Dissociation between components of spatial memory in rats after recovery from the effects of retrohippocampal lesions

A series of 4 experiments examined the performance of rats with retrohippocampal lesions on a spatial water-maze task. The animals were trained to find and escape onto a hidden platform after swimming in a large pool of opaque water. The platform was invisible and could not be located using olfactory cues. Successful escape performance required the rats to develop strategies of approaching the correct location with reference solely to distal extramaze cues. The lesions encompassed the entire rostro-caudal extent of the lateral and medial entorhinal cortex, and included parts of the pre- and para-subiculum, angular bundle and subiculum. Groups ECR 1 and 2 sustained only partial damage of the subiculum, while Group ECR+S sustained extensive damage. These groups were compared with sham-lesion and unoperated control groups. In Expt 1A, a profound deficit in spatial localisation was found in groups ECR 1 and ECR+S, the rats receiving all training postoperatively. In Expt 1B, these two groups showed hyperactivity in an open-field. In Expt 2, extensive preoperative training caused a transitory saving in performance of the spatial task by group ECR 2, but comparisons with the groups of Expt 1A revealed no sustained improvement, except on one measure of performance in a post-training transfer test. All rats were then given (Expt 3) training on a cueing procedure using a visible platform. The spatial deficit disappeared but, on returning to the normal hidden platform procedure, it reappeared. Nevertheless, a final transfer test, during which the platform was removed from the apparatus, revealed a dissociation between two independent measures of performance: the rats with ECR lesions failed to search for the hidden platform but repeatedly crossed its correct location accurately during traverses of the entire pool. This partial recovery of performance was not (Expt 4) associated with any ability to discriminate between two locations in the pool. The apparently selective recovery of aspects of spatial memory is discussed in relation to O'Keefe and Nadel's (1978) spatial mapping theory of hippocampal function. We propose a modification of the theory in terms of a dissociation between procedural and declarative subcomponents of spatial memory. The declarative component is a flexible access system in which information is stored in a form independent of action. It is permanently lost after the lesion. The procedural component is "unmasked" by the retrohippocampal lesion giving rise to the partial recovery of spatial localisation performance.

Goya's artwork imaging with Terahertz waves

In this paper we use a Terahertz (THz) time-domain system to image and analyze the structure of an artwork attributed to the Spanish artist Goya painted in 1771. The THz images show features that cannot be seen with optical inspection and complement data obtained with X-ray imaging that provide evidence of its authenticity, which is validated by other independent studies. For instance, a feature with a strong resemblance with one of Goya"s known signatures is seen in the THz images. In particular, this paper demonstrates the potential of THz imaging as a complementary technique along with X-ray for the verification and authentication of artwork pieces through the detection of features that remain hidden to optical inspection.

The relationship between virtual body ownership and temperature sensitivity.

In the rubber hand illusion tactile stimulation seen on a rubber hand, that is synchronous with tactile stimulation felt on the hidden real hand, can lead to an illusion of ownership over the rubber hand. This illusion has been shown to produce a temperature decrease in the hidden hand, suggesting that such illusory ownership produces disownership of the real hand. Here we apply immersive virtual reality (VR) to experimentally investigate this with respect to sensitivity to temperature change. Forty participants experienced immersion in a VR with a virtual body (VB) seen from a first person perspective. For half the participants the VB was consistent in posture and movement with their own body, and in the other half there was inconsistency. Temperature sensitivity on the palm of the hand was measured before and during the virtual experience. The results show that temperature sensitivity decreased in the consistent compared to the inconsistent condition. Moreover, the change in sensitivity was significantly correlated with the subjective illusion of virtual arm ownership but modulated by the illusion of ownership over the full virtual body. This suggests that a full body ownership illusion results in a unification of the virtual and real bodies into one overall entity - with proprioception and tactile sensations on the real body integrated with the visual presence of the virtual body. The results are interpreted in the framework of a"body matrix" recently introduced into the literature.

