Changes in the neuropsychological correlates of clinical dimensions between the acute and stable phase of schizophrenia

This study was designed to investigate whether the neuropsychological correlates of the symptom dimensions of schizophrenia vary with the clinical state in patients followed from the acute to stable the phase of the illness. Fifteen patients were assessed for symptoms (SAPS-SANS) and undergone a complete neuropsychological assessment at two sessions. The first session (S1) was carried out within six days after admission, i.e., acute phase and the second (S2) at least two month after hospitalization, i.e., stable phase. The data were analyzed using stepwise regression models in which neuropsychological scores were in entered to predict each dimensional score. This analysis was applied on the S1 and S2 data as well as on the S2-S1 difference to assess the neuropsychological predictors of clinical changes. Generally, the results replicate the previous associations between neuropsychological and dimensional measures found in stable patients. In addition, this study shows if each dimension appears to rely on a key structure, symptom variations seems to involve changes in the spread of the dysfunction and/or changes in the connectivity between the key and other regions. The results also suggest that functional changes related to some symptoms dimensions occur to compensate for the dysfunction associated with other symptoms.     

Development and validation of a brief version of the dyadic adjustment scale with a nonparametric item analysis model

The main purpose of the current research was to develop an abbreviated form of the Dyadic Adjustment Scale (DAS) with nonparametric item response theory. The authors conducted 5 studies, with a total participation of 8,256 married or cohabiting individuals. Results showed that the item characteristic curves behaved in a monotonically increasing function for all items of the brief 4-item version of the DAS (DAS-4). The DAS-4 proved to be informative at all levels of couple satisfaction. Compared with the 32-item version of the DAS (DAS-32), it was as effective in predicting couple dissolution and was significantly less contaminated by socially desirable responding. In addition, structural equation modeling demonstrated that the underlying latent construct measured by the DAS-4 was very stable over a 2-year period. This brief version has the advantage of being less time consuming and constitutes a promising alternative to the original DAS-32 for clinicians and researchers.     

Cytokine production by spleen cells after social defeat in mice: activation of T cells and reduced inhibition by glucocorticoids

Social disruption (SDR) is an effective model of social stress associated with an enhanced inflammatory reactivity of the immune system. The aim of the present study was to further describe SDR effects on cytokine production by spleen cells, testing selectively monocyte and T cell functions as a result of this stressor. For this purpose, splenocytes from control mice (C) and mice socially stressed for 7 days (SDR) were cultured in the presence of lipopolysaccharide (LPS) or concanavalin A (Con A). Splenocyte proliferation, cytokine production and sensitivity of spleen cells to corticosterone were assessed in vitro. The humoral response to keyhole limpet hemocyanin (KLH) immunization was assessed. SDR induced splenomegaly and enhanced splenocyte basal proliferation. The pro-inflammatory influence of SDR was confirmed by an increased release of interleukin-6 (IL-6) by LPS-stimulated cultures and by a reduced sensitivity of spleen cells to the anti-inflammatory effect of corticosterone. The mechanism increasing cytokine production in response to LPS was cytokine specific, since among inflammatory cytokines, IL-6 but not interferon-gamma (IFN-gamma) was enhanced by stress. In stressed mice, the increase in IL-6 and IFN-gamma and the decrease in IL-10 release in Con A-stimulated cultures indicate that SDR did not modify the Th1/Th2 cytokine balance but globally activated T cells. Plasma anti-KLH antibody levels were similar in both groups. Wounded and non-wounded mice presented similar responses to stress. This study shows that social disruption stress enhances the reactivity of cells from both the acquired and innate immune systems.     

Changing features do not guide attention in change detection: Evidence from a spatial cuing paradigm

Smilek, Eastwood, and Merikle (2000) demonstrated that the detection of change was facilitated when the target character changed in many rather than few of its features. Specifically, the function relating search response time to display set size was shallower when more features changed than when fewer features changed. The researchers interpreted these results as indicating that large feature changes provide preattentive guidance of focal attention to the location of the change. We tested this preattentive guidance hypothesis by examining change detection performance in the context of a spatial cuing paradigm. The hypothesis predicts that (1) the cost on invalidly cued trials should be less when more features change than when fewer features change, and (2) the features manipulation should have no effect on validly cued trials. In contrast to these predictions, our results show that cuing effects are equivalent across all levels of feature change and that a robust effect of the features manipulation is observable for both validly and invalidly cued trials. We argue that large feature changes do not provide preattentive guidance and in fact can be detected more readilyafter attention is already in place at the target location.     

Repetition blindness: out of sight or out of mind?

Does repetition blindness represent a failure of perception or of memory? In Experiment 1, participants viewed rapid serial visual presentation (RSVP) sentences. When critical words (C1 and C2) were orthographically similar, C2 was frequently omitted from serial report; however, repetition priming for C2 on a postsentence lexical decision task was equivalent whether or not C1 was similar to C2. In Experiment 2, participants monitored RSVP sentences for a predetermined target. Participants frequently failed to detect the target when it was preceded by an orthographically similar word. In Experiment 3, the authors investigated the role of the attentional blink in this effect. These experiments suggest that repetition blindness is a failure of conscious perception, consistent with predictions of the token-individuation hypothesis.     

Virtually no evidence for virtually perfect time-sharing

An examination of previous claims for virtually perfect time-sharing in dual-task situations reveals confounding effects that may have obscured dual-task interference. Two experiments are conducted in which these confounding effects are minimized, revealing statistically significant dual-task interference. These results support the hypothesis that human information processing is dominated by a structural central capacity limitation and call into question the hypothesis that dual-task interference can be eliminated by meeting the 5 conditions outlined by D. Meyer and D. Kieras (1999).     

Arguments for adjuncts

It is commonly assumed across the language sciences that some semantic participant information is lexically encoded in the representation of verbs and some is not. In this paper, we propose that semantic obligatoriness and verb class specificity are criteria which influence whether semantic information is lexically encoded. We present a comprehensive survey of the English verbal lexicon, a sentence continuation study, and an on-line sentence processing study which confirm that both factors play a role in the lexical encoding of participant information.     

Using video modeling and reinforcement to teach perspective-taking skills to children with autism

We evaluated video modeling and reinforcement for teaching perspective-taking skills to 3 children with autism using a multiple baseline design. Video modeling and reinforcement were effective; however, only 2 children were able to pass an untrained task, indicating limited generalization. The findings suggest that video modeling may be an effective technology for teaching perspective taking if researchers can continue to develop strategies for enhancing the generalization of these new skills.     

A central capacity sharing model of dual-task performance

The authors present the central capacity sharing (CCS) model and derive equations describing its behaviors to explain results from dual-task situations. The predictions of the CCS model are contrasted with those of the central bottleneck model. The CCS model predicts all of the hallmark effects of the psychological refractory period (PRP) pardigm: -1 slope of the PRP effect at short stimulus onset asynchronies (SOAs), underadditivity of precentral Task 2 manipulations, additivity of central or postcentral Task 2 manipulations with SOA, and carry forward to Task 2 of Task 1 precentral or central manipulations at short SOAs. The CCS model also predicts that Task 1 response times increase with decreasing SOA. The model is a viable alternative to the central bottleneck model.