Amygdala or hippocampus inactivation after retrieval induces temporary memory deficit

The hypothesis that memory is stored through a single stage of consolidation that results in a stable and lasting long-term memory has been challenged by the proposition that reactivation of a memory induces reconsolidation of the memory. The reconsolidation hypothesis is supported by evidence that, under some conditions, post-retrieval treatments affecting amygdala and hippocampus functioning impair subsequent retention performance. We now report that repeated retention testing attenuates the performance impairment induced by post-retrieval reversible inactivation of the amygdala and hippocampus of rats induced by tetrodotoxin. These findings challenge the reconsolidation hypothesis and suggest that the post-retrieval retention performance impairment is best explained as due to temporary retrieval failure.     

Differential developmental trajectories for egocentric, environmental and intrinsic frames of reference in spatial memory

We studied the development of spatial frames of reference in children aged 3-6 years, who retrieved hidden toys from an array of identical containers bordered by landmarks under four conditions. By moving the child and/or the array between presentation and test, we varied the consistency of the hidden toy with (i) the body, and (ii) the testing room. The toy's position always remained consistent with (iii) the array and bordering landmarks. We found separate, additive performance advantages for consistency with body and room. These effects were already present at 3 years. A striking finding was that the room effect, which implies allocentric representations of the room and/or egocentric representations updated by self-motion, was much stronger in the youngest children than the body effect, which implies purely egocentric representations. Children as young as 3 years therefore had, and greatly favoured, spatial representations that were not purely egocentric. Viewpoint-independent recall based only on the array and bordering landmarks emerged at 5 years. There was no evidence that this later-developing ability, which implies object-referenced (intrinsic) representations, depended on verbal encodings. These findings indicate that core components of adult spatial competence, including parallel egocentric and nonegocentric representations of space, are present as early as 3 years. These are supplemented by later-developing object-referenced representations.     

The Solvability of Probabilistic Regresses. A Reply to Frederik Herzberg

We have earlier shown by construction that a proposition can have a welldefined nonzero probability, even if it is justified by an infinite probabilistic regress. We thought this to be an adequate rebuttal of foundationalist claims that probabilistic regresses must lead either to an indeterminate, or to a determinate but zero probability. In a comment, Frederik Herzberg has argued that our counterexamples are of a special kind, being what he calls ‘solvable’. In the present reaction we investigate what Herzberg means by solvability. We discuss the advantages and disadvantages of making solvability a sine qua non, and we ventilate our misgivings about Herzberg’s suggestion that the notion of solvability might help the foundationalist.     

Applying Multiple Knowledge Structures in Creative Thought: Effects on Idea Generation and Problem-Solving

Prior studies have indicated that multiple knowledge structures, schema, associations, and cases, are involved in creative thought. Few studies, however, have examined how these different knowledge structures operate together in idea generation and creative problem-solving. Accordingly, in the present study 247 undergraduates were asked to generate ideas relevant to a social innovation problem and then provide a potential solution to the problem. A training manipulation was used to encourage application of schematic, associational, or case-based knowledge either alone or in combination. It was found that prompting use of a single knowledge structure, specifically schema or associational knowledge, resulted in the production of more high quality ideas. However, prompting use of multiple knowledge structures, specifically combining either schema or associations with cases, resulted in the production of higher quality and more original problem-solutions. The implications of these findings for understanding the role of different knowledge structures in creative thought are discussed.     

In search of average growth: Describing within-year oral reading fluency growth across Grades 1–8

Measures of oral reading fluency (ORF) are perhaps the most often used assessment to monitor student progress as part of a response to intervention (RTI) model. Rates of growth in research and aim lines in practice are used to characterize student growth; in either case, growth is generally defined as linear, increasing at a constant rate. Recent research suggests ORF growth follows a nonlinear trajectory, but limitations related to the datasets used in such studies, composed of only three testing occasions, curtails their ability to examine the true functional form of ORF growth. The purpose of this study was to model within-year ORF growth using up to eight testing occasions for 1448 students in Grades 1 to 8 to assess (a) the average growth trajectory for within-year ORF growth, (b) whether students vary significantly in within-year ORF growth, and (c) the extent to which findings are consistent across grades. Results demonstrated that for Grades 1 to 7, a quadratic growth model fit better than either linear or cubic growth models, and for Grade 8, there was no substantial, stable growth. Findings suggest that the expectation for linear growth currently used in practice may be unrealistic.     

Beyond Components of Wellbeing: The Effects of Relational and Situated Assemblage

Despite multiple axes of variation in defining wellbeing, the paper argues for the dominance of a ‘components approach’ in current research and practice. This approach builds on a well-established tradition within the social sciences of attending to categories whether for their identification, their value or their meanings and political resonance. The paper critiques the components approach and explores how to move beyond it towards conceptually integrating the various categories and dimensions through a relational and situated account of wellbeing. Drawing on more fluid social sciences, wellbeing is framed as an effect, dependent on the mobilisation of resources from everyday encounters with complex assemblages of people, things and places. Through such a framing, wellbeing can be conceived of as stable and amenable to change, as individual and collective and as subjective and objective. Policy interventions then need to attend to the relationalities of particular social and spatial contexts.     

The Relationship Between Childhood Trauma,Combat Exposure,and Posttraumatic Stress Disorder in Male Veterans

The current study investigated the effects of combat exposure, childhood trauma, and depression on posttraumatic stress disorder (PTSD) severity. Participants were 299 male veterans from the Korean War, World War II, Vietnam, and the first Gulf War who were being screened for admission to the PTSD unit. Participants were assessed with the Clinician-Administered PTSD Scale (CAPS), Combat Exposure Scale (CES), Hamilton Depression Rating Scale (HAMD), Childhood Trauma Questionnaire (CTQ), and Mississippi Scale for PTSD (MPTSD). Results of multiple regression analyses indicated that, as expected, combat exposure and depression were significant predictors of PTSD severity. When examined with combat exposure, childhood trauma has a complex relationship to PTSD severity. Examination of the interaction between the CES and CTQ suggests that when levels of combat are low and childhood trauma levels are high, the CTQ is related to higher levels of PTSD severity on the CAPS, regardless of depression. Treatment implications are discussed.     

Quality adjusted survival analysis: A neglected application of the quality of well-being scale

Abstract

Background In survival analysis, those who are alive are statistically coded as 1.0 while those who are dead are coded as 0.0. Since everyone who remains alive is given the same score, a person confined to bed with an irreversible coma is alive and is counted the same as someone who is active and asymtomatic. The Quality of Well-being (QWB) scale defines levels of wellness on the continuum between death and optimum function and integrates morbidity and mortality into the same number. This paper demonstrates the effect of including mortality in QWB estimates for male adults with HIV infection.

Method This study involves follow-up of a cohort of 386 male adults participating in the San Diego HIV Neurobehavioral Research Center (HNRC). Patients were evaluated using the QWB at enrollment and at six month intervals. All patients were classified into three stages of HIV disease according to the Center for Disease Control (CDC) classification: CDC IV (symptomatic HIV disease), CDC II or III (asymptomatic infection) and uninfected male controls.

Results QWB scores were calculated with and without mortality included for men in each CDC class who completed a one year (N = 148) or two year follow-up (N = 60). At each evaluation, there were significant differences among CDC classes and inclusion of deaths increased the variance accounted for by CDC class at each evaluation.

Conclusions HIV infection has significant impacts upon both morbidity and mortality. Survival analysis captures only the mortality dimension, while quality adjusted survival analysis using the QWB includes both dimensions. We propose quality adjusted survival analysis as a more sensitive method for assessing outcome in HIV disease and other health conditions.