The conditions for the reproduction of the SAGUAPAC water cooperative in the city of Santa Cruz de la Sierra, Bolivia : discourse analysis

The SAGUAPAC cooperative in the city of Santa Cruz de la Sierra (Eastern Bolivia) is regularly presented as an example of cooperative successes regarding water supply and sanitation. Its efficiency, both economic and technical, is widely considered as the main reason for its attractiveness. However, without denying its importance, we show, through a discourse analysis from and about SAGUAPAC in local media, that moral and non-instrumental factors are crucial in the reproduction of the cooperative. These factors create attachment and affection toward the cooperative, through a storytelling using a four-dimensional rhetoric (mythification, identification, emotionalisation and personification). This storytelling technique, internalized in the local media discourse and materializing the so-called new spirit of capitalism, exploits the affects and instrumentalisation of local myths and legends, as well as the 'camba' ethnic identity. In that, it tends to retain SAGUAPAC members and to canvass new ones, by providing them with recognition in their quality of local community members. However, the mobilisation of social norms and power hierarchies might end up reinforcing the social exclusion of Andean non-camba immigrants, inspite of an a priori inclusive and democratic organisation.

Naturaliser la procréation médicalement assistée : sens commun et représentations en dialogue

La constante évolution des biotechnologies de la procréation médicalement assistée (PMA) introduit des nouveautés qui perturbent les représentations de la famille et du « naturel » de la procréation notamment. Ces nouveautés engendrent des préoccupations aussi bien sociales qu'individuelles sur la légitimité et les conditions du recours à la PMA. Partant d'une approche dialogique de la communication, du langage et de la cognition ainsi que de la théorie des représentations sociales, nous faisons l'hypothèse que ces perturbations sont traitées différemment selon l'activité communicative dans laquelle les individus sont engagés. Nous avons alors travaillé à partir de deux corpus de données relevant d'un type d'activité communicative différent : un corpus de presse, de l'ordre d'un discours générique, portant sur la grossesse dite « tardive » (post-ménopause) et un corpus d'entretiens de recherche, de l'ordre d'un discours singulier, avec des couples qui ont recouru à la PMA, et portant sur la cryoconservation des zygotes. Nous appuyant sur les méthodes de l'analyse thématique et de l'analyse de discours, nous centrons notre examen sur les représentations sociales de la maternité (corpus de presse) et du « naturel » (corpus d'entretiens). Nous analysons ce que ces discours permettent d'accomplir socialement, étudions le rapport qu'ils établissent à l'ordre social et symbolique et interrogeons leurs fonctions en termes de processus de « naturalisation » de la PMA. Nos résultats montrent que les nouveautés de la PMA forcent les individus à se (re)positionner dans le champ des valeurs et des normes, lis montrent aussi que, dans ce contexte, les représentations sociales existantes sont mobilisées de différentes manières en fonction des visées argumentatives poursuivies. Ceci impliquant, par ailleurs, si ce n'est une transformation, du moins un renouvellement des représentations. Ils indiquent en outre que, bien que le discours de presse et celui des entretiens ne servent pas exactement les mêmes objectifs, leurs effets de « naturalisation » de la PMA sont comparables en termes de (re)construction de la norme. D'un point de vue dialogique, ils permettent aussi d'avancer que les polémiques sociales et individuelles sont non seulement articulées mais se co-constituent. Ils témoignent aussi du fait que la référence au « naturel » renvoie, plus qu'à un problème de perturbation de la « nature », à l'idée d'une menace de l'ordre social et symbolique. De ce point de vue, les réflexions sur les pratiques de PMA méritent d'être menées par la psychologie sociale et les sciences humaines et sociales plus largement. -- The constant evolution of biotechnologies of medically assisted procreation (MAP) introduces novelties that disturb representations of the family and, notably, of what is considered « natural » in procreation. These novelties give rise to social and individual questions about the legitimacy and the conditions of the use of MAP. Drawing upon a dialogical approach to communication, language and cognition, as well as social representations theory, a hypothesis is advanced that these disturbances are handled differently, depending on the communicative activity individuals are engaged in. Two corpuses of data, representing different communicative activity types, were used: a press corpus, reflecting a generic discourse on "late" pregnancy (post-menopause), and a research interviews corpus, reflecting particular discourses developed by couples who used MAP and have cryopreserved zygotes. Using methods of thematic and discourse analysis, the study focuses on social representations of pregnancy (press corpus) and of the "natural" (interviews corpus). The analysis questions what these discourses enable to achieve socially, how they relate to the social and symbolic order, as well as their function in "naturalising" MAP. The results show that MAP novelties force individuals to (re)position themselves in the field of values and norms. They also show that, in this context, existing social representations are mobilised in different ways depending on the argumentative aims that are being pursued. This implies, if not a transformation, at minimum a renewal of representations. Additionally the results indicate that, although press and interviews discourses might not serve the same aims, their effects on "naturalising" MAP are comparable in terms of (re)constructing the norm. From a dialogical perspective, the findings also allow us to argue that social and individual polemics are not only articulated with one another but are effectively co-constituted. They also evidence the fact that the reference to the "natural" brings forth, more than a problem of disturbing "nature", a threat to the social and symbolic order. From this perspective, reflections on MAP practices deserve further attention within social psychology and social and human sciences at large.

