Faculty Bibliography

Standing and walking generate information about friction underfoot. Five experiments examined whether walkers use such perceptual information for prospective control of locomotion. In particular, do walkers integrate information about friction underfoot with visual cues for sloping ground ahead to make adaptive locomotor decisions? Participants stood on low-, medium-, and high-friction surfaces on a flat platform and made perceptual judgments for possibilities for locomotion over upcoming slopes. Perceptual judgments did not match locomotor abilities: Participants tended to overestimate their abilities on low-friction slopes and underestimate on high-friction slopes (Experiments 1-4). Accuracy improved only for judgments made while participants were in direct contact with the slope (Experiment 5), highlighting the difficulty of incorporating information about friction underfoot into a plan for future actions.

INTRODUCTION: Evidence suggests that mothers are negative and critical when talking about their children with behaviour problems. However the association with specific types of behaviour problems and the influence of both child and adult psychopathology on these relationships require further clarification. METHODS: Speech samples were gathered from mothers of 100 school-aged boys and coded using standard Expressed Emotion (EE) categories. Levels of maternal and child psychopathology were ascertained using standardised questionnaires completed by the mother. RESULTS: There were significant and positive correlations between criticism and child ADHD, conduct and emotional symptoms respectively. There were also significant and negative correlations between EOI and child ADHD and conduct problems. CONCLUSIONS: The findings of the current study suggest that when considered together EE is driven more by the child rather than by maternal characteristics and these effects are specific to conduct and emotional problems. The implications of the findings are discussed

BACKGROUND: Attaining a developmentally sensitive nosology for preschool disruptive behavior requires characterization of the features that distinguish it from the normative misbehavior of this developmental period. We hypothesize that quality of behavior and its pervasiveness across contexts are critical dimensions for clinical discrimination in young children and propose that structured diagnostic observation provides a systematic method for their identification. We use the Disruptive Behavior Diagnostic Observation Schedule (DB-DOS) to examine whether: (a) observed quality and pervasiveness of behavior distinguishes preschoolers with clinically concerning disruptive behavior from typically developing preschoolers, and (b) observed pattern of clinically salient behavior predicts impairment above and beyond maternal report of behavioral frequency. METHODS: Participants are a behaviorally heterogeneous sample of preschoolers (N = 327). Diagnostic methods developed for clinical assessment of preschoolers were used to classify children as (a) Non-Disruptive, (b) Sub-Clinical, or (c) Disruptive. Child behavior was coded based on interactions with parent and examiner during the DB-DOS. RESULTS: Quality and pervasiveness of observed behaviors during the DB-DOS significantly distinguished the three behavioral groups. Discriminative utility varied depending on the comparison. With few exceptions, clinically concerning patterns on the DB-DOS added significant incremental utility in predicting impairment. CONCLUSIONS: Observed patterns of clinically salient behavior show promise for advancing developmentally-informed characterization of disruptive behavior within the preschool period

Perceived social-evaluative threat triggers the hypothalamic-pituitary adrenal (HPA) axis, resulting in cortisol release. The current study examined the effects of varying the levels of social-evaluative threat on the stress response. Sixty healthy men (mean age + 23.17 +/- 3.89 years) underwent a public speaking task. Four conditions were established on the basis of panel location (inside or outside the room) and number of panelists (one or two). It was hypothesized that these variations affect salivary cortisol and physiological responses in a gradient manner. The task elicited significant cortisol and blood pressure changes for all conditions, but no difference between the groups was found, suggesting that all conditions were equally stressful. Study conclusions were that, for men, the visual presence of a panel is not necessary to elicit a cortisol response. Furthermore, increasing the number of judges does not increase the intensity of the stress response in a gradual manner, but rather seems to follow a threshold pattern. Future studies should include women and try to define the possible threshold to activate the HPA axis

