Block design performance in the Williams syndrome phenotype: A problem with mental imagery?

Williams syndrome (WS) is a rare genetic disorder which, among other characteristics, has a distinctive cognitive profile. Non-verbal abilities are generally poor in relation to verbal abilities, but also show varying levels of ability in relation to each other. Performance on block construction tasks represents arguably the weakest non-verbal ability in WS. In this study we examined two requirements of block construction tasks in 21 individuals with WS and 21 typically developing (TD) control individuals. The Squares task, a novel two-dimensional block construction task, manipulated patterns by segmentation and perceptual cohesiveness to investigate the first factor, processing preference (local or global), and by obliqueness to examine the second factor, the ability to use mental imagery. These two factors were investigated directly by the Children?s Embedded Figures Test (CEFT; Witkin, Oltman, Raskin & Karp, 1971) and a mental rotation task respectively. Results showed that individuals with WS did not differ from the TD group in their processing style. However, the ability to use mental imagery was significantly poorer in the WS group than the TD group. This suggests that weak performance on the block construction tasks in WS may relate to an inability to use mental imagery

Divided attention, selective attention and drawing: Processing preferences in Williams syndrome are dependent on the task administered

The visuo-spatial abilities of individuals with Williams syndrome (WS) have consistently been shown to be generally weak. These poor visuo-spatial abilities have been ascribed to a local processing bias by some [30] and conversely, to a global processing bias by others [24]. In this study, two identification versions and one drawing version of the Navon hierarchical processing task, a non-verbal task, were employed to investigate this apparent contradiction. The two identification tasks were administered to 21 individuals with WS, 21 typically developing individuals, matched by non-verbal ability, and 21 adult participants matched to the WS group by mean chronological age. The third, drawing task was administered to the WS group and the TD controls only. It was hypothesised that the WS group would show differential processing biases depending on the type of processing the task was measuring. Results from two identification versions of the Navon task measuring divided and selective attention showed that the WS group experienced equal interference from global to local as from local to global levels, and did not show an advantage of one level over another. This pattern of performance was broadly comparable to that of the control groups. The third task, a drawing version of the Navon task, revealed that individuals with WS were significantly better at drawing the local form in comparison to the global figure, whereas the typically developing control group did not show a bias towards either level. In summary, this study demonstrates that individuals with WS do not have a local or a global processing bias when asked to identify stimuli, but do show a local bias in their drawing abilities. This contrast may explain the apparently contrasting findings from previous studies

Linking working memory and long-term memory: A computational model of the learning of new words

The nonword repetition (NWR) test has been shown to be a good predictor of children’s vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of children’s vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The model’s behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity. Keywords: EPAM, working memory, long-term memory, nonword repetition, vocabulary acquisition, developmental change

A novel selective 11b-hydroxysteroid dehydrogenase type 1 inhibitor prevents human adipogenesis.

Glucocorticoid excess increases fat mass, preferentially within omental depots; yet circulating cortisol concentrations are normal in most patients with metabolic syndrome (MS). At a pre-receptor level, 11b-hydroxysteroid dehydrogenase type 1 (11b-HSD1) activates cortisol from cortisone locally within adipose tissue, and inhibition of 11b-HSD1 in liver and adipose tissue has been proposed as a novel therapy to treat MS by reducing hepatic glucose output and adiposity. Using a transformed human subcutaneous preadipocyte cell line (Chub-S7) and human primary preadipocytes, we have defined the role of glucocorticoids and 11b-HSD1 in regulating adipose tissue differentiation. Human cells were differentiated with 1.0 mM cortisol (F), or cortisone (E) with or without 100 nM of a highly selective 11b-HSD1 inhibitor PF-877423. 11b-HSD1 mRNA expression increased across adipocyte differentiation (P!0.001, nZ4), which was paralleled by an increase in 11b-HSD1 oxo-reductase activity (from nil on day 0 to 5.9G1.9 pmol/mg per h on day 16,P!0.01, nZ7). Cortisone enhanced adipocyte differentiation; fatty acid-binding protein 4 expression increased 312-fold (P!0.001) and glycerol-3-phosphate dehydrogenase 47-fold (P!0.001) versus controls. This was abolished by co-incubation with PF-877423. In addition, cellular lipid content decreased significantly. These findings were confirmed in the primary cultures of human subcutaneous preadipocytes. The increase in 11b-HSD1 mRNA expression and activity is essential for the induction of human adipogenesis. Blocking adipogenesis with a novel and specific 11b-HSD1 inhibitor may represent a novel approach to treat obesity in patients with MS

Number word use in toddlerhood is associated with number recall performance at seven years of age

Previous studies have shown that verbal working memory and vocabulary acquisition are linked in early childhood. However, it is unclear whether acquisition of a narrow range of words during toddlerhood may be particularly related to recall of the same words later in life. Here we asked whether vocabulary acquisition of number words, location and quantifier terms over the first three years of life are associated with verbal and visuospatial working memory at seven years. Our results demonstrate that children who produced more number words between 20-26 months and started to produce the number words 1-10 earlier showed greater number recall at 7 years of age. This link was specific to numbers and neither extended to quantifier and location terms nor verbal and visuospatial working memory performance with other stimuli. These findings suggest a category-specific link between the mental lexicon of number words and working memory for numbers at an early age. © 2014 Libertus et al

