Reduced face identity aftereffects in relatives of children with autism.

Autism is a pervasive developmental condition with complex aetiology. To aid the discovery of genetic mechanisms, researchers have turned towards identifying potential endophenotypes - subtle neurobiological or neurocognitive traits present in individuals with autism and their "unaffected" relatives. Previous research has shown that relatives of individuals with autism exhibit face processing atypicalities, which are similar in nature albeit of lesser degree, to those found in children and adults with autism. Yet very few studies have examined the underlying mechanisms responsible for such atypicalities. Here, we investigated whether atypicalities in adaptive norm-based coding of faces are present in relatives of children with autism, similar to those previously reported in children with autism. To test this possibility, we administered a face identity aftereffect task in which adaptation to a particular face biases perception towards the opposite identity, so that a previously neutral face (i.e., the average face) takes on the computationally opposite identity. Parents and siblings of individuals with autism showed smaller aftereffects compared to parents and siblings of typically developing children, especially so when the adapting stimuli were located further away from the average face. In addition, both groups showed stronger aftereffects for adaptors far from the average than for adaptors closer to the average. These results suggest that, in relatives of children with autism, face-coding mechanism are similar (i.e., norm-based) but less efficient than in relatives of typical children. This finding points towards the possibility that diminished adaptive mechanisms might represent a neurocognitive endophenotype for autism

Adverse selection and competing deposit insurance systems in pre-depression Texas

In 1910, Texas instituted a highly unique deposit insurance program for its state chartered banks consisting of two separate plans: the depositors guaranty fund, similar in operation to the deposit insurance schemes adopted in several other states; and the depositors bond security system, which required the procurement of a privately issued insurance policy. We hypothesize that the provision of a choice in funds led to risk-sorting among the banks, with the relatively conservative institutions opting for the comparatively rigorous bond security system. Employing a probit model with heteroskedasticity, the evidence we obtain from balance sheet data recorded at the time the banks were required to enlist in an insurance plan indicates that such was the case, as the alternative plan relying on privately issued insurance was widely unpopular except among relatively conservative and well-managed institutions.Deposit insurance

Childhood obesity: Evidence for distinct early and late environmental determinants a 12-year longitudinal cohort study (EarlyBird 62)

Background/objective:The prevalence of childhood obesity continues to rise in most countries, but the exposures responsible remain unclear. The shape of the body mass index (BMI) distribution curve defines how a population responds, and can be described by its three parameters-skew (L), median (M) and variance (S). We used LMS analysis to explore differences in the BMI trajectories of contemporary UK children with those of 25 years ago, and to draw inferences on the exposures responsible.Subjects/methods:We applied Cole's LMS method to compare the BMI trajectories of 307 UK children (EarlyBird cohort) measured annually from 5-16 years (2000-2012) with those of the BMI data set used to construct the UK 1990 growth centiles, and used group-based trajectory modelling (GBTM) to establish whether categorical trajectories emerged.Results:Gender-specific birth weights were normally distributed and similar between both data sets. The skew and variance established by 5 years in the 1990 children remained stable during the remainder of their childhood, but the pattern was different for children 25 years on. The skew at 5 years among the EarlyBird children was greatly exaggerated, and involved selectively the offspring of obese parents, but returned to 1990 levels by puberty. As the skew diminished, so the variance in BMI rose sharply. The median BMI of the EarlyBird children differed little from that of 1990 before puberty, but diverged from it as the variance rose. GBTM uncovered four groups with distinct trajectories, which were related to parental obesity.Conclusions:There appear to be two distinct environmental interactions with body mass among contemporary children, the one operating selectively according to parental BMI during early childhood, the second more generally in puberty.Bright Future TrustBUPA FoundationPeninsula FoundationKirby Laing TrustEarlyBird Diabetes Trus

The timecourse of higher-level face aftereffects

AbstractPerceptual aftereffects for simple visual attributes processed early in the cortical hierarchy increase logarithmically with adapting duration and decay exponentially with test duration. This classic timecourse has been reported recently for a face identity aftereffect [Leopold, D. A., Rhodes, G., Müller, K.-M., & Jeffery, L. (2005). The dynamics of visual adaptation to faces. Proceedings of the Royal Society of London, Series B, 272, 897–904], suggesting that the dynamics of visual adaptation may be similar throughout the visual system. An alternative interpretation, however, is that the classic timecourse is a flow-on effect of adaptation of a low-level, retinotopic component of the face identity aftereffect. Here, we examined the timecourse of the higher-level (size-invariant) components of two face aftereffects, the face identity aftereffect and the figural face aftereffect. Both showed the classic pattern of logarithmic build-up and exponential decay. These results indicate that the classic timecourse of face aftereffects is not a flow-on effect of low-level retinotopic adaptation, and support the hypothesis that dynamics of visual adaptation are similar at higher and lower levels of the cortical visual hierarchy. They also reinforce the perceptual nature of face aftereffects, ruling out demand characteristics and other post-perceptual factors as plausible accounts