Reversible behavioural autistic-like regression: A manifestation of a special (new?) epileptic syndrome in a 28-month-old child. A 2-year longitudinal study .

A 28-month-old boy was referred for acute onset of abnormal head movements. History revealed an insidious progressive regression in behaviour and communication over several months. Head and shoulder 'spasms' with alteration of consciousness and on one occasion ictal laughter were seen. The electroencephalograph (EEG) showed repeated bursts of brief generalized polyspikes and spike-wave during the 'spasms', followed by flattening, a special pattern which never recurred after treatment. Review of family videos showed a single 'minor' identical seizure 6 months previously. Magnetic resonance imaging was normal. Clonazepam brought immediate cessation of seizures, normalization of the EEG and a parallel spectacular improvement in communication, mood and language. Follow-up over the next 10 months showed a new regression unaccompained by recognized seizures, although numerous seizures were discovered during the videotaped neuropsychological examination, when stereotyped subtle brief paroxysmal changes in posture and behaviour could be studied in slow motion and compared with the 'prototypical' initial ones. The EEG showed predominant rare left-sided fronto-temporal discharges. Clonazepam was changed to carbamazepin with marked improvement in behaviour, language and cognition which has been sustained up to the last control at 51 months. Videotaped home observations allowed the documentation of striking qualitative and quantitative variations in social interaction and play of autistic type in relation to the epileptic activity. We conclude that this child has a special characteristic epileptic syndrome with subtle motor and vegetative symptomatology associated with an insidious catastrophic 'autistic-like' regression which could be overlooked. The methods used to document such fluctuating epileptic behavioural manifestations are discussed.

Market-Based Instruments for ecosystem services: institutional innovation or renovation?

Recent years have seen widespread experimentation with market-based instruments (MBIs) for the provision of environmental goods and ecosystem services. However, little attention has been paid to their design or to the effects of the underlying pro-market narrative on environmental policy instruments. The purpose of this article is to analyze the emergence and dissemination of the term "market-based instruments" applied to the provision of environmental services and to assess to what extent the instruments associated are genuinely innovative. The recommendation to develop markets can lead in practice to a variety of institutional forms, as we show it based on the example of payments for environmental services (PES) and biodiversity offsets, two very different mechanisms that are both presented in the literature as MBIs. Our purpose is to highlight the gap between discourse and practice in connection with MBIs.

Further characterization of the executive memory impairment following frontal lobe lesions.

In this article we describe a 41-year-old man who, following an operation to repair a ruptured anterior communicating artery aneurysm, manifested the "hallmark" features of a dysexecutive memory impairment. Of particular note was the patient's apparently normal level of recognition memory but impaired recall on tasks matched for difficulty in control subjects. However, further testing revealed that the patient's recognition memory was not normal under all circumstances. Implications of these data for the interpretation and further investigation of the dysexecutive deficit are discussed.

