Apraxia and Alzheimer’s Disease: Review and Perspectives

Apraxia is one of the cognitive deficits that characterizes Alzheimer’s disease. Despite its prevalence and relevance to diagnosing Alzheimer’s disease, this topic has received little attention and is without comprehensive review. The review herein is aimed to fill this gap by first presenting an overview of the impairment caused in different clinical situations: pantomime of tool use, single tool use, real tool use, mechanical problem solving, function and manipulation knowledge tasks, and symbolic/meaningless gestures. On the basis of these results, we then propose alternative interpretations regarding the nature of the underlying mechanisms impaired by the disease. Also presented are principal methodological issues precluding firm conclusions from being drawn.     

Critical Evaluation of Porter et al.'s Organizational Commitment Questionnaire: Implications for Researchers

Organizational commitment is a useful construct for understanding employee behavior. The Organizational Commitment Questionnaire (Porter et al. 1974) has been used extensively to operationalize this construct, but its dimensionality is unclear. The present work assesses the dimensionality of the OCQ using two sales force samples.     

The clustering of health-related occupational stressors among contemporary wage-earners

In this study, it is investigated whether a typology can be imposed upon a sample of wage-earners, based on their exposure to a broad number of occupational stressors: quantitative, emotional, and physical demands, repetitive movements, atypical schedules, low job control, relationships with superiors, job insecurity, and bullying behaviour. Also associations between this typology and measures of emotional problems (EP) and musculoskeletal complaints (MC) are tested. Logistic regression and a latent class cluster analysis are performed on a representative sample of 10,074 Flemish (Belgian) employees. Five clusters are revealed: “low stress”, “high stress”, “manual-passive”, “human contact”, and “high demand”. These clusters are showing a clear socioeconomic distribution and distinct associations with EP and MC—with the “high stress cluster” being the most problematic. Health-damaging occupational stress clusters are prevalent at both higher and lower socioeconomic positions. This is suggesting a complex relationship between occupational stressors and socioeconomic health variations.     

Taï chimpanzees use botanical skills to discover fruit: what we can learn from their mistakes

Fruit foragers are known to use spatial memory to relocate fruit, yet it is unclear how they manage to find fruit in the first place. In this study, we investigated whether chimpanzees (Pan troglodytes verus) in the Taï National Park make use of fruiting synchrony, the simultaneous emergence of fruit in trees of the same species, which can be used together with sensory cues, such as sight and smell, to discover fruit. We conducted observations of inspections, the visual checking of fruit availability in trees, and focused our analyses on inspections of empty trees, so to say “mistakes”. Learning from their “mistakes”, we found that chimpanzees had expectations of finding fruit days before feeding on it and significantly increased inspection activity after tasting the first fruit. Neither the duration of feeding nor density of fruit-bearing trees in the territory could account for the variation in inspection activity, which suggests chimpanzees did not simply develop a taste for specific fruit on which they had fed frequently. Instead, inspection activity was predicted by a botanical feature—the level of synchrony in fruit production of encountered trees. We conclude that chimpanzees make use of the synchronous emergence of rainforest fruits during daily foraging and base their expectations of finding fruit on a combination of botanical knowledge founded on the success rates of fruit discovery, and a categorization of fruit species. Our results provide new insights into the variety of food-finding strategies employed by primates and the adaptive value of categorization capacities.     

Development and evaluation of the psychometric properties of the parents' Perceptions of Physical Activity Importance and their Children's Ability Questionnaire (PPPAICAQ)

ObjectivesThe purpose of the present study was to develop and psychometrically evaluate a new measure of parental perceptions grounded in the Eccles' parental socialization framework: the Parents' Perceptions of Physical Activity Importance and their Children's Ability Questionnaire (PPPAICAQ).DesignCross-sectional with self-reported questionnaires.MethodThe total sample comprised 1100 parents of children (6–11 years old) and was randomly divided in third (one calibration and two validation samples). Data were analyzed with reliability, confirmatory factor analyses (CFA), multi-group CFAs as well as with correlational analyses.ResultsResults of the initial confirmatory factor analyses (CFAs) of the 2-factor 12-item model on the calibration sample resulted in a poor fit to the data. Re-estimation of the PPPAICAQ resulted in the deletion of 4 initial items. The 2-factor 8-item model revealed a good fit to the data for the three samples. Results of two multiple-group CFAs showed that the final model was partially invariant across the father and mother as well as the boy and girl samples. The patterns of relationships between parents' motivation, parents' support and the PPPAICAQ subscales provided evidence for the criterion-related validity of the PPPAICAQ.ConclusionThis study provided support for the reliability and validity of the PPPAICAQ. The PPPAICAQ is an instrument that will be useful for theoretically-driven research on parental socialization influence on children’ PA.     

When do people cooperate? The neuroeconomics of prosocial decision making

Understanding the roots of prosocial behavior is an interdisciplinary research endeavor that has generated an abundance of empirical data across many disciplines. This review integrates research findings from different fields into a novel theoretical framework that can account for when prosocial behavior is likely to occur. Specifically, we propose that the motivation to cooperate (or not), generated by the reward system in the brain (extending from the striatum to the ventromedial prefrontal cortex), is modulated by two neural networks: a cognitive control system (centered on the lateral prefrontal cortex) that processes extrinsic cooperative incentives, and/or a social cognition system (including the temporo-parietal junction, the medial prefrontal cortex and the amygdala) that processes trust and/or threat signals. The independent modulatory influence of incentives and trust on the decision to cooperate is substantiated by a growing body of neuroimaging data and reconciles the apparent paradox between economic versus social rationality in the literature, suggesting that we are in fact wired for both. Furthermore, the theoretical framework can account for substantial behavioral heterogeneity in prosocial behavior. Based on the existing data, we postulate that self-regarding individuals (who are more likely to adopt an economically rational strategy) are more responsive to extrinsic cooperative incentives and therefore rely relatively more on cognitive control to make (un)cooperative decisions, whereas other-regarding individuals (who are more likely to adopt a socially rational strategy) are more sensitive to trust signals to avoid betrayal and recruit relatively more brain activity in the social cognition system. Several additional hypotheses with respect to the neural roots of social preferences are derived from the model and suggested for future research.     

Do self‐presentation concerns moderate the relationship between implicit and explicit homonegativity measures?

This study investigated whether the relation between implicit and explicit homonegativity measures is affected by self-presentation concerns, since previous research in this area has been inconclusive. In Experiment 1, 70 high-school students made evaluative ratings of pictures of homosexual and heterosexual couples. Self-presentation was manipulated by either instructing participants that the study concerned attitudes regarding sexual orientation (socially sensitive) or attitudes regarding age (less sensitive). The age-instruction led to increased homonegativity but not to a stronger correlation with an Implicit Association Test (IAT; Greenwald, McGhee & Schwartz, 1998) with homo/heterosexual couples. Concerns regarding the construct validity of the present implementation of the IAT were alleviated in Experiment 2, where heterosexual (n= 30) but not homosexual (n= 30) participants showed implicit homonegativity. The current findings are problematic for the interpretation of low correspondence between implicit and explicit attitude measures as being primarily an effect of self-presentation concerns.     

Comparing the EthoVision 2.3 system and a new computerized multitracking prototype system to measure the swimming behavior in fry fish

Coming from the framework of unmarked fry tracking, we compared the capacities, advantages, and disadvantages of two recent video tracking systems: EthoVision 2.3 and a new prototype of multitracking. The EthoVision system has proved to be impressive for tracking a fry using the detection by gray scaling. Detection by subtraction has given less accurate results. Our video multitracking system is able to detect and track more than 100 unmarked fish by gray scaling technique. It permits an analysis at the group level as well as at the individual level. The multitracking program is able to attribute a number to each fish and to follow each one for the whole duration of the track. Our system permits the analysis of the movement of each individual, even if the trajectories of two fish cross each other. This is possible thanks to the theoretical estimation of the trajectory of each fish, which can be compared with the real trajectory (analysis with feedback). However, the period of the track is limited for our system (about 1 min), whereas EthoVision is able to track for numerous hours. In spite of these limitations, these two systems allow an almost continuous automatic sampling of the movement behaviors during the track.