Rigidity in social and emotional memory in the R6/2 mouse model of Huntington's disease

Four experiments were conducted to examine social and emotional memory in the R6/2 transgenic mouse model of Huntington’s disease. First, R6/2 mice were tested in a social transmission of food preference task where they had to acquire a preference for a flavoured food (acquisition) and subsequently to learn a preference for a different flavour (shifted reinforcement). R6/2 mice performed well in the acquisition trial. However, they were impaired in the shifted reinforcement trial and perseverated on the first preference learned. Second, mice were trained in an inhibitory avoidance paradigm, with either one or two footshocks delivered during the training. WT mice given one footshock showed retention levels lower than those of mice trained with two footshocks. By contrast, there was no difference in retention levels of R6/2 mice given either one or two footshocks. Third, mice were tested in an active avoidance task that paired a mild footshock with a warning light. R6/2 mice had a strong age-dependent deficit in this task. Finally, mice were tested in a conditioned taste aversion task that paired a saccharine solution with a nausea-inducing agent (LiCl). R6/2 mice displayed normal aversion, however this was not extinguished following repeated exposure to saccharine solution alone. Our data show that while R6/2 mice have functional hippocampus-based memory, they have deficits in striatum-based memory skills. Further, social and emotional memories appear to be encoded in a rigid way that is not influenced by subsequent learning or by arousal levels.     

Component Models for Fuzzy Data

The fuzzy perspective in statistical analysis is first illustrated with reference to the “Informational Paradigm” allowing us to deal with different types of uncertainties related to the various informational ingredients (data, model, assumptions). The fuzzy empirical data are then introduced, referring to J LR fuzzy variables as observed on I observation units. Each observation is characterized by its center and its left and right spreads (LR₁ fuzzy number) or by its left and right “centers” and its left and right spreads (LR₂ fuzzy number). Two types of component models for LR₁ and LR₂ fuzzy data are proposed. The estimation of the parameters of these models is based on a Least Squares approach, exploiting an appropriately introduced distance measure for fuzzy data. A simulation study is carried out in order to assess the efficacy of the suggested models as compared with traditional Principal Component Analysis on the centers and with existing methods for fuzzy and interval valued data. An application to real fuzzy data is finally performed. We would like to express our gratitude to the Editor, the Associate Editor, and the Referees whose comments and suggestions improved significantly the quality of the paper.     

Neuroscience today,Florence 25–27 March 2007: foreword

Currently in humor research, there exists a dearth of computational models for humor perception. The existing theories are not quantifiable and efforts need to be made to quantify the models and incorporate neuropsychological findings in humor research. We propose a new computational model (GraPHIA) for perceiving phonological jokes or puns. GraPHIA consists of a semantic network and a phonological network where words are represented by nodes in both the networks. Novel features based on graph theoretical concepts are proposed and computed for the identification of homophonic jokes. The data set for evaluating the model consisted of homophonic puns, normal sentences, and ambiguous nonsense sentences. The classification results show that the feature values result in successful identification of phonological jokes and ambiguous nonsense sentences suggesting that the proposed model is a plausible model for humor perception. Further work is needed to extend the model for identification of other types of phonological jokes.

Cueing the interpretation of a Necker Cube: a way to inspect fundamental cognitive processes

The term perceptual bistability refers to all those conditions in which an observer looks at an ambiguous stimulus that can have two or more distinct but equally reliable interpretations. In this work, we investigate perception of Necker Cube in which bistability consists of the possibility to interpret the cube depth in two different ways. We manipulated the cube ambiguity by darkening one of the cube faces (cue) to provide a clear cube interpretation due to the occlusion depth index. When the position of the cue is stationary the cube perceived perspective is steady and driven by the cue position. However, when we alternated in time the cue position (i.e. we changed the position of the darkened cube face) two different perceptual phenomena occurred: for low frequencies the cube perspective alternated in line with the position of the cue; however for high frequencies the cue was no longer able to bias the perception but it appears as a floating feature traveling across the solid with the cube whole perspective that returns to be bistable as in the conventional, bias-free, case.     

