Goal congruency in bimanual object manipulation

In 3 experiments, the authors investigated the impact of action goals on the production of discrete bimanual responses. Similar to a bartender putting 2 glasses simultaneously on a shelf, participants placed 2 objects into either parallel or opposite orientations by carrying out either mirror-symmetrical or mirror-asymmetrical movements. In Experiment 1, performance was strongly affected by the congruency of the intended object orientations but was essentially unaffected by movement symmetry. Experiment 2 replicated this instrumental goal-congruency effect (and the absence of motor-symmetry effects) when actions were cued in advance. Experiment 3 revealed substantial motor-symmetry effects, provided the movements themselves became the action goal. The authors concluded that performance in bimanual choice reaction tasks is constrained by the creation and maintenance of goal codes rather than by properties inherent in the neuromuscular system that carries out these responses. These goals can relate to either body-intrinsic states or to body-extrinsic states according to the actor's current intentions.     

APP23 mice as a model of Alzheimer's disease: an example of a transgenic approach to modeling a CNS disorder

Animal models are considered essential in research ensuing elucidation of human disease processes and subsequently, testing of potential therapeutic strategies. This is especially true for neurodegenerative disorders, in which the first steps in pathogenesis are often not accessible in human patients. Alzheimer's disease is vastly becoming a major medical and socioeconomic problem in our aging society. Valid animal models for this uniquely human condition should exhibit histopathological, biochemical, cognitive, and behavioral alterations observed in Alzheimer's disease patients. Major progress has been made since the understanding of the genetic basis of Alzheimer's disease and the development and improvement of transgenic mouse models. All present Alzheimer's disease models developed are partial but nevertheless essential in further unraveling the nature and spatial and temporal development of the complex molecular pathology underlying this condition. One of the more recent transgenic attempts to model Alzheimer's disease is the APP23 transgenic mouse. This article describes the development and assessment of this human amyloid precursor protein overexpression model. We summarize histopathological and biochemical, cognitive and behavioral observations made in heterozygous APP23 mice, thereby emphasizing the model's contribution to clarification of neurodegenerative disease mechanisms. In addition, the first therapeutic interventions in the APP23 model are included.     

Memory accessibility, mood regulation, and dysphoria: difficulties in repairing sad mood with happy memories?

Recent studies have suggested that mood-incongruency effects are due to mood-regulatory processes, in which people retrieve positive memories to repair negative moods. In Study 1, the authors investigated whether dysphoria influences the accessibility of autobiographical memories following a positive or a negative mood induction combined with subsequent rumination or distraction. The results showed a mood-repair effect for nondysphoric but not for dysphoric participants following rumination. In Study 2, participants were asked to either distract themselves or to recall positive autobiographical memories after a negative mood induction. Whereas nondysphoric participants' mood improved under both conditions, dysphoric participants' mood improved only after distraction. These results suggest that dysphoria is associated with a reduced ability to use mood-incongruent recall to repair sad moods.     

Decision-making impairments in patients with Parkinson's disease

A high percentage of Parkinson's disease (PD) patients show cognitive impairments in addition to the cardinal motor symptoms. These deficits primarily concern executive functions most probably linked to dysfunctions in prefrontal regions due to decreased dopaminergic transmission in fronto-striatal loops. To investigate possible associations between decision-making and executive functions in PD, we examined 20 non-demented PD patients and 20 healthy control subjects with a neuropsychological test battery and the Game of Dice Task. In this computerised decision-making task, the rules for gains and losses and the winning probabilities are obvious and stable. Thus, strategic components besides feedback processing might influence decision-making in this task. We found that PD patients were impaired in the Game of Dice task performance and that the frequency of disadvantageous choices correlated with both executive functions and feedback processing. We suggest that decision-making deficits of PD patients in explicit gambling situations might be associated with dysfunctions in two different fronto-striatal loops: the limbic-orbitofrontal-striatal loop, involved in feedback processing, and the dorsolateral prefrontal-striatal loop, involved in executive functions.     

DRG-Vergütung und Kosten stationärer integrierter psychosomatischer Behandlung

Ohne ZusammenfassungDie Autoren M. Rose und R. Lohmann zeichnen für den Beitrag als gleichberechtigte Erstautoren.     

"Capacity" reconsidered: interindividual differences in language comprehension and individual alpha frequency

The influence of interindividual differences in cognitive mechanisms on language comprehension remains controversial not only due to conflicting experimental findings, but also in view of the difficulty associated with determining which measure should be used in participant classification. Here, we address the latter problem by proposing that an electrophysiological measure, individual alpha frequency (IAF), may be a suitable means of classifying interindividual differences in sentence processing. Interindividual differences in IAF have been shown to correlate with performance on memory tasks and speed of information processing. In two experiments using event-related brain potentials (ERPs), IAF-based participant groups differed systematically with regard to the processing of ambiguous sentences such that the low-IAF group showed a sustained positivity in the ambiguous region, while the high-IAF group did not. These interindividual differences were independent of whether the ambiguity was syntactic (Experiment 1) or sentence-level semantic (Experiment 2). Moreover, they were reliable only when participants were classified according to IAF, but not in classifications based on reading span, speed of processing (reaction time), or accuracy of processing (error rate).     

A person-fit index for polytomous rasch models,latent class models,and their mixture generalizations

A normally distributed person-fit index is proposed for detecting aberrant response patterns in latent class models and mixture distribution IRT models for dichotomous and polytomous data.This article extends previous work on the null distribution of person-fit indices for the dichotomous Rasch model to a number of models for categorical data. A comparison of two different approaches to handle the skewness of the person-fit index distribution is included.Major parts of this paper were written while the first author worked at the Institute for Science Education, Kiel, Germany. Any opinions expressed in this paper are those of the authors and not necessarily of Educational Testing Service. The results presented in this paper were improved by valuable comments from J. Rost, K. Yamamoto, N.D. Verhelst, E. Bedrick and two anonymous reviewers.     

The social dynamics of a cultural upheaval: social interactions surrounding September 11, 2001

Using the Electronically Activated Recorder (EAR), a new methodology for sampling behavioral data in naturalistic settings, we tracked the social lives of 11 people by recording 30-s snippets of ambient sounds in their environment approximately every 12 min. Participants wore the EAR continuously for 10 days from September 11, 2001. Pre-September 11 baseline data were available for all participants. Analyses of the coded sound information showed that although participants did not change in their overall amount of interactions, they gradually shifted from group conversations to dyadic interactions. Exploratory analyses revealed that a relative increase in dyadic interactions over the first 10 days after September 11 was marginally related to better psychological adjustment at follow-up. The findings have relevance for the understanding of stress and affiliation and normal psychological reactions to emergencies.     

Causal Warrant for Realism about Particle Physics

While scientific realism generally assumes that successful scientific explanations yield information about reality, realists also have to admit that not all information acquired in this way is equally well warranted. Some versions of scientific realism do this by saying that explanatory posits with which we have established some kind of causal contact are better warranted than those that merely appear in theoretical hypotheses. I first explicate this distinction by considering some general criteria that permit us to distinguish causal warrant from theoretical warrant. I then apply these criteria to a specific case from particle physics, claiming that scientific realism has to incorporate the distinction between causal and theoretical warrant if it is to be an adequate stance in the philosophy of particle physics.