Cognitive impairments in the STOP null mouse model of schizophrenia.

Cognitive dysfunction is a primary and persisting core deficit of schizophrenia that is marginally improved by antipsychotic treatment. Adult mice that lack the stable tubule-only polypeptide (STOP) have neurochemical and behavioral abnormalities that model some features of schizophrenia. Recognition and long-term memory in the STOP null mouse were tested with the novel object recognition task and an olfactory discrimination task, respectively. Researchers examined the brains from STOP null mice to determine whether differences in task performance were associated with alterations in brain morphology. STOP null mice displayed deficits in both recognition and long-term memory. These behavioral deficits were accompanied by a massive enlargement of the cerebral ventricular system as well as by reductions in volume of cortical and diencephalic structures. In addition to deficits in recognition and long-term memory, STOP null mice displayed exaggerated neuroanatomical deficits somewhat reminiscent of those observed among individuals with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Altered performance of reelin-receptor ApoER2 deficient mice on spatial tasks using the Barnes maze.

The apolipoprotein E receptor 2 (ApoER2), expressed predominantly in forebrain regions including the hippocampus, is 1 of 2 receptors for the extracellular matrix protein reelin, which is critical for cortical development. Previous studies of ApoER2 mutant mice have indicated deficits in synaptic plasticity and learning. The current authors assessed learning and memory of ApoER2 knockout and wild-type mice on the Barnes circular maze. Mice were trained in this task for 22 days, followed by memory recall and reversal tests. ApoER2 knockout mice were initially slower to complete the task, but by Day 22 they were more accurate than wild-type mice on several indices. There were no differences in memory assessed by the recall task, but ApoER2 knockout mice performed significantly worse on the memory reversal task. ApoER2 knockout mice also displayed altered use of specific search strategies and relationship of these strategies to errors made on the maze. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Asking research participants about trauma and abuse.

Comments on the article by K. Becker-Blease and J. Freyd (see record 2006-03947-003), which presented a timely, persuasive, and well-documented argument to psychologists about why it is important to consider asking about a history of abuse and/or trauma in research studies. As a social psychologist studying victims' disclosures of sexual assault, social reactions received from others following disclosure, and the effects of these reactions on victims, S. E. Ullman expands on just a few of the 10 concerns discussed in their article regarding risks associated with trauma and abuse disclosure that may help researchers decide about whether to ask such questions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of suicide risk in a psychiatric hospital.

Assessment of suicide risk is a serious responsibility of psychologists. Best practice instructs use of a standardized instrument and clinical interview to evaluate suicide risk. Six instruments used to assess suicide behavior and symptoms of anxiety and depression were examined. The sample was adults receiving acute psychiatric treatment in a public hospital. The study consisted of 2 groups: 25 patients admitted for suicidal behavior and 42 patients admitted for other reasons. Analyses were conducted to discriminate between the 2 groups on study instruments. No single instrument predicted suicide risk without significant error. Standardized assessments must be used as part of a structured clinical interview. Suicide risk should be assessed with all people admitted to the hospital regardless of admissions criteria. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do induced moods really influence health perceptions?

Objective. To determine whether induced mood alters health reports. Design. Randomized experiments testing a) mood influence on two global self-rated health (SRH) assessments (Study 1; N = 168) and b) testing whether illness relevant thinking moderates the influence of induced negative mood on SRH and physical symptom reports (Study 2; N = 143). Main Outcome Measures. Two global SRH items. Results. Effect sizes for induced mood were near zero across both studies (r's = 0.00-0.07). Aggregate analyses of induced mood studies showed a small adverse effect of induced negative mood on SRH, but these analyses masked roughly equal instances of better SRH among groups with worse mood. Conclusion. Published experimental research shows no consistent pattern of poorer SRH following negative mood induction in college-aged samples. Sample size and gender may account for variation in health ratings among induced mood groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Process components of the Implicit Association Test: A diffusion-model analysis.

The authors present a diffusion-model analysis of the Implicit Association Test (IAT). In Study 1, the IAT effect was decomposed into 3 dissociable components: Relative to the compatible phase, (a) ease and speed of information accumulation are lowered in the incompatible phase, (b) more cautious speed-accuracy settings are adopted, and (c) nondecision components of processing require more time. Studies 2 and 3 assessed the nature of interindividual differences in these components. Construct-specific variance in the IAT relating to the construct to be measured (such as implicit attitudes) was concentrated in the compatibility effect on information accumulation (Studies 2 and 3), whereas systematic method variance in the IAT was mapped on differential speed-accuracy settings (Study 3). Implications of these dissociations for process theories of the IAT and for applications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of 2D and 3D representations for visualising telecommunication usage

This paper describes an empirical evaluation of one two-dimensional (2D), and two three-dimensional (3D) representations. These representations were developed to present customer behaviour information on telecommunications usage. The goal of the study was to investigate how the properties of these different but informationally equivalent representations supported information retrieval and problem solving using the database. Thirty-six participants performed a number of information retrieval and problem solving tasks, in one of three experimental conditions: 2D graph, 3D graph and 3D helix plot. Measures included performance time and accuracy and user attitudes concerning the usability of the displays. Despite certain navigational problems associated with the 2D representation, the results indicated a performance advantage for the 2D display compared with both 3D representations. Generally, the analyses revealed that the differences in representational characteristics have a significant effect on the level of cognitive effort required to perform the tasks.     

P50 suppression in recent-onset schizophrenia: Clinical correlates and risperidone effects.

Chronic schizophrenic patients often do not suppress the auditory P50 component of the event-related potential to the second of 2 clicks, presented 500 ms apart, suggesting a loss of normal inhibition. This study attempted to replicate the P50 suppression deficit in patients with recent-onset schizophrenia and to examine whether P50 is related to clinical symptoms or is affected by an atypical antipsychotic medication. Data from 22 recent-onset schizophrenia patients and 11 normal controls revealed that disruption in P50 suppression is present during the early stages of illness. In addition, impaired P50 suppression covaried with clinical ratings of anxiety, depression, and anergia; results also suggested that the P50 inhibitory deficit may be related to the degree of patients' attentional impairment. Finally, risperidone, compared with a typical antipsychotic medication, improved inhibition of P50 to the second click. These results support P50 suppression as a measure of disordered neurocognition in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of perinatal hypoxic risk on developmental outcome in early and middle childhood: A twin study.

The goal of this study of 66 twins was to determine whether motor and cognitive functions assessed in early and middle childhood are vulnerable to perinatal hypoxic risk. In an earlier study of 76 infant and toddler twins (S. Raz, F. Shah, & C. Sander, 1996), the authors found that intrapair discrepancy on the Mental Developmental Index, but not on the Psychomotor Developmental Index, of the Bayley Scales of Infant Development was associated with discordance for perinatal hypoxic risk. The twins at lower risk outperformed their higher risk co-twins. In the present study the authors sought to establish in a new sample of preschool and school-age twins whether gaps in performance persist into early and middle childhood. Although the disparity in hypoxic risk between the co-twins was typically moderate, significant intrapair differences were observed on the measure of motor performance. Among the motor abilities examined, skills involving visually guided ballistic arm movements appeared to be the most vulnerable to perinatal risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)