HIV infection significantly reduces lipoprotein lipase which remains low after 6 months of antiretroviral therapy

Purpose of the study Fractional clearance rate of apolipoprotein B100-containing lipoproteins is reduced in HIV infection before and after antiretroviral (ARV) treatment [1]. We compared lipoprotein lipase (LPL) activity and gene expression in HIV-positive subjects before and 6 months after ARV with HIV-negative controls. Methods Fasting blood post heparin total and hepatic lipase activity,adiponectin, leptin, insulin, glucose, and lipid measurementswere made in 32 HIV-infected and 15 HIVnegative controls. LPL was estimated by subtractinghepatic lipase from total lipase. Adiponectin, LPL andhormone sensitive lipase (HSL) gene expression weremeasured from iliac crest subcutaneous fat biopsies.Patients were tested before, and 6 months after randomisation to AZT/3TC (n = 15) or TDF/FTC (n = 17) with EFV.Between-group comparison was by Mann-Whitney andpaired samples by the Wilcoxon signed rank tests. Summary of results There were no differences in gender, ethnicity, baseline BMI, regional fat distribution (whole body DEXA) and visceral (VAT) and subcutaneous fat (SAT) measured by abdominal CT scans between controls and patients. Trunk fat/BMI ratio, VAT and VAT:SAT ratio significantly increased after 6-month ARV therapy (p = 0.01). There were no differences between groups in serum NEFA,HOMA and leptin levels. Selected other results are shown in Table 1. Conclusion Post heparin lipoprotein lipase activity is reduced in HIV and does not return to control levels after 6 months of ARV therapy. AZT-containing regimens are associated with a greater increase in LPL, LPL gene expression and plasma adiponectin than TDF

The preschool repetition test: An evaluation of performance in typically developing and clinically referred children

Purpose: To determine the psychometric properties of the Preschool Repetition Test (Roy & Chiat, 2004); to establish the range of performance in typically developing children and variables affecting this; and to compare the performance of clinically referred children. Method: The PSRep Test comprises 18 words and 18 phonologically matched nonwords systematically varied for length and prosodic structure. This test was administered to a ‘typical’ sample of children aged 2;0–4;0 (n=315) and a ‘clinic’ sample of children aged 2;6-4;0 (n=168), together with language assessments. Results: Performance in the typical sample was independent of gender and SES, but was affected by age, item length, and prosodic structure, and was moderately correlated with receptive vocabulary. Performance in the clinic sample was significantly poorer, but revealed similar effects of length and prosody, and similar relations to language measures overall, with some notable exceptions. Test-retest and interrater reliability were high. Conclusions: The PSRep Test is a viable and informative test. It differentiates within and between ‘typical’ and ‘clinic’ samples of children, and reveals some unusual profiles within the clinic sample. These findings lay the foundations for a follow-up study of the clinic sample to investigate the predictive value of the test

Gender Assignment to Spanish Pseudowords by Monolingual and Basque-Spanish Bilingual Children

This study examines gender marking in the Spanish of Basque-Spanish bilingual children. We analyze data collected via a production task designed to elicit 48 DPs, controlling for gender of referents and for number and types of morphological cues to grammatical gender. The goals were to determine the extent to which participants rely on biological cues (female referent =\u3eFEM gender, male referent =\u3eMASC gender) and morpho-phonological cues (-a ending =\u3eFEM, -o ending =\u3eMASC, others =\u3eMASC or FEM) to assign gender to pseudowords/novel words; and whether bilinguals’ language dominance (Spanish strong/weak) has an effect. Data were collected from 49 5- to 6-year-old Spanish-speaking children—28 monolingual L1 Spanish (L1Sp) and 21 Basque-dominant (L1 Basque-L2 Spanish) bilinguals (BDB). Results reveal a general preference for MASC gender across conditions, especially in BDB children, who produced masculine modifiers for 83% of items, while the L1Sp children did so for only 63% of items. Regression analyses show that for both groups, morphological cues have more weight than the nature of the referent in participants’ assignment of gender to novel words, and that the L1Sp group is more attentive to FEM morphological markers than the BDB group, pointing towards the existence of differences in the strength of cue-patterns for gender marking

Lexicality and frequency in specific language impairment: accuracy and error data from two nonword repetition tests

Purpose: Deficits in phonological working memory and deficits in phonological processing have both been considered potential explanatory factors in Specific Language Impairment (SLI). Manipulations of the lexicality and phonotactic frequency of nonwords enable contrasting predictions to be derived from these hypotheses. Method: 18 typically developing (TD) children and 18 children with SLI completed an assessment battery that included tests of language ability, non-verbal intelligence, and two nonword repetition tests that varied in lexicality and frequency. Results: Repetition accuracy showed that children with SLI were unimpaired for short and simple high lexicality nonwords, whereas clear impairments were shown for all low lexicality nonwords. For low lexicality nonwords, greater repetition accuracy was seen for nonwords constructed from high over low frequency phoneme sequences. Children with SLI made the same proportion of errors that substituted a nonsense syllable for a lexical item as TD children, and this was stable across nonword length. Conclusions: The data show support for a phonological processing deficit in children with SLI, where long-term lexical and sub-lexical phonological knowledge mediate the interpretation of nonwords. However, the data also suggest that while phonological processing may provide a key explanation of SLI, a full account is likely to be multi-faceted