The action of prism adaptation on intact visuospatial cognition : when time matters to space Selene Schintu To cite this version: Selene Schintu. The action of prism adaptation on intact visuospatial cognition : when time matters to space. Neurons and Cognition [q-bio.NC]. Université Claude Bernard - Lyon I, 2014. English. NNT : 2014LYO10320. