Vision, spatial cognition and intellectual disability.

Vision is the most synthetic sensory channel and it provides specific information about the relative position of distant landmarks during visual exploration. In this paper we propose that visual exploration, as assessed by the recording of eye movements, offers an original method to analyze spatial cognition and to reveal alternative adaptation strategies in people with intellectual disabilities (ID). Our general assumption is that eye movement exploration may simultaneously reveal whether, why, and how, compensatory strategies point to specific difficulties related to neurological symptoms. An understanding of these strategies will also help in the development of optimal rehabilitation procedures

The Parallel Map Theory: Ontogeny of Flexible Spatial Strategies in Young Children

The parallel map theory explains that the hippocampus encodes space with two mapping systems: The bearing map created from ―directional cues and stimulus gradients‖; The sketch map constructed from ―positional cues‖. The integrated map combines the two mapping systems. Such parallel functioning may explain paradoxes of spatial learning in intellectual disabilities. This people may be able to memorize their surroundings in a highly detailed way, thus ordering their sensory perceptions into a representation that includes the precise localization of static objects, they are not able to ―map‖ their own spatial relationship to those objects. The detection of moving objects by these same subjects contributes to a primary bearing map. The primary map is thus generated by relying on this kind of static map, but also by detecting moving objects. This process can be described as a spatial mode of processing separate objects within the structure of an absolute reference system

La dissociation triple : le statut d’une preuve dans le domaine de la neurobiologie de la mémoire

La publication en 1993 d’un article intitulé « A triple dissociation of memory systems : hippocampus, amygdala, and dorsal striatum » par R. McDonald et N. White a marqué une étape importante dans le domaine de la neurobiologie de la mémoire. Il offrait, sur la base d’un schéma expérimental élégant, la preuve d’une indépendance entre trois formes de mémoire complémentaires et leurs soubassements neuronaux. Cependant, ce travail n’a pas eu un retentissement exceptionnel et n’a pas donné lieu à..

Les émotions de la raison

En souvenir de discussions passionnantes et créatives avec Jacques Paillard Si l’on oppose raison à émotion, c’est pour affirmer la supériorité du raisonnement sur l’intuition ou, au contraire, pour reprocher à la « raison froide » son caractère inhumain. Comme si l’un ou l’autre de ces concepts devait l’emporter par sa valeur. Mais comment mettre en relation deux fonctions de nature si différente ? Et surtout comment le faire sans dépendre simultanément de chacune des deux, la raison pour co..

What Can Animal Memory Study Bring to the Assessment of Memory and Cognitive Skills for Intellectual Disability?

Three case studies are presented to investigate the possibility of evaluating memory and cognitive capacities of severe intellectual disability with attention given to the ecological environment. Two 22-year-old male patients and a 27-year-old male patient, all three with severe intellectual disability with no verbal communication skills, were evaluated with a new and original paradigm adapted to study cognition in humans from experimental paradigms. We developed a test based on animal models to complement the "home” scale of the Adolescent and Adult Psychoeducational Profile (AAPEP), an assessment instrument designed for adolescents and adults with severe developmental disabilities. Results show that the new instrument is helpful, not only to staff members who can better understand the poor performances of their patients in daily life activities but also in the elaboration of individual acquisition plans. These preliminary results demonstrate the interest in developing a larger controlled study and in publishing our procedur

Du vieillissement cérébral à la maladie d'Alzheimer : autour de la notion de plasticité

Né de la rencontre de spécialistes du vieillissement cérébral souhaitant apporter un éclairage nouveau sur ses méthodes de prise en charge et de réadaptation, cet ouvrage collectif propose une remise en question des connaissances et des pratiques relatives aux phénomènes de vieillissement, sain et pathologique. Plusieurs chapitres sont consacrés spécifiquement à la maladie d'Alzheimer, paradigme du vieillissement pathologique propice à l'approche transdisciplinaire. En offrant une analyse fouillée des difficultés cognitives liées à l'âge, des mécanismes moléculaires au comportement, les dix-huit auteurs s'adressent tout autant au praticien qui recherche des fondements théoriques qu'à l'étudiant qui désire comprendre comment les connaissances issues de la recherche fondamentale s'articulent avec la pratique [Ed.]]]> Alzheimer Disease ; Aging fre oai:serval.unil.ch:BIB_5B425FAC4497 2022-10-01T01:20:37Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_5B425FAC4497 Techniques d'évaluation de la force des muscles respiratoires. [Techniques for assessing respiratory muscle strength.] info:doi:10.1016/S1779-0123(09)70031-2 info:eu-repo/semantics/altIdentifier/doi/10.1016/S1779-0123(09)70031-2 Fitting, J.W. info:eu-repo/semantics/review article 2009 Kinésithérapie, vol. 9, no. 94, pp. 23-27 info:eu-repo/semantics/altIdentifier/pissn/1779-0123 <![CDATA[La faiblesse des muscles respiratoires peut entraîner une dyspnée, un encombrement bronchique et une insuffisance respiratoire potentiellement fatale. L'évaluation de la force musculaire respiratoire s'impose donc dans les affections neuro-musculaires, mais également dans les situations de dyspnée inexpliquée par une première évaluation cardiaque et pulmonaire. À la spirométrie, une faiblesse musculaire est suspectée sur la base de la boucle débit-volume montrant un débit de pointe émoussé et une fin prématurée de l'expiration. Une diminution importante de la capacité vitale en position couchée suggère une paralysie diaphragmatique. La force inspiratoire est mesurée par la pression inspiratoire maximale (PImax) contre une quasi-occlusion des voies aériennes. Ce test relativement difficile est d'interprétation délicate en cas de collaboration insuffisante. La mesure de la pression nasale sniff (SNIP) est une alternative utile, car elle élimine le problème des fuites autour de l'embout buccal et la réalisation du reniflement est facile. De même, la pression trans-diaphragmatique sniff mesure la force du diaphragme au moyen de sondes oesophagienne et gastrique. En cas de collaboration insuffisante, on peut recourir à la stimulation magnétique des nerfs phréniques qui induit une contraction non-volontaire du diaphragme. La force expiratoire est mesurée par la pression expiratoire maximale (PEmax) contre une quasi-occlusion. La force disponible pour tousser est mesurée par la pression gastrique à la toux, ou plus simplement par le débit de pointe à la toux. Chez les patients à risque, la mesure de la force des muscles respiratoires permet d'instaurer à temps une assistance ventilatoire ou à la toux