Mise en oeuvre de protocoles spatiaux pour analyser la modulation de processus cognitifs en fonction de la dimension émotionnelle chez le rongeur

Résumé : Emotion et cognition sont deux termes généralement employés pour désigner des processus psychiques de nature opposée. C'est ainsi que les sciences cognitives se sont longtemps efforcées d'écarter la composante «chaude »des processus «froids »qu'elles visaient, si ce n'est pour montrer l'effet dévastateur de la première sur les seconds. Pourtant, les processus cognitifs (de collecte, maintien et utilisation d'information) et émotioAnels (d'activation subjective, physiologique et comportementale face à ce qui est attractif ou aversif) sont indissociables. Par l'approche neuro-éthologique, à l'interface entre le substrat biologique et les manifestations comportementales, nous nous sommes intéressés à une fonction cognitive essentielle, la fonction mnésique, classiquement exprimée chez le rongeur par l'orientation spatiale. Au niveau du substrat, McDonald et White (1993) ont montré la dissociation de trois systèmes de mémoire, avec les rôles de l'hippocampe, du néostriatum et de l'amygdale dans l'encodage des informations respectivement épisodiques, procédurales et émotionnelles. Nous nous sommes penchés sur l'interaction entre ces systèmes en fonction de la dimension émotionnelle par l'éclairage du comportement. L'état émotionnel de l'animal dépend de plusieurs facteurs, que nous avons tenté de contrôler indirectement en comparant leurs effets sur l'acquisition, dans diverses conditions, de la tâche de Morris (qui nécessite la localisation dans un bassin de la position d'une plate-forme submergée), ainsi que sur le style d'exploration de diverses arènes, ouvertes ou fermées, plus ou moins structurées par la présence de tunnels en plexiglas transparent. Nous avons d'abord exploré le rôle d'un composant du système adrénergique dans le rapport à la difficulté et au stress, à l'aide de souris knock-out pour le récepteur à la noradrénaline a-1 B dans un protocole avec 1 ou 4 points de départ dans un bassin partitionné. Ensuite, nous nous sommes penchés, chez le rat, sur les effets de renforcement intermittent dans différentes conditions expérimentales. Dans ces conditions, nous avons également tenté d'analyser en quoi la situation du but dans un paysage donné pouvait interférer avec les effets de certaines formes de stress. Finalement, nous avons interrogé les conséquences de perturbations passées, y compris le renforcement partiel, sur l'organisation des déplacements sur sol sec. Nos résultats montrent la nécessité, pour les souris cont~ô/es dont l'orientation repose sur l'hippocampe, de pouvoir varier les trajectoires, ce qui favoriserait la constitution d'une carte cognitive. Les souris a->B KO s'avèrent plus sensibles au stress et capables de bénéficier de la condition de route qui permet des réponses simples et automatisées, sous-tendues par l'activité du striatum. Chez les rats en bassin 100% renforcé, l'orientation apparaît basée sur l'hippocampe, relayée par le striatum pour le développement d'approches systématiques et rapides, avec réorientation efficace en nouvelle position par réactivation dépendant de l'hippocampe. A 50% de renforcement, on observe un effet du type de déroulement des sessions, transitoirement atténué par la motivation Lorsque les essais s'enchaînent sans pause intrasession, les latences diminuent régulièrement, ce qui suggère une prise en charge possible par des routines S-R dépendant du striatum. L'organisation des mouvements exploratoires apparaît dépendante du niveau d'insécurité, avec différents profils intermédiaires entre la différentiation maximale et la thigmotaxie, qui peuvent être mis en relation avec différents niveaux d'efficacité de l'hippocampe. Ainsi, notre travail encourage à la prise en compte de la dimension émotionnelle comme modulatrice du traitement d'information, tant