05), seven SNPs (rs466639: RXRG; rs2243803: SLC14A2; rs2292573: GAB2; rs6438424: 3q13.32; rs7606918: METAP1D; rs11668344: TMEM150B; rs1635501: EXO1) were associated in the consistent directions. CONCLUSIONS: Our data suggest that the loci associated with ages at menarche and menopause may influence TDLU involution, suggesting some shared genetic mechanisms. However, larger studies are needed to confirm the results

Nature of Cardiac Rehabilitation Around the Globe

BackgroundCardiac rehabilitation (CR) is a clinically-effective but complex model of care. The purpose of this study was to characterize the nature of CR programs around the world, in relation to guideline recommendations, and compare this by World Health Organization (WHO) region.MethodsIn this cross-sectional study, a piloted survey was administered online to CR programs globally. Cardiac associations and local champions facilitated program identification. Quality (benchmark of ≥ 75% of programs in a given country meeting each of 20 indicators) was ranked. Results were compared by WHO region using generalized linear mixed models.Findings111/203 (54.7%) countries in the world offer CR; data were collected in 93 (83.8%; N = 1082 surveys, 32.1% program response rate). The most commonly-accepted indications were: myocardial infarction (n = 832, 97.4%), percutaneous coronary intervention (n = 820, 96.1%; 0.10), and coronary artery bypass surgery (n = 817, 95.8%). Most programs were led by physicians (n = 680; 69.1%). The most common CR providers (mean = 5.9 ± 2.8/program) were: nurses (n = 816, 88.1%; low in Africa, p

Cardiac Rehabilitation Availability and Density around the Globe

BackgroundDespite the epidemic of cardiovascular disease and the benefits of cardiac rehabilitation (CR), availability is known to be insufficient, although this is not quantified. This study ascertained CR availability, volumes and its drivers, and density.MethodsA survey was administered to CR programs globally. Cardiac associations and local champions facilitated program identification. Factors associated with volumes were assessed using generalized linear mixed models, and compared by World Health Organization region. Density (i.e. annual ischemic heart disease [IHD] incidence estimate from Global Burden of Disease study divided by national CR capacity) was computed.FindingsCR was available in 111/203 (54.7%) countries; data were collected in 93 (83.8% country response; N?=?1082 surveys, 32.1% program response rate). Availability by region ranged from 80.7% of countries in Europe, to 17.0% in Africa (p

Pulse Jet Mixing Tests With Noncohesive Solids

This report summarizes results from pulse jet mixing (PJM) tests with noncohesive solids in Newtonian liquid conducted during FY 2007 and 2008 to support the design of mixing systems for the Hanford Waste Treatment and Immobilization Plant (WTP). Tests were conducted at three geometric scales using noncohesive simulants. The test data were used to independently develop mixing models that can be used to predict full-scale WTP vessel performance and to rate current WTP mixing system designs against two specific performance requirements. One requirement is to ensure that all solids have been disturbed during the mixing action, which is important to release gas from the solids. The second requirement is to maintain a suspended solids concentration below 20 weight percent at the pump inlet. The models predict the height to which solids will be lifted by the PJM action, and the minimum velocity needed to ensure all solids have been lifted from the floor. From the cloud height estimate we can calculate the concentration of solids at the pump inlet. The velocity needed to lift the solids is slightly more demanding than "disturbing" the solids, and is used as a surrogate for this metric. We applied the models to assess WTP mixing vessel performance with respect to the two perform¬ance requirements. Each mixing vessel was evaluated against these two criteria for two defined waste conditions. One of the wastes was defined by design limits and one was derived from Hanford waste characterization reports. The assessment predicts that three vessel types will satisfy the design criteria for all conditions evaluated. Seven vessel types will not satisfy the performance criteria used for any of the conditions evaluated. The remaining three vessel types provide varying assessments when the different particle characteristics are evaluated. The assessment predicts that three vessel types will satisfy the design criteria for all conditions evaluated. Seven vessel types will not satisfy the performance criteria used for any of the conditions evaluated. The remaining three vessel types provide varying assessments when the different particle characteristics are evaluated. The HLP-022 vessel was also evaluated using 12 m/s pulse jet velocity with 6-in. nozzles, and this design also did not satisfy the criteria for all of the conditions evaluated

