Units

Research Unit in Cognitive Neurosciences

UNESCOG investigates the organisation and functioning of the language and cognitive system while taking its biological substrate into account.Experimental psychologists, neuropsychologists and electrophysiologists work on both normal and brain-damaged individuals in the following domains: audio-visual interactions, auditory and visual attention, speech perception and recognition, reading disturbances, cognitive consequences of schooling, literacy and ageing, organisation of the semantic system, retrieval of information from memory (in particular episodic and prospective), re-education of working memory, impairments of executive functions and of social representations due to brain lesion. Besides experimental approaches from cognitive psychology and neuropsyclology, UNESCOG's researchers employ methods of neuropsychological patient examination and of cerebral imagery (recording of evoked potentials and of hemodynamic changes).

Projetcs

Developmental dyslexia : nature of the deficits and evolution.

The goal is the determine whether the phonological and surface profiles of dyslexia stem from a common deficit (of phonological nature) or from multiple deficits. The longitudinal approach and the resort to techniques of selective training as well as the analysis of possible impairments of speech perception in dyslexic children are used to distinguish between these two hypotheses, which lead to different predictions as regards the evolution of the deficit patterns. Comparative studies with, on the one hand, patients displaying acquired deficits of reading and, on the other hand, illiterate adults allow one to examine possible analogies and determine the specific nature of developmental disturbances.

The origin of written word recognition deficits in dyslexia: Exploring the visual perception deficit hypothesis and visual training effects

The phonological deficit that is observed in most dyslexics is probably not the onlycause fortheir reading difficulties. Other reasons for their problems in forming orthographic representations may be the capacity to categorize or to memorize abstract visualinformation. In the present research project, we aim to investigate these different underlying cognitive processes. In a second step we willexplore whether these processes are sensitive to visual training.

Influence of orthographic knowledge on speech representations.

L'influence de connaissances dépendant de la litératie s'observe à différents niveaux représentationnels. Au niveau métaphonologique, notre groupe a montré que la conscience des phonèmes est présente dans les populations lettrées dans un système alphabétique, mais absente chez les illettrés. Chez les lettrés, l'influence des connaissances orthographiques dans des tâches auditives qui impliquent des composantes métaphonologiques est aussi indubitable. Plus récemment, nous avons contribué à montrer que les connaissances orthographiques affectent les processus de reconnaissance de la parole dans des tâches en ligne comme la décision lexicale, et avons étudié l'émergence de cet effet chez les jeunes apprenti-lecteurs. Notre nouveau projet combine cette recherche fondamentale avec l'application des résultats au domaine clinique. Les techniques comportementales, d'électroencéphalographie et de stimulation magnétique transcranienne seront utilisées pour examiner le profil de performance des enfants ayant des troubles d'apprentissage de la lecture (notamment la dyslexie) et les substrats neuronaux qui pourraient être à l'origine de leurs troubles. L'objectif est d'établir un diagnostic plus précis de ces troubles et éventuellement de proposer une approche de remédiation complémentaire.

Psycholinguistic units involved in speech recognition

Investigation of the prelexical units involved in the recognition of speech in French, which is compared to other languages. The paradigms used are the phonological priming and the induction of perceptual errors. One examines also the possible influence of orthographic representations on speech attentional strategies and on speech conscious analysis.

Relations between the mental representations of numbers and the mental representation of musical tones

We explore the parallels between the mental representations of music and numbers through spatial associations of response codes effects (e.g. the 'SNARC' and 'SMARC' effects). To this aim, we have adapted to musical stimuli a classical experimental paradigm from the number cognition field. This methods studies the spatial representations through the occurrence of facilitation and interference effects caused by the congruence or incongruence between a spatial response apparatus and a hypothetical mental representation. We also study the interactions between pitch height and number magnitude with the same paradigm applied to sung numbers. In addition, the effect of musical expertise on these representations is examined.

Consequences of schooling and literacy on language and cognition

The cognitive consequences of illiteracy are studied by comparing adults who were not alphabetized for socioeconomic reasons to controls who were alphabetized at adult age in alphabetic and non-alphabetic writing systems. Concerning language, both capacities of conscious, explicit analysis of speech and of perceptual processing of spoken words are examined. Concerning the other aspects of cognition, the following capacities are investigated: memory processes, problem solving, executive processes, semantic memory and its organization, and visual perception and cognition.

Relations between music and language in perception and memory for songs

These studies, conducted on non-musician participants, are aimed at testing the boundaries of separability between language and music. More specifically, we study the independence or the interactions between the phonological and semantic dimensions of the lyrics and the melodic dimension of the tune of sung stimuli. Our methods include behavioral measures (Garner's and Stroop's paradigms) as electrophy-siological ones (Event related potentials and Magnetoencéphalography).