Adaptive norm-based coding of facial identity

AbstractIdentification of a face is facilitated by adapting to its computationally opposite identity, suggesting that the average face functions as a norm for coding identity [Leopold, D. A., O’Toole, A. J., Vetter, T., & Blanz, V. (2001). Prototype-referenced shape encoding revealed by high-level aftereffects. Nature Neuroscience, 4, 89–94; Leopold, D. A., Rhodes, G., Müller, K. -M., & Jeffery, L. (2005). The dynamics of visual adaptation to faces. Proceedings of the Royal Society of London, Series B, 272, 897–904]. Crucially, this interpretation requires that the aftereffect is selective for the opposite identity, but this has not been convincingly demonstrated. We demonstrate such selectivity, observing a larger aftereffect for opposite than non-opposite adapt-test pairs that are matched on perceptual contrast (dissimilarity). Component identities were also harder to detect in morphs of opposite than non-opposite face pairs. We propose an adaptive norm-based coding model of face identity

Adults’ facial impressions of children’s niceness, but not shyness, show modest accuracy

Acknowledgements: We are grateful to the parents and children who helped make this research possible. We would also like to thank Romina Palermo for providing us the opportunity to contact her sample of parent and child participants, and to use some of her existing data. Finally, we would like to thank the examiners who provided thoughtful comments on an earlier draft of this paper presented in a thesis. JC, CS, LJ and GR conceived the study and edited the manuscript. JC programmed the experiment, collected undergraduate participant data, performed the statistical analyses, and drafted the first manuscript. EB coordinated image collection. All authors participated in the study design, and read and approved the final manuscript. Funding: This research was supported by an Australian Research Council (ARC) Centre of Excellence Grant award to GR [CE110001021], ARC Discovery Early Career Research Award to CS [DE190101043], ARC Discovery Award to GR and CS [DP170104602], ARC Discovery Award to LJ [DP140101743] and a Research Training Program Stipend to JC.Peer reviewedPostprin

Modulation of Telomeres in Alternative Lengthening of Telomeres Type I Like Human Cells by the Expression of Werner Protein and Telomerase

The alternative lengthening of telomeres (ALT) is a recombination-based mechanism of telomere maintenance activated in 5–20% of human cancers. In Saccharomyces cerevisiae, survivors that arise after inactivation of telomerase can be classified as type I or type II ALT. In type I, telomeres have a tandem array structure, with each subunit consisting of a subtelomeric Y′ element and short telomere sequence. Telomeres in type II have only long telomere repeats and require Sgs1, the S. cerevisiae RecQ family helicase. We previously described the first human ALT cell line, AG11395, that has a telomere structure similar to type I ALT yeast cells. This cell line lacks the activity of the Werner syndrome protein, a human RecQ helicase. The telomeres in this cell line consist of tandem repeats containing SV40 DNA, including the origin of replication, and telomere sequence. We investigated the role of the SV40 origin of replication and the effects of Werner protein and telomerase on telomere structure and maintenance in AG11395 cells. We report that the expression of Werner protein facilitates the transition in human cells of ALT type I like telomeres to type II like telomeres in some aspects. These findings have implications for the diagnosis and treatment of cancer

Facial expression coding in children and adolescents with autism: Reduced adaptability but intact norm-based coding

Individuals with autism spectrum disorder (ASD) can have difficulty recognizing emotional expressions. Here we asked whether the underlying perceptual coding of expression is disrupted. Typical individuals code expression relative to a perceptual (average) norm that is continuously updated by experience. This adaptability of face coding mechanisms has been linked to performance on various face tasks. We used an adaptation aftereffect paradigm to characterize expression coding in children and adolescents with autism. We asked whether face expression coding is less adaptable in autism and whether there is any fundamental disruption of norm-based coding. If expression coding is norm-based, then the face aftereffects should increase with adaptor expression strength (distance from the average expression). We observed this pattern in both autistic and typically developing participants, suggesting that norm-based coding is fundamentally intact in autism. Critically, however, expression aftereffects were reduced in the autism group, indicating that expression-coding mechanisms are less readily tuned by experience. Reduced adaptability has also been reported for coding of face identity and gaze direction. Thus there appears to be a pervasive lack of adaptability in face-coding mechanisms in autism, which could contribute to face processing and broader social difficulties in the disorder