Perceptual and Memory Metacognition in Children

Confidence can be experienced for all kinds of decisions – evaluating the value of a piece of artwork, determining whether the lights are flickering, or remembering where we left our keys. These are fundamentally different kinds of decisions, but does that mean the confidence we feel is also fundamentally different for each one? Here, we test competing theories of domain-generality and domain-specificity in metacognitive ability by correlating individual differences in memory and perceptual confidence judgments in childhood. Children performed a recognition memory task and an area discrimination task followed by confidence judgments. Using 4 measures of metacognitive ability (indicated by higher confidence for accurate compared to inaccurate judgments: difference scores, meta-d’, MRatio, and HMeta-d’), we find no significant correlations between this ability in memory and perceptual tasks. These findings support an account of domain-specificity in children’s metacognitive abilities

Developing a sense of certainty

In a noisy world filled with confusion, humans need a toolkit of skills to help discern fact from fiction. In this dissertation, I explore one such tool and its development in childhood: metacognitive reasoning about confidence. In 7 studies, I investigate how children reason about the strength of subjective information, uncovering the properties of childhood metacognition and using its development as a tool to learn about metacognition more broadly. Fueling this research are two families of theoretical accounts: one which conceptualizes confidence as a direct readout of decision noise (Direct accounts), and one where confidence is a combination of information from multiple sources (Inferential accounts). These two accounts make divergent predictions about two properties of metacognition: (1) how tightly bound confidence is to the underlying decisions it evaluates, and (2) how broadly is confidence represented in the mind. I investigate these questions using a developmental lens for testing between these theories. These studies present a force-choice method of measuring children’s sensitivity to confidence by asking how closely they can tell apart two states of confidence. This method of assessing confidence allows me to narrow in on the properties of metacognition that develop independently of children’s overconfidence biases and developing linguistic knowledge. In Chapter 2, I use this measure to look for developmental change associated with confidence judgments when controlling for decision noise, finding age-related change consistent with the Inferential accounts. In Chapter 3, I test whether children reason about confidence using encapsulated systems or a broader metacognitive system, and probe whether these judgments share a unit of representation, finding evidence for both within the domain of perceptual judgments as predicted again by Inferential accounts. In Chapter 4, I investigate whether confidence is processed so broadly as to include reasoning about others’ abilities, but do not find strong evidence of this, suggesting a limit on the generality of confidence processing. All together, this dissertation shows that far from being subject to the whims of others, children possess a sense of confidence that combines multiple sources in information to create broadly-usable assessments of truth in the world.Arts, Faculty ofPsychology, Department ofGraduat

Certainty in numerical judgments develops independently of the Approximate Number System

Recent work has shown that the precision with which children reason about their ANS certainty improves with age: when making simple number discrimination decisions, like deciding whether there are more blue or yellow dots on the screen, older children are better able to differentiate trials that they answered correctly vs. incorrectly. Here, in two experiments, we examine whether the age-related improvement in ANS certainty is accounted for by children’s: (1) increasing ability to properly “calibrate” their certainty judgements (i.e., a reduction in over-confidence with age); (2) improving precision of the ANS representations themselves; and/or (3) the improvement of children’s ability to represent and reason about certainty in general. By testing children in a child-friendly “relative” certainty task, we find that 3–7 year-olds’ (N = 161) certainty in their ANS decisions develops independently of both ANS acuity and calibration abilities. These results hold even when non-numeric perceptual features, such as the density and cumulative area, are controlled for. We discuss these results in a broader context of children’s general ability to reason about certainty and confidence

Are Children’s Judgments of Another’s Accuracy Linked to Their Metacognitive Confidence Judgments?

The world can be a confusing place, which leads to a significant challenge: how do we figure out what is true? To accomplish this, children possess two relevant skills: reasoning about the likelihood of their own accuracy (metacognitive confidence) and reasoning about the likelihood of others’ accuracy (mindreading). Guided by Signal Detection Theory and Simulation Theory, we examine whether these two self- and other-oriented skills are one in the same, relying on a single cognitive process. Specifically, Signal Detection Theory proposes that confidence in a decision is purely derived from the imprecision of that decision, predicting a tight correlation between decision accuracy and confidence. Simulation Theory further proposes that children attribute their own cognitive experience to others when reasoning socially. Together, these theories predict that children’s self and other reasoning should be highly correlated and dependent on decision accuracy. In four studies (N = 374), children aged 4–7 completed a confidence reasoning task and selective social learning task each designed to eliminate confounding language and response biases, enabling us to isolate the unique correlation between self and other reasoning. However, in three of the four studies, we did not find that individual differences on the two tasks correlated, nor that decision accuracy explained performance. These findings suggest self and other reasoning are either independent in childhood, or the result of a single process that operates differently for self and others