Characterization of the HeCo Mutant Mouse: A New Model of Subcortical Band Heterotopia Associated with Seizures and Behavioral Deficits

In human, neuronal migration disorders are commonly associated with developmental delay, mental retardation, and epilepsy. We describe here a new mouse mutant that develops a heterotopic cortex (HeCo) lying in the dorsolateral hemispheric region, between the homotopic cortex (HoCo) and subcortical white matter. Cross-breeding demonstrated an autosomal recessive transmission. Birthdating studies and immunochemistry for layer-specific markers revealed that HeCo formation was due to a transit problem in the intermediate zone affecting both radially and tangentially migrating neurons. The scaffold of radial glial fibers, as well as the expression of doublecortin is not altered in the mutant. Neurons within the HeCo are generated at a late embryonic age (E18) and the superficial layers of the HoCo have a correspondingly lower cell density and layer thickness. Parvalbumin immunohistochemistry showed the presence of gamma-aminobutyric acidergic cells in the HeCo and the mutant mice have a lowered threshold for the induction of epileptic seizures. The mutant showed a developmental delay but, in contrast, memory function was relatively spared. Therefore, this unique mouse model resembles subcortical band heterotopia observed in human. This model represents a new and rare tool to better understand cortical development and to investigate future therapeutic strategies for refractory epileps

Visuospatial encoding deficits and compensatory strategies in schizophrenia revealed by eye movement analysis during a working memory task

Objective: To investigate scanpath abnormalities during the encoding of static stimuli in schizophrenia and their interaction with visuospatial working memory (VSWM) dysfunction. Methods: Outpatients with schizophrenia and control subjects were asked to encode a static pattern for subsequent recognition after a short delay. We measured the number of correct and incorrect choices. We also assessed the number and the distribution of fixations, the scanning time in specific regions of interest (ROIs) and the head movements during the encoding of the stimuli. The distributions of fixations and scanning time in definite ROIs during the discrimination of the correct pattern from the foils were also measured. Results: Patients recognised fewer correct patterns than controls. Correct trials in patients were characterised by a specific exploration of the central part of the stimulus during its presentation, whereas this feature was absent in incorrect trials. However, the scanning time and the numbers of fixations and head movements during encoding were similar in both groups and unrelated to recognition accuracy. In both groups, correct trials were associated with a selective exploration of the correct pattern amongst the six possibilities during recognition. Furthermore, patients gave more attention to incorrect patterns with a leftmost element identical to that of the correct response and also those approximating its global structure. Conclusion: Patients showed a VSWM deficit independent of oculomotor dysfunctions and head movements during encoding. Patients' correct trials were related to specific scanning during encoding and discrimination phases. Analysis of these patterns suggests that patients try to compensate for reduced VSWM ability by using specific encoding strategie

La mémoire chez l'animal : évolution récente de quelques concepts utilisés en psychophysiologie

Summary : Recent trends in animal memory : Functional dissociations and the hippocampus. This paper discusses brain-behavior relationships in animal memory and some methods which allow the use of experimental data for a more general understanding of brain processes underlying memory. In a first part, a brief overview reveals some critical developments which have occurred in the last 20 years. Included among these are the analysis of cognitive processes in animal behavior, the increasing amount of anatomical and physiological data showing that the limbic system is functionally associated with the neocortex, and the proposition by O'Keefe and Nadel (1978) of a neural substrate for cognitive maps in rats. In addition, two methodological trends are considered, the development of specifically spatial tasks for rats and monkeys, and, more generally, the tendency to use equivalent tasks in animais and humans. In a second part, we discuss some current concepts used in experimental approaches to dissociate memory functions, and the conditions under which these concepts can be applied to dissociations observed in animals and humans. First, we consider the value of spatial memory as a specific hippocampal function. Subsequently, we analyze whether memory components such as working or declarative memory are specific enough to account for dissociations induced by hippocampal lesions. Key-words : spatial memory, working memory, declarative memory, hippocampus.Dans cet article, nous cherchons à faire le point sur l'évolution récente de quelques concepts et méthodes d'analyse utilisés pour étudier la mémoire chez l'animal, et évaluer le rôle de structures nerveuses — essentiellement l'hippocampe — dans différentes formes de mémoire. Tout d'abord, nous relevons dans les vingt dernières années les développements qui ont contribué à l'adéquation du modèle animal pour approcher les phénomènes mnésiques dans une perspective évolutionniste permettant l'extrapolation à l'homme. Puis nous discutons la valeur de quelques catégories de mémoire (mémoires spatiale, déclarative, de travail) utilisées pour rendre compte de dissociations fonctionnelles induites expérimentalement ou observées en clinique. Mots clés : mémoire spatiale, mémoire de travail, mémoire déclarative, hippocampe.Schenk Françoise. La mémoire chez l'animal : évolution récente de quelques concepts utilisés en psychophysiologie. In: L'année psychologique. 1992 vol. 92, n°2. pp. 233-261