en phase d'exploration de l'environnement que d'exploitation des connaissances spatiales. Abstract : Emotion and cognition are terms widely used to refer to opposite mental processes. Hence, cognitive science research has for a long time pushed "hot" components away from "cool" targeted processes, except for assessing devastating effects of the former upon the latter. However, cognitive processes (of information collection, preservation, and utilization) and emotional processes (of subjective, physiological, and behavioral activation roue to attraction or aversion) are inseparable. At the crossing between biological substrate and behavioral expression, we studied a chief cognitive function, memory, classically shown in animals through spatial orientation. At the substrate level, McDonald et White (1993) have shown a dissociation between three memory systems, with the hippocampus, neostriatum, and amygdala, encoding respectively episodic, habit, and emotional information. Through the behavior of laboratory rodents, we targeted the interaction between those systems and the emotional axis. The emotional state of an animal depends on different factors, that we tried to check in a roundabout way by the comparison of their effects on acquisition, in a variety of conditions, of the Morris task (in which the location of a hidden platform in a pool is required), as well as on the exploration profile in different apparatus, open-field and closed mazes, more or less organized by clear Plexiglas tunnels. We first tracked the role, under more or less difficult and stressful conditions, of an adrenergic component, with knock-out mice for the a-1 B receptor in a partitioned water maze with 1 or 4 start positions. With rats, we looked for the consequences of partial reinforcement in the water maze in different experimental conditions. In those conditions, we further analyzed how the situation of the goal in the landscape could interfere with the effect of a given stress. At last, we conducted experiments on solid ground, in an open-field and in radial mazes, in order to analyze the organization of spatial behavior following an aversive life event, such as partial reinforcement training in the water maze. Our results emphasize the reliance of normal mice to be able to vary approach trajectories. One of our leading hypotheses is that such strategies are hippocampus-dependent and are best developed for of a "cognitive map like" representation. Alpha-1 B KO mice appear more sensitive to stress and able to take advantage of the route condition allowing simple and automated responses, most likely striatum based. With rats in 100% reinforced water maze, the orientation strategy is predominantly hippocampus dependent (as illustrated by the impairment induced by lesions of this structure) and becomes progressively striatum dependent for the development of systematic and fast successful approaches. Training towards a new platform position requires a hippocampus based strategy. With a 50% reinforcement rate, we found a clear impairment related to intersession disruption, an effect transitorily minimized by motivation enhancement (cold water). When trials are given without intrasession interruption, latencies consistently diminish, suggesting a possibility for striatum dependent stimulus-response routine to occur. The organization of exploratory movements is shown to depend on the level of subjective security, with different intermediary profiles between maximum differentiation and thigmotaxy, which can be considered in parallel with different efficiency levels of the hippocampus dependent strategies. Thus, our work fosters the consideration of emotion as a cognitive treatment modulator, during spatial exploration as well as spatial learning. It leads to a model in which the predominance of hippocampus based exploration is challenged by training conditions of various nature.

