23 research outputs found
No evidence for altered up- and downregulation of brain activity in visual cortex during illusory shape perception in autism
Autism spectrum disorder (ASD) may be marked by an altered balance between sensory input and prior expectations. Because many illusions rely on integrating sensory input with prior information such as spatial context, individuals with ASD may therefore be less susceptible to visual illusions than typically developing (TD) individuals. Yet empirical evidence on the matter is rather divergent, varying depending on the type of illusion, study procedure, and population. Visual illusions lead to neural activity alterations in the visual system. In the so-called Kanizsa illusion, these are likely caused by top-down feedback to V1. Here we tested the hypothesis that a reduced susceptibility to illusions in ASD would manifest as diminished modulation of V1 activity by illusions, using functional magnetic resonance imaging (fMRI). We presented 22 adolescents with ASD and 22 age-, gender-, and intelligence-matched TD controls with displays that consisted of three circular inducers. These either formed an illusory triangle (Kanizsa illusion) or not. We identified regions in primary visual cortex (V1) that corresponded to (the visual field locations of) the illusory triangle and its inducers, and recorded their visual response. Previous research in healthy volunteers has shown a specific pattern of up- and down-regulation in regions of V1 that process the shape and inducers, respectively. Here, we replicated this pattern of up- and downregulation in V1, in both the TD and ASD groups, with no differences between groups. This suggests that illusory shape processing in primary visual cortex is equally present in ASD, suggesting unimpaired processing of spatial context
As good as it gets? A meta-analysis and systematic review of methodological quality of heart rate variability studies in functional somatic disorders
Autonomic nervous system (ANS) dysfunction is a potential mechanism connecting psychosocial stress to functional somatic disorders (FSD), such as chronic fatigue syndrome, fibromyalgia and irritable bowel syndrome. We present the first meta-analysis and systematic review of methodological study quality on the association between cardiac ANS dysfunction, measured as parasympathetic nervous system (PNS) activity using heart rate variability (HRV), and FSD. Literature search revealed 23 available studies including data on 533 FSD patients. Meta-analysis on a subgroup of 14 studies with suitable outcome measures indicated lower PNS activity in FSD patients compared to controls (weighted standardized mean difference (SMD) = -0.32, 95% CI -0.63 to -0.01, p = 0.04). The reliability of this summary estimate was, however, significantly limited by unexplained heterogeneity in the effect sizes and potential publication bias (weighted SMD after correction for funnel plot asymmetry = 0.01, 95% CI -0.34 to 0.36, p = 0.95). The systematic review of overall methodological quality of HRV studies in FSD demonstrates that there is substantial room for improvement, especially in selection of healthy control subjects, blinding of researchers performing HRV measurements, report of adequate HRV outcomes, and assessment of and adjustment for potential confounders. Methodological study quality was, however, not a significant predictor of study findings. We conclude that current available evidence is not adequate to firmly reject or accept a role of ANS dysfunction in FSD. Quality criteria and recommendations to improve future research on HRV in FSD are provided. (C) 2009 Elsevier B.V. All rights reserved
Meta-analysis and meta-regression of hypothalamic-pituitary-adrenal axis activity in functional somatic disorders
Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is the most investigated biological risk marker in functional somatic disorders (FSDs), such as chronic fatigue syndrome (CFS), fibromyalgia (FM), and irritable bowel syndrome (IBS). Our aim was to assess whether there is an association between basal hypocortisolism and FSD and to identify potential moderators of this association. Meta-analysis on 85 studies revealed that although basal cortisol levels were generally lower in FSD subjects compared to controls, this association did not reach statistical significance (SMD -0.07, 95% CI -0.17 to 0.04, p = 0.241). However, when the three FSD were assessed separately, statistically significant basal hypocortisolism was observed in CFS subjects compared to controls (SMD -0.14, 95% CI -0.28 to 0.00, p = 0.047), but not in FM or IBS. When all potential moderators were entered into a meta-regression analysis, only type of FSD and female gender were significant independent predictors of basal hypocortisolism. In conclusion, we did not find evidence to consider all three main FSD as hypocortisolemic disorders, as significant reduction in basal cortisol compared to healthy controls was only found in CFS and in females with FM, but not in IBS. (C) 2011 Elsevier B.V. All rights reserved