Ibotenate Lesions of Hippocampus and/or Subiculum: Dissociating Components of Allocentric Spatial Learning

This study examined the effects of ibotenic acid-induced lesions of the hippocampus, subiculum and hippocampus +/- subiculum upon the capacity of rats to learn and perform a series of allocentric spatial learning tasks in an open-field water maze. The lesions were made by infusing small volumes of the neurotoxin at a total of 26 (hippocampus) or 20 (subiculum) sites intended to achieve complete target cell loss but minimal extratarget damage. The regional extent and axon-sparing nature of these lesions was evaluated using both cresyl violet and Fink - Heimer stained sections. The behavioural findings indicated that both the hippocampus and subiculum lesions caused impairment to the initial postoperative acquisition of place navigation but did not prevent eventual learning to levels of performance almost as effective as those of controls. However, overtraining of the hippocampus + subiculum lesioned rats did not result in significant place learning. Qualitative observations of the paths taken to find a hidden escape platform indicated that different strategies were deployed by hippocampal and subiculum lesioned groups. Subsequent training on a delayed matching to place task revealed a deficit in all lesioned groups across a range of sample choice intervals, but the subiculum lesioned group was less impaired than the group with the hippocampal lesion. Finally, unoperated control rats given both the initial training and overtraining were later given either a hippocampal lesion or sham surgery. The hippocampal lesioned rats were impaired during a subsequent retention/relearning phase. Together, these findings suggest that total hippocampal cell loss may cause a dual deficit: a slower rate of place learning and a separate navigational impairment. The prospect of unravelling dissociable components of allocentric spatial learning is discussed.

Is my hand connected to my body? The impact of body continuity and arm alignment on the virtual hand illusion

When a rubber hand is placed on a table top in a plausible position as if part of a person"s body, and is stroked synchronously with the person"s corresponding hidden real hand, an illusion of ownership over the rubber hand can occur (Botvinick and Cohen 1998). A similar result has been found with respect to a virtual hand portrayed in a virtual environment, a virtual hand illusion (Slater et al. 2008). The conditions under which these illusions occur have been the subject of considerable study. Here we exploited the flexibility of virtual reality to examine four contributory factors: visuo-tactile synchrony while stroking the virtual and the real arms, body continuity, alignment between the real and virtual arms, and the distance between them. We carried out three experiments on a total of 32 participants where these factors were varied. The results show that the subjective illusion of ownership over the virtual arm and the time to evoke this illusion are highly dependent on synchronous visuo-tactile stimulation and on connectivity of the virtual arm with the rest of the virtual body. The alignment between the real and virtual arms and the distance between these were less important. It was found that proprioceptive drift was not a sensitive measure of the illusion, but was only related to the distance between the real and virtual arms.

Subjectively adapted high capacity lossless image data hiding based on prediction errors

This article reports on a lossless data hiding scheme for digital images where the data hiding capacity is either determined by minimum acceptable subjective quality or by the demanded capacity. In the proposed method data is hidden within the image prediction errors, where the most well-known prediction algorithms such as the median edge detector (MED), gradient adjacent prediction (GAP) and Jiang prediction are tested for this purpose. In this method, first the histogram of the prediction errors of images are computed and then based on the required capacity or desired image quality, the prediction error values of frequencies larger than this capacity are shifted. The empty space created by such a shift is used for embedding the data. Experimental results show distinct superiority of the image prediction error histogram over the conventional image histogram itself, due to much narrower spectrum of the former over the latter. We have also devised an adaptive method for hiding data, where subjective quality is traded for data hiding capacity. Here the positive and negative error values are chosen such that the sum of their frequencies on the histogram is just above the given capacity or above a certain quality.

Steganalytic Methods for the Detection of Histogram Shifting Data Hiding Schemes

Peer-reviewed

Quantitative modelling of transcription factor binding sites

Abstract One of the most important issues in molecular biology is to understand regulatory mechanisms that control gene expression. Gene expression is often regulated by proteins, called transcription factors which bind to short (5 to 20 base pairs),degenerate segments of DNA. Experimental efforts towards understanding the sequence specificity of transcription factors is laborious and expensive, but can be substantially accelerated with the use of computational predictions. This thesis describes the use of algorithms and resources for transcriptionfactor binding site analysis in addressing quantitative modelling, where probabilitic models are built to represent binding properties of a transcription factor and can be used to find new functional binding sites in genomes. Initially, an open-access database(HTPSELEX) was created, holding high quality binding sequences for two eukaryotic families of transcription factors namely CTF/NF1 and LEFT/TCF. The binding sequences were elucidated using a recently described experimental procedure called HTP-SELEX, that allows generation of large number (> 1000) of binding sites using mass sequencing technology. For each HTP-SELEX experiments we also provide accurate primary experimental information about the protein material used, details of the wet lab protocol, an archive of sequencing trace files, and assembled clone sequences of binding sequences. The database also offers reasonably large SELEX libraries obtained with conventional low-throughput protocols.The database is available at http://wwwisrec.isb-sib.ch/htpselex/ and and ftp://ftp.isrec.isb-sib.ch/pub/databases/htpselex. The Expectation-Maximisation(EM) algorithm is one the frequently used methods to estimate probabilistic models to represent the sequence specificity of transcription factors. We present computer simulations in order to estimate the precision of EM estimated models as a function of data set parameters(like length of initial sequences, number of initial sequences, percentage of nonbinding sequences). We observed a remarkable robustness of the EM algorithm with regard to length of training sequences and the degree of contamination. The HTPSELEX database and the benchmarked results of the EM algorithm formed part of the foundation for the subsequent project, where a statistical framework called hidden Markov model has been developed to represent sequence specificity of the transcription factors CTF/NF1 and LEF1/TCF using the HTP-SELEX experiment data. The hidden Markov model framework is capable of both predicting and classifying CTF/NF1 and LEF1/TCF binding sites. A covariance analysis of the binding sites revealed non-independent base preferences at different nucleotide positions, providing insight into the binding mechanism. We next tested the LEF1/TCF model by computing binding scores for a set of LEF1/TCF binding sequences for which relative affinities were determined experimentally using non-linear regression. The predicted and experimentally determined binding affinities were in good correlation.

Within- and among-population impact of genetic erosion on adult fitness-related traits in the European tree frog Hyla arborea.

Assessing in wild populations how fitness is impacted by inbreeding and genetic drift is a major goal for conservation biology. An approach to measure the detrimental effects of inbreeding on fitness is to estimate correlations between molecular variation and phenotypic performances within and among populations. Our study investigated the effect of individual multilocus heterozygosity on body size, body condition and reproductive investment of males (that is, chorus attendance) and females (that is, clutch mass and egg size) in both small fragmented and large non-fragmented populations of European tree frog (Hyla arborea). Because adult size and/or condition and reproductive investment are usually related, genetic erosion may have detrimental effects directly on reproductive investment, and also on individual body size and condition that in turn may affect reproductive investment. We confirmed that the reproductive investment was highly size-dependent for both sexes. Larger females invested more in offspring production, and larger males attended the chorus in the pond more often. Our results did not provide evidence for a decline in body size, condition and reproductive effort with decreased multilocus heterozygosity both within and among populations. We showed that the lack of heterozygosity-fitness correlations within populations probably resulted from low inbreeding levels (inferior to ca. 20% full-sib mating rate), even in the small fragmented populations. The detrimental effects of fixation load were either low in adults or hidden by environmental variation among populations. These findings will be useful to design specific management actions to improve population persistence.

Cuticular defects lead to full immunity to a major plant pathogen.

In addition to its role as a barrier, the cuticle is also a source of signals perceived by invading fungi. Cuticular breakdown products have been shown previously to be potent inducers of cutinase or developmental processes in fungal pathogens. Here the question was addressed as to whether plants themselves can perceive modifications of the cuticle. This was studied using Arabidopsis thaliana plants with altered cuticular structure. The expression of a cell wall-targeted fungal cutinase in A. thaliana was found to provide total immunity to Botrytis cinerea. The response observed in such cutinase-expressing plants is independent of signal transduction pathways involving salicylic acid, ethylene or jasmonic acid. It is accompanied by the release of a fungitoxic activity and increased expression of members of the lipid transfer protein, peroxidase and protein inhibitor gene families that provide resistance when overexpressed in wild-type plants. The same experiments were made in the bodyguard (bdg) mutant of A. thaliana. This mutant exhibits cuticular defects and remained free of symptoms after inoculation with B. cinerea. The expression of resistance was accompanied by the release of a fungitoxic activity and increased expression of the same genes as observed in cutinase-expressing plants. Structural defects of the cuticle can thus be converted into an effective multi-factorial defence, and reveal a hitherto hidden aspect of the innate immune response of plants.