In 118 children followed from age 2 to 5 (59 with autism, 24 with PDD-NOS and 35 with non-spectrum developmental disabilities), age 2 and age 3 scores of non-verbal ability, receptive communication, expressive communication and socialization were compared as predictors of receptive and expressive language at age 5. Non-verbal cognitive ability at age 2 was generally the strongest predictor of age 5 language, while at age 3 communication scores were a stronger predictor of age 5 language for children with autism. Early joint attention as well as vocal and motor imitation skills were more impaired in children who did not develop language by age 5 (but had relatively strong non-verbal cognitive skills) than in children who did develop language by 5

This study examined change prospectively in autism symptoms and maladaptive behaviors during a 4.5 year period in 241 adolescents and adults with an autism spectrum disorder who were 10-52 years old (mean = 22.0) when the study began. Although many individuals' symptoms remained stable, a greater proportion of the sample experienced declines than increases in their level of autism symptoms and maladaptive behaviors, and there were significant improvements in mean levels of symptoms. Individuals with mental retardation had more autism symptoms and maladaptive behaviors than those without mental retardation, and they improved less over time. Compared to adolescents, older sample members (31 and older) had fewer maladaptive behaviors and experienced more improvement in these behaviors over time

Regression of a scalar response on signal predictors, such as near-infrared (NIR) spectra of chemical samples, presents a major challenge when, as is typically the case, the dimension of the signals far exceeds their number. Most solutions to this problem reduce the dimension of the predictors either by regressing on components [e.g., principal component regression (PCR) and partial least squares (PLS)l or by smoothing methods, which restrict the coefficient function to the span of a spline basis. This article introduces functional versions of PCR and PLS, which combine both of the foregoing dimension-reduction approaches. Two versions of functional PCR are developed, both using B-splines and roughness penalties. The regularized-components version applies such a penalty to the construction of the principal components (i.e., it uses functional principal components), whereas the regularized-regression version incorporates a penalty in the regression. For the latter form of functional PCR, the penalty parameter may be selected by generalized cross-validation, restricted maximum likelihood (REML), or a minimum mean integrated squared error criterion. Proceeding similarly, we develop two versions of functional PLS. Asymptotic convergence properties of regularized-regression functional PCR are demonstrated. A simulation study and split-sample validation with several NIR spectroscopy data sets indicate that functional PCR and functional PLS, especially the regularized-regression versions with REML, offer advantages over existing methods in terms of both estimation of the coefficient function and prediction of future observations. $$:

The endocannabinoid system is an important regulator of hepatic fibrogenesis. In this study, we determined the effects of 2-arachidonoyl glycerol (2-AG) on hepatic stellate cells (HSCs), the main fibrogenic cell type in the liver. Culture-activated HSCs were highly susceptible to 2-AG-induced cell death with >50% cell death at 10 microM after 18 h of treatment. 2-AG-induced HSC death showed typical features of apoptosis such as PARP- and caspase 3-cleavage and depended on reactive oxygen species (ROS) formation. Confocal microscopy revealed mitochondria as primary site of ROS production and demonstrated mitochondrial depolarization and increased mitochondrial permeability after 2-AG treatment. 2-AG-induced cell death was independent of cannabinoid receptors but required the presence of membrane cholesterol. Primary hepatocytes were resistant to 2-AG-induced ROS induction and cell death but became susceptible after GSH depletion suggesting antioxidant defenses as a critical determinant of 2-AG sensitivity. Hepatic levels of 2-AG were significantly elevated in two models of experimental fibrogenesis and reached concentrations that are sufficient to induce death in HSCs. These findings suggest that 2-AG may act as an antifibrogenic mediator in the liver by inducing cell death in activated HSCs but not hepatocytes

The aim of our study was to investigate the impact of maternal exposure to family violence, maltreatment, and related posttraumatic stress disorder (PTSD) on young children's mental representations of self and caregivers. Participant mothers (n=24) and children (n=25) were recruited from a referred sample when they were 4-7 years old. Maternal report and child story stem narratives were used. Mother's experience of domestic violence and severity of violence-related PTSD symptoms robustly predicted more dysregulated aggression, attentional bias to danger and distress, as well as more avoidance of and withdrawal from conflicts presented in the children's story stems. Less narrative coherence was also noted. Traumatized mothers experience and symptoms prior to their child's turning 4 years old adversely affected their child's mental representations from 4-7 years.