Genetic redox dysregulation induces behavioural deficits in the adult mouse: an animal model for schizophrenia

Background: Glutathione (GSH), a major cellular redox regulator and antioxidant, is decreased in cerebrospinal fluid and prefrontal cortex of schizophrenia patients. The gene of the key GSH-synthesizing enzyme, glutamate-cysteine ligase, modifier (GCLM) subunit, is associated with schizophrenia, suggesting that the deficit in the GSH system is of genetic origin. Using the GCLM knock-out (KO) mouse as model system with 60% decreased brain GSH levels and, thus, strong vulnerability to oxidative stress, we have shown that GSH dysregulation results in abnormal mouse brain morphology (e.g., reduced parvalbumin, PV, immuno-reactivity in frontal areas) and function. Additional oxidative stress, induced by GBR12909 (a dopamine re-uptake inhibitor), enhances morphological changes even further. Aim: In the present study we use the GCLM KO mouse model system, asking now, whether GSH dysregulation also compromises mouse behaviour and cognition. Methods: Male and female wildtype (WT) and GCLM-KO mice are treated with GBR12909 or phosphate buffered saline (PBS) from postnatal day (P) 5 to 10, and are behaviourally tested at P 60 and older. Results: In comparison to WT, KO animals of both sexes are hyperactive in the open field, display more frequent open arm entries on the elevated plus maze, longer float latencies in the Porsolt swim test, and more frequent contacts of novel and familiar objects. Contrary to other reports of animal models with reduced PV immuno-reactivity, GCLM-KO mice display normal rule learning capacity and perform normally on a spatial recognition task. GCLM-KO mice do, however, show a strong deficit in object-recognition after a 15 minutes retention delay. GBR12909 treatment exerts no additional effect. Conclusions: The results suggest that animals with impaired regulation of brain oxidative stress are impulsive and have reduced behavioural control in novel, unpredictable contexts. Moreover, GSH dysregulation seems to induce a selective attentional or stimulus-encoding deficit: despite intensive object exploration, GCLM-KO mice cannot discriminate between novel and familiar objects. In conclusion, the present data indicate that GSH dysregulation may contribute to the manifestation of behavioural and cognitive anomalies that are associated with schizophrenia.

THE ROLE OF SPINDLES FOR SLEEP: MANIPULATING OSCILLATORY ACTIVITY IN THE THALAMOCORTICAL NETWORK

Modern urban lifestyle encourages the prolongation of wakefulness, leaving less and less time for sleep. Although the exact functions of sleep remain one of the biggest mysteries in neuroscience, the society is well aware of the negative consequences of sleep loss on human physical and mental health and performance. Enhancing sleep's recuperative functions might allow shortening sleep duration while preserving the beneficial effects of sleep. During sleep, brain activity oscillates across a continuum of frequencies. Individual oscillations have been suggested to underlie distinct functions for sleep and cognition. Gaining control about individual oscillations might allow boosting their specific functions. Sleep spindles are 11 - 15 Hz oscillations characteristic for light non-rapid-eye-movement sleep (NREMS) and have been proposed to play a role in memory consolidation and sleep protection against environmental stimuli. The reticular thalamic nucleus (nRt) has been identified as the major pacemaker of spindles. Intrinsic oscillatory burst discharge in nRt neurons, arising from the interplay of low-threshold (T-type) Ca2+ channels (T channels) and small conductance type 2 (SK2) K+ channels (SK2 channels), underlies this pacemaking function. In the present work we investigated the impact of altered nRt bursting on spindle generation during sleep by studying mutant mice for SK2 channels and for CaV3.3 channels, a subtype of T channels. Using in vitro electrophysiology I showed that nRt bursting was abolished in CaV3.3 knock out (CaV3.3 KO) mice. In contrast, in SK2 channel over-expressing (SK2-OE) nRt cells, intrinsic repetitive bursting was prolonged. Compared to wildtype (WT) littermates, altered nRt burst discharge lead to weakened thalamic network oscillations in vitro in CaV3.3 KO mice, while oscillatory activity was prolonged in SK2-OE mice. Sleep electroencephalographic recordings in CaV3.3 KO and SK2-OE mice revealed that reduced or potentiated nRt bursting respectively weakened or prolonged sleep spindle activity at the NREMS - REMS transition. Furthermore, SK2-OE mice showed more consolidated NREMS and increased arousal thresholds, two correlates of good sleep quality. This thesis work suggests that CaV3.3 and SK2 channels may be targeted in order to modulate sleep spindle activity. Furthermore, it proposes a novel function for spindles in NREMS consolidation. Finally, it provides evidence that sleep quality may be improved by promoting spindle activity, thereby supporting the hypothesis that sleep quality can be enhanced by modulating oscillatory activity in the brain. Le style de vie moderne favorise la prolongation de l'éveil, laissant de moins en moins de temps pour le sommeil. Même si le rôle exact du sommeil reste un des plus grands mystères des neurosciences, la société est bien consciente des conséquences négatives que provoque un manque de sommeil, à la fois sur le plan de la santé physique et mentale ainsi qu'au niveau des performances cognitives. Augmenter les fonctions récupératrices du sommeil pourrait permettre de raccourcir la durée du sommeil tout en en conservant les effets bénéfiques. Durant le sommeil, on observe des oscillations à travers un continuum de fréquences. Il a été proposé que chaque oscillation pourrait être à l'origine de fonctions spécifiques pour le sommeil et la cognition. Pouvoir de contrôler les oscillations individuelles permettrait d'augmenter leurs fonctions respectives. Les fuseaux sont des oscillations de 11 à 15 Hz caractéristiques du sommeil à ondes lentes léger et il a été suggéré qu'elles jouent un rôle majeur pour la consolidation de la mémoire ainsi que dans la protection du sommeil contre les stimuli environnementaux. Le nucleus réticulaire du thalamus (nRt) a été identifié en tant que générateur de rythme des fuseaux. Les bouffées oscillatoires intrinsèques des neurones du nRt, provenant de l'interaction de canaux calciques à bas seuil de type T (canaux T) et de canaux potassiques à faible conductance de type 2 (canaux SK2), sont à l'origine de la fonction de générateur de rythme. Dans ce travail, j'ai étudié l'impact de la modulation de bouffées de nRT sur la génération des fuseaux pendant le sommeil en investiguant des souris génétiquement modifiées pour les canaux SK2 et les canaux CaV3.3, un sous-type de canaux T. En utilisant l'électrophysiologie in vitro j'ai démontré que les bouffées du nRT étaient abolies dans les souris knock-out du type CaV3.3 (CaV3.3 KO). D'autre part, dans les cellules nRT sur-exprimant les canaux SK2 (SK2-OE), les bouffées oscillatoires intrinsèques étaient prolongées. Par rapport aux souris wild type, les souris CaV3.3 KO ont montré un affaiblissement des oscillations thalamiques en réponse à un changement des bouffées de nRT, alors que l'activité oscillatoire était prolongée dans les souris SK2-OE. Des enregistrements EEG du sommeil dans des souris de type CaV3.3 KO et SK2-OE ont révélé qu'une réduction ou augmentation des bouffées nRT ont respectivement affaibli ou prolongé l'activité des fuseaux durant les transitions du sommeil à ondes lentes au sommeil paradoxal. De plus, les souris SK2-OE ont montré des signes de consolidation du sommeil à ondes lentes et un seuil augmenté pour le réveil, deux mesures qui corrèlent avec une bonne qualité du sommeil. Le travail de cette thèse propose que les canaux CaV3.3 et SK2 pourrait être ciblés pour moduler l'activité des fuseaux. De plus, je propose une fonction nouvelle pour les fuseaux dans la consolidation du sommeil à ondes lentes. Finalement je suggère que la qualité du sommeil peut être améliorée en promouvant l'activité des fuseaux, soutenant ainsi l'idée que la qualité du sommeil peut être améliorée en modulant l'activité oscillatoire dans le cerveau.

Neocortical maturation during adolescence: change in neuronal soma dimension.

During adolescence, cognitive abilities increase robustly. To search for possible related structural alterations of the cerebral cortex, we measured neuronal soma dimension (NSD = width times height), cortical thickness and neuronal densities in different types of neocortex in post-mortem brains of five 12-16 and five 17-24 year-olds (each 2F, 3M). Using a generalized mixed model analysis, mean normalized NSD comparing the age groups shows layer-specific change for layer 2 (p < .0001) and age-related differences between categorized type of cortex: primary/primary association cortex (BA 1, 3, 4, and 44) shows a generalized increase; higher-order regions (BA 9, 21, 39, and 45) also show increase in layers 2 and 5 but decrease in layers 3, 4, and 6 while limbic/orbital cortex (BA 23, 24, and 47) undergoes minor decrease (BA 1, 3, 4, and 44 vs. BA 9, 21, 39, and 45: p = .036 and BA 1, 3, 4, and 44 vs. BA 23, 24, and 47: p = .004). These data imply the operation of cortical layer- and type-specific processes of growth and regression adding new evidence that the human brain matures during adolescence not only functionally but also structurally.

Behavioural alteration in chronic pain: are brain glia involved?

Behavioural symptoms such as abnormal emotionality (including anxious and depressive episodes) and cognition (for instance weakened decision-making) are highly frequent in both chronic pain patients and their animal models. The theory developed in the present article posits that alterations in glial cells (astrocytes and microglia) in cortical and limbic brain regions might be the origin of such emotional and cognitive chronic pain-associated impairments. Indeed, in mood disorders (unipolar depression, anxiety disorders, autism or schizophrenia) glial changes in brain regions involved in mood control (prefrontal and cingulate cortices, amygdala and the hippocampus) have been recurrently described. Besides, glial cells have been undoubtedly identified as key actors in the sensory component of chronic pain, owing to the profound phenotypical changes they undergo throughout the sensory pathway. Hence, the possibility arises that brain astrocytes and microglia react in upper brain structures as well, mediating the related mood and cognitive dysfunctions in chronic pain. So far, only very few studies have provided results in this prospect, mainly indirectly in pain-independent researches. Nevertheless, the first scant available data seem to merge in a unified description of a brain glial reaction occurring after chronic peripheral lesion. The present article uses this scarce literature to formulate the provocative theory of a glia-driven mood and cognitive dysfunction in chronic pain, expounding upon its validity and putative therapeutical impact as well as its current limitations and expected future developments.

The impact of personality characteristics on the clinical expression in neurodegenerative disorders--a review.

Clinical experience suggests that longstanding personality characteristics as a person's most distinctive features of all are likely to play a role in how someone with dementia copes with his increasing deficiencies. Personality characteristics may have a pathoplastic effect on both behavioral and psychological symptoms (BPS) or on cognition as well as cognitive decline. Cognitive disorders accompanied by BPS are a tremendous burden for both the patient and their proxies. This review suggests that premorbid personality characteristics are co-determinants of BPS in cognitive disorders, but much effort is needed to clarify whether or not specific premorbid personality traits are associated with specific BPS as no strong links have so far emerged. This review further shows that a growing field of research is interested in the links not only between quite short-lived emotional states and cognitive processes, but also between longstanding personality traits and cognition in both healthy individuals and patients with neurodegenerative disorders. Furthermore, a few studies found that specific premorbid personality traits may be risk factors for neurodegenerative diseases. However, research findings in this area remain scarce despite a huge literature on personality and cognitive disorders in general. An important shortcoming that hampers so far the progress of our understanding in these domains is the confusion in the literature between longstanding premorbid personality traits and transient personality changes observed in neurodegenerative diseases. Few studies have based their assessments on accepted personality theories and carefully investigated premorbid personality traits in patients with cognitive disorders, although assessing personality may be complicated in these patients. Studying the impact of personality characteristics in cognitive disorders is an especially promising field of research in particular when concomitantly using neurobiological approaches, in particular structural brain imaging and genetic studies as suggested by as yet rare studies. Improved understanding of premorbid personality characteristics as determinants of both BPS or cognitive capacities or decline is likely to influence our attitudes towards the treatment of demented patients and ultimately to help in alleviating a patient's and their proxies' burden.

Comparison of radial deformability of stent posts of different aortic bioprostheses.

OBJECTIVES Little is known about the stent deformability required for optimal stented heart valve bioprosthesis design. Therefore, two bioprosthetic valves with known good long-term clinical results were tested. The strain in the radial direction of the stent posts of these valves was compared with contemporary bioprosthetic valves and a native porcine aortic root. METHODS Medtronic Intact and Carpentier-Edwards Standard (CES), and four contemporary bioprostheses, including one self-expanding prosthesis, were tested with three sonomicrometry probes per valve fixed at commissure attachment points. The mean values from 2400 data points from three measurements of the interprobe distances were used to calculate the radius of the circle circumscribed around the three probes. Changes in the radius of the aortic root at pressures 70-90 and 120-140 mmHg (pressure during diastole and systole) and that of the stent posts at 70-90 and 0-10 mmHg (transvalvular pressure gradient during diastole and systole) were compared. RESULTS An increase in radius by 7.3 ± 2.6, 8.7 ± 0.0 and 3.9 ± 0.0% for the porcine aortic root, CES and Intact valves, respectively, was observed during transition from diastolic to systolic pressure and less for contemporary bioprostheses-mean 2.5 ± 0.9%, lowest 1.2 ± 0.0. CONCLUSIONS The results indicate that the radial deformability of bioprosthetic valve stent posts can be as low as 1.2% for xenoaortic and 3.0% for xenopericardial prostheses with no compromise of valve durability. Although these results suggest that valve stent post-deformability might not be of critical importance, a concrete answer to the question of the significance of stent deformability for valve durability can be obtained only by acquiring long-term follow-up results for valve prostheses with rigid stents.