Computerized cognitive training during physical inactivity improves executive functioning in older adults

The hippocampus is closely tied to spatial navigation, a central component in cognitive functioning, and critically involved in age-associated cognitive decline and dementia. This study evaluated a novel, cognitive computerized spatial navigation training (CSNT) program targeting the hippocampus, with expectation of mitigating possible cognitive decline with bed rest (BR). During a 14-day BR study with 16 healthy, older men (mean age = 60 ± 3, range = 55–65 years), half received CSNT for 12 days in 50-min sessions and half were controls (watching documentaries). This design uniquely controlled diet, sleep, and other personal and environmental activities. Although there were no cognitive declines in controls post-BR, CSNT participants demonstrated significant increases in executive/attention ability and processing speed, and continued spatial navigation testing showed improvement to 400 days post-BR. This intervention may prove useful to mitigate cognitive declines known to occur in long periods of immobilization and could have broader implications in protecting against age-related cognitive decline.     

Short-term effects of a multi-disciplinary cardiac rehabilitation programme on psychological well-being, exercise capacity and weight in a sample of obese in-patients with coronary heart disease: a practice-level study

Given that many patients referred to cardiac rehabilitation (CR) are obese, diet therapy, exercise training, nutritional and psychological counselling for both obesity and psychological distress should be included as important components in all CR programmes. In this practice-level, observational study we evaluated the short-term within-group effects of a four-week multi-factorial inpatient CR programme specifically addressed to weight loss, fitness improvement and psychological health increase on 176 obese in-patients with coronary heart disease (CHD). Outcome measures were exercise capacity measured with estimated metabolic equivalents (METs), body mass index (BMI) and psychological well-being (PGWBI). Results show statistically significant improvements in all the PGWBI sub-scales and total score, except in general health (p = 0.393). No moderation effects were found for BMI class, age, diabetes and ejection fraction (EF). METs significantly increased by 30.3% (p < 0.001) and BMI decreased by 1.37 points (p < 0.001). Significant correlations were found between BMI and weight reductions with PGWBI anxiety and total score improvements. This multi-disciplinary CR programme including diet therapy, exercise training and psychological counselling provides indication for short-term within-group effectiveness on functional exercise capacity, BMI and PGWBI in a sample of obese in-patients with CHD. However, controlled studies are needed to corroborate the results we found.     

Ferrajoli’s Argument for Structural Entrenchment

This paper engages with Ferrajoli’s contribution to the philosophical debate on constitutional democracy and in particular his conception of ‘structural entrenchment’, or the basis upon which one can defend the normativity of the Constitution as ‘higher law’, which can trump or limit legislation, without infringing democratic principles. Ferrajoli’s own understanding of ‘structural entrenchment’ is compared to Rawls’s and Dworkin’s arguments in support of it. Ferrajoli’s position is neither grounded on a philosophy of history, as in Rawls, nor on a version of moral realism, as for Dworkin, but on a formal understanding of the nature of fundamental rights, and in a conception of democratic sovereignty as ‘joint ownership.’     

The Bootstrap Discovery Behaviour (BDB): a new outlook on usability evaluation

The value of λ is one of the main issues debated in international usability studies. The debate is centred on the deficiencies of the mathematical return on investment model (ROI model) of Nielsen and Landauer (1993). The ROI model is discussed in order to identify the base of another model that, respecting Nielsen and Landauer’s one, tries to consider a large number of variables for the estimation of the number of evaluators needed for an interface. Using the bootstrap model (Efron 1979), we can take into account: (a) the interface properties, as the properties at zero condition of evaluation and (b) the probability that the population discovery behaviour is represented by all the possible discovery behaviours of a sample. Our alternative model, named Bootstrap Discovery Behaviour (BDB), provides an alternative estimation of the number of experts and users needed for a usability evaluation. Two experimental groups of users and experts are involved in the evaluation of a website (). Applying the BDB model to the problems identified by the two groups, we found that 13 experts and 20 users are needed to identify 80% of usability problems, instead of 6 experts and 7 users required according to the estimation of the discovery likelihood provided by the ROI model. The consequence of the difference between the results of those models is that in following the BDB the costs of usability evaluation increase, although this is justified considering that the results obtained have the best probability of representing the entire population of experts and users.