Factor Uniqueness of the Structural Parafac Model

Psychometrika - Factor analysis is a well-known method for describing the covariance structure among a set of manifest variables through a limited number of unobserved factors. When the observed...     

Depressive symptoms and one year mortality among elderly patients discharged from a rehabilitation ward after orthopaedic surgery of the lower limbs

The objective of the present prospective observational study is to evaluate the effect of depressive symptoms on 1-year mortality in a population of elderly patients discharged from a rehabilitation unit after orthopaedic surgery of the lower limbs. A total of 222 elderly inpatients were included, and stratified according to 12-months survival. 14 (6.3%) of the patients who were eligible for this study died during the 12-months period after discharge. As expected, patients who died were significantly older, lower cognitive performance, more depressive symptoms, poorer nutritional status and higher comorbidity in comparison to those who survived. Furthermore, they were generally more functionally dependent on admission to the Department, had worse functional recovery and were more disable at discharge, although a longer length of stay comparing to survived patients. In the adjusted logistic regression model, after adjustment for possible confounders and covariates, the presence of severe depressive symptoms significantly predicted a four-fold risk of death at 12 months. The only other factor associated poor 12-months survival was comorbidity, that predicted a 6-fold risk of death. In conclusions this study suggests that severe depressive symptoms on admission predicts 1-year mortality in elderly patients discharged from a post-acute care unit after orthopaedic rehabilitation.     

Increased levels of conditioned fear and avoidance behavior coincide with changes in phosphorylation of the protein kinase B (AKT) within the amygdala in a mouse model of extremes in trait anxiety

Patients diagnosed for anxiety disorders often display faster acquisition and slower extinction of learned fear. To gain further insights into the mechanisms underlying these phenomenona, we studied conditioned fear in mice originating form a bi-directional selective breeding approach, which is based on elevated plus-maze behavior and results in CD1-derived high (HAB), normal (NAB), and low (LAB) anxiety-related behavior mice. HAB mice displayed pronounced cued-conditioned fear compared to NAB/CD1 and LAB mice that coincided with increased phosphorylation of the protein kinase B (AKT) in the basolateral amygdala 45 min after conditioning. No similar changes were observed after non-associative immediate shock presentations. Fear extinction of recent but not older fear memories was preserved. However, HAB mice were more prone to relapse of conditioned fear with the passage of time. HAB mice also displayed higher levels of contextual fear compared to NAB and LAB mice and exaggerated avoidance following step-down avoidance training. Interestingly, HAB mice showed lower and LAB mice higher levels of acoustic startle responses compared to NAB controls. The increase in arousal observed in LAB mice coincided with the general absence of conditioned freezing. Taken together, our results suggest that the genetic predisposition to high anxiety-related behavior may increase the risk of forming traumatic memories, phobic-like fear and avoidance behavior following aversive encounters, with a clear bias towards passive coping styles. In contrast, genetic predisposition to low anxiety-related and high risk-taking behavior seems to be associated with an increase in active coping styles. Our data imply changes in AKT phosphorylation as a therapeutic target for the prevention of exaggerated fear memories.     

Parietal versus temporal lobe components in spatial cognition: Setting the mid‐point of a horizontal line

Recent anatomo‐clinical correlation studies have extended to the superior temporal gyrus, the right hemisphere lesion sites associated with the left unilateral spatial neglect, in addition to the traditional posterior‐inferior‐parietal localization of the responsible lesion (supramarginal gyrus, at the temporo‐parietal junction). The study aimed at teasing apart, by means of repetitive transcranial magnetic stimulation (rTMS), the contribution of the inferior parietal lobule (angular gyrus versus supramarginal gyrus) and of the superior temporal gyrus of the right hemisphere, in making judgments about the mid‐point of a horizontal line, a widely used task for detecting and investigating spatial neglect. rTMS trains at 25 Hz frequency were delivered over the inferior parietal lobule (angular gyrus and supramarginal gyrus), the superior temporal gyrus and the anterior parietal lobe of the right hemisphere, in 10 neurologically unimpaired participants, performing a line bisection judgment task. rTMS of the inferior parietal lobule at the level of the supramarginal gyrus brought about a rightward error in the bisection judgment, ipsilateral to the side of the rTMS, with stimulation over the other sites being ineffective. The neural correlates of computing the mid‐point of a horizontal segment include the right supramarginal gyrus in the inferior parietal lobule and do not extend to the angular gyrus and the superior temporal gyrus. These rTMS data in unimpaired subjects constrain the evidence from lesion studies in brain‐damaged patients, emphasizing the major role of a subset of relevant regions.     

How different spatial representations interact in virtual environments: the role of mental frame syncing

This experiment is aimed at understanding how egocentric experiences, allocentric viewpoint-dependent representations, and allocentric viewpoint-independent representations interact when encoding and retrieving a spatial environment. Although several cognitive theories have highlighted the interaction between reference frames, it is less clear about the role of a real-time presentation of allocentric viewpoint-dependent representation on the spatial organization of information. Sixty participants were asked to navigate in two virtual cities to memorize the position of one hidden object. Half of the participants had the possibility to visualize the virtual city with an interactive aerial view. Then, they were required to find the position of the object in three different experimental conditions (“retrieval with an interactive aerial view” vs. “retrieval on a map” vs. “retrieval without an interactive aerial view”). Results revealed that participants were significantly more precise in retrieving the position of the object when immersed in an egocentric experience with the interactive aerial view. The retrieval of spatial information is facilitated by the presence of the interactive aerial view of the city, since it provides a real-time allocentric viewpoint-dependent representation. More participants with high preference for using cardinal points tend to be more accurate when they were asked to retrieve the position of the object on the map. As suggested by the mental frame syncing hypothesis, the presence of an allocentric viewpoint-dependent representation during the retrieval seems to ease the imposition on a specific viewpoint on the stored abstract allocentric viewpoint-independent representation. Our findings represent another significant step toward the comprehension of the organization of spatial representations of our environment.     

Multiple-criteria decision aid: Some epistemological considerations

This paper attempts to analyse in a critical way some essential aspects of the multiple-criteria decision aid (MCDA) methodology using modern epistemological instruments. Particular attention is paid to the problem of information precision and uncertainty and to the distinction considered essential between the concepts of choice and decision. Since it is maintained that the respect of subjectivity in decision aid is of fundamental importance, an analysis follows of the main approaches by which MCDA methods attempt to take the subjective component of the decision maker into account, indicating some characteristics which may be desirable in an MCDA model for this purpose.