Absorptiivinen kapasiteetti käytäntölähtöisessä innovaatiotoiminnassa Päijät-Hämeessä

Tutkimuksessa arvioidaan millaisia kyvykkyyksiä toimijoiltavaaditaan, jotta voidaan edistää verkostoja palvelevan innovaatiopolitiikan toteutumista ja toteuttaa käytäntölähtöistä innovaatiotoimintaa. Empiirinen osa tarkastelee Päijät-Hämeen toimijoiden asenneympäristöä ja toimimisen valmiuksia käytäntölähtöisen innovaatiotoiminnan tarpeisiin sopivaksi. Osaaminen kerääntyy yliopistopaikkakunnille ulkoisten suurtuotannon etujen mukaisesti. Ne alueet, joilla ei ole yliopistoa joutuvat luomaan muunlaista innovaatiokyvykkyyttä saavuttaakseen kilpailuetua. Siksi Päijät-Hämeen visiona on tulla johtavaksi käytäntölähtöisen innovaatiotoiminnan alueeksi hyvien toimintamallien ja tehokkaiden tiedonsiirtomekanismien avulla. Tämä vaatii alueen toimijoilta mm. korkeaa absorptiivista kapasiteettia ja heikkoja linkkejä alueen ulkopuolelle. Työn empiirinen osa koostuu 12:sta puolistrukturoidusta haastattelusta sekä kyselytutkimuksesta. Tiedonluonti ja -siirto alueelle nähtiin pääasiassa tutkimusmaailman tehtävänä, mutta varianssianalyysin perusteella tutkimusmaailma ei itse nähnyt olevansa siinä asemassa. Yhteisen kielen puuttuminen tutkimus- ja käytännön työelämän väliltä nähtiin puutteena.

Boris Vian dans ses poèmes

El artículo se propone mostrar cómo el estudio de los poemas y canciones de Boris Vian sólo cobra sentido mediante un análisis de conjunto. Tras la aparente dispersión de temas y estilos, bajo la apariencia superficial, cómica y en ocasiones incluso grotesca y banal de sus poemas y canciones, se oculta una unidad y una coherencia profundas y minuciosamente calculadas. Para expresarla Vian huye de las limitaciones de la lógica heredada de Aristóteles y opta por utilizar la técnica del collage, yuxtaponiendo una pluralidad de situaciones y acciones en las que lo real se entremezcla con lo imaginario, cuyo resultado final es la representación de una realidad única, indivisible y a la vez relativa y singular en función de cada individuo, en la que los aparentes antagonismos se revelan como elementos complementarios en el proceso de individualización y conocimiento del «yo» interior.

Les marquages corporels à l'adolescence : expression d'un mal-être profond? : se marquer pour se démarquer : du repérage des signes au choix des réponses adaptées

La problématique des marquages corporels en tant que pratiques ancestrales s'insèrent dans des formes contemporaines d'inscription corporelle. Nous nous sommes permis d'essayer de savoir s'il s'agissait toujours d'une expression d'un malaise psychologique important ? Quelles peuvent en être les conséquences ? Pourquoi marquer le corps ? La mise en oeuvre de ce travail s'est articulée en deux phases, au départ, nous avons opéré par une pré-enquête d'envergure qui a regroupé 200 adolescents (10 filles et 190 garçons). Ensuite et dans un deuxième temps nous avons interrogé dix adolescents qui se marquent la peau dont trois garçons, âgés de quinze à dix-neuf ans. Grâce à une « tri approche » : Entretien clinique, tests du Rorschach et du TAT. Les résultats auxquels nous sommes parvenus peuvent être résumés comme suit : ces pratiques expriment une souffrance qui peine à trouver une voie d'expression symbolique autre que le corps, l'angoisse et la relation d'objet du type anaclitique, l'organisation défensive renseigneraient essentiellement sur des défenses narcissiques, centrées notamment autour du clivage et le retournement sur soi, une identité fragile marquée par une image du corps et représentation de soi fragiles et un sur (dés) investissement des limites. Il s'agit d'une emprise sur le corps et sur les marques mêmes, permettant de retrouver l'objet et le recréer. À partir des principaux résultats obtenus, nous envisageons de travailler, en filigrane sur les spécificités des types de marquages corporels existant en Algérie. En effet si le présent travail s'est étayé sur une analyse prônant la globalité, un comparatif entre les types de marquages, de même, l'établissement d'un lien entre la symbolique de certaines pratiques et les soubassements psychodynamiques qui l'entourent, serait d'un apport considérable dans la compréhension du fait étudié dans ses moindres « recoins ». -- The problem of the physical markings as ancestral practices fit into contemporary forms of physical registration. We allowed to try to know if it was always about an expression of an important psychological illness? What can be the consequences? Why to mark the body? The application of this work articulated in two phases, at first, we operated by a large-scale pre- inquiry which grouped together 200 teenagers (10 girls and 190 boys). Then and in the second time we interrogated ten teenagers who mark the skin among which three boys, from fifteen to nineteen years old. Thanks to one « sorting approaches »: clinical Interview, tests of Rorschach and TAT. The results which we reached can be summarized as follows: these practices express a suffering which has difficulty in finding a way of symbolic expression other one than the body, the fear and the relation of object of the type anaclitique, the defensive organization would inform essentially about narcissistic defences, centred notably around the cleavage and the reversal on one, a fragile identity marked by an image of the body and the representation of one fragile and one on investment of the limits. It is about an influence on the body and on the marks, allowing to find the object and to recreate it. From the main obtained results, we intend to work, between the lines on the specificities of the types of physical markings existing in Algeria. Indeed if the present work supported on an analysis lauding the global nature, a comparative degree between the types of markings, also, the establishment of a link between the symbolism of certain practices and the bases psychodynamiques who surround him, would be of a considerable contribution in the understanding of the fact studied in its slightest « hidden recesses ».