Composition, species richness and similarity of ichthyofaunas in eelgrass Zostera capensisbeds of southern Africa
This study collates published and unpublished data on the ichthyofaunas associated with beds of eelgrass Zostera capensis in eight estuaries and one lagoon in southern Africa. These macrophyte beds are utilized predominantly by small teleosts, both species which breed in the estuary and juvenile marine fish. By far the most abundant of the 97 species of fish recorded in these beds were Atherina breviceps, Gilchristella aestuaria, Liza dumerilii, Liza richardsonii and Rhabdosargus holubi. Classification grouped the ichthyofaunas of the six warm-temperate estuaries in the South-Eastern and Southern Cape at a similarity level >50 per cent. Ordination produced a similar clustering and also demonstrated that the subtropical Richards Bay and warm-temperate Mngazana estuary, together with the cold-temperate Langebaan Lagoon, were outliers. Classification and ordination showed that, within an estuary, the ichthyofaunas of dense and sparse Zostera areas were more similar than either was with those of non-vegetated areas. The species richness (R) of fish within eelgrass habitats along the southern African coast tended to decrease from north-east to south-west, a trend attributable to an attenuation in the number of tropical/subtropical Indo-Pacific species. The numerically dominant fish families in eelgrass beds in South Africa showed a greater degree of overlap with those of south-eastern Australia than with those of either southern Japan or eastern North America
Plasma enterolignans are not associated with nonfatal myocardial infarction risk.
Plant lignans present in foods such as whole grains, seeds and nuts, fruits and vegetables, and beverages. Plant lignans are converted by intestinal bacteria into the enterolignans enterodiol and enterolactone. Up to now, epidemiological evidence for a protective role of enterolignans on cardiovascular diseases is limited and inconsistent. We investigated the association between plasma enterodiol and enterolactone and nonfatal myocardial infarction risk in a prospective study. During follow-up (1987-1998) of 15,107 subjects, aged 20-59 years, 236 incident nonfatal myocardial infarction cases were diagnosed. Controls (n = 283) were frequency matched to the cases on age, sex, and study center. No statistically significant associations between plasma enterodiol and enterolactone and risk of nonfatal myocardial infarction were detected. The odds ratio for the highest versus the lowest quartile of enterodiol was 1.21 (95% confidence interval (CI): 0.70, 2.12; p for trend = 0.74), and that of enterolactone 1.51 (95% CI: 0.87, 2.61; p for trend = 0.12) after adjustment for known dietary risk factors for coronary heart disease. No effect modification was observed for sex, menopausal status, or smoking status. Our results do not support the hypothesis that high plasma enterodiol or enterolactone concentrations are associated with a reduced risk of nonfatal myocardial infarctio
European Policy Brief. The Assets of Urban Diversity
City policy agendas are much more geared to the assets of diversity than national agendas. Careful city planning can link diversity policies to spatial interventions and stimulates the inclusion of new groups, such as refugees. A hopeful sign for cities is that younger generations are more at ease with diversity than older ones and tend to focus more on what unites us than what separates us. This policy brief, therefore, calls for a positive approach to diversity and presents cities as spaces of hope
European Policy Brief. The Assets of Urban Diversity
City policy agendas are much more geared to the assets of diversity than national agendas. Careful city planning can link diversity policies to spatial interventions and stimulates the inclusion of new groups, such as refugees. A hopeful sign for cities is that younger generations are more at ease with diversity than older ones and tend to focus more on what unites us than what separates us. This policy brief, therefore, calls for a positive approach to diversity and presents cities as spaces of hope