Eventos Adversos Producidos Durante la Asistencia Sanitaria.

El impacto de los Eventos Adversos (EA) durante la asistencia sanitaria es un problema de salud pública de gran actualidad y muy presente a nivel mundial, provocando tres veces más muertes que los accidentes de tráfico. Afecta a todos los niveles sanitarios y perturba de forma relevante la seguridad del paciente. Los objetivos de este trabajo son: conocer la prevalencia de los EA en las unidades asistenciales españolas, comparar el impacto de estos a nivel nacional e internacional, y conocer la forma de notificación así como las estrategias de mejora de los mismos. Para ello, se llevará a cabo una revisión de la literatura bibliográfica en la que se recogerán y se analizaran artículos de carácter científico publicados en revistas indexadas en las bases de datos más consultadas. Se utilizaran artículos escritos tanto en castellano como en inglés, vinculados al área de conocimiento y de interés para esta revisión. Finalmente se han incluido 50 referencias bibliográficas. Así encontramos que los EA en los servicios de hospitalización del ámbito internacional tienen una incidencia máxima de 16.6%, y un 10.11% en España, que aumenta hasta el 25% cuando se trata de unidades especiales. El 4% producen la muerte del paciente. Más del 80% son evitables y el 95% no se notifican. Enfermería es responsable del 33% de EA producidos. Como conclusiones destaca la inexistencia de un mecanismo de prevención eficaz para menguar el impacto de los EA, pese a su gran incidencia. El miedo a represalia y la falta de consciencia de producción del EA por parte de los profesionales de la salud, hacen que se produzca una gran infra-notificación de estos, lo cual dificulta el cumplimiento de las medidas de prevención. Se debe extender la preocupación por el impacto de los EA al ámbito social, sin limitarse solamente al sanitario. Para ello, es necesario concienciar a los profesionales de la salud en primer lugar, trasladándose así a la sociedad en general, con el objetivo de disminuir el impacto en la salud pública de la llamada “Epidemia Oculta de los Errores Sanitarios”.

Transferring control demands across incidental learning tasks - Stronger sequence usage in serial reaction task after shortcut option in letter string checking

After incidentally learning about a hidden regularity, participants can either continue to solve the task as instructed or, alternatively, apply a shortcut. Past research suggests that the amount of conflict implied by adopting a shortcut seems to bias the decision for vs. against continuing instruction-coherent task processing. We explored whether this decision might transfer from one incidental learning task to the next. Theories that conceptualize strategy change in incidental learning as a learning-plus-decision phenomenon suggest that high demands to adhere to instruction-coherent task processing in Task 1 will impede shortcut usage in Task 2, whereas low control demands will foster it. We sequentially applied two established incidental learning tasks differing in stimuli, responses and hidden regularity (the alphabet verification task followed by the serial reaction task, SRT). While some participants experienced a complete redundancy in the task material of the alphabet verification task (low demands to adhere to instructions), for others the redundancy was only partial. Thus, shortcut application would have led to errors (high demands to follow instructions). The low control demand condition showed the strongest usage of the fixed and repeating sequence of responses in the SRT. The transfer results are in line with the learning-plus-decision view of strategy change in incidental learning, rather than with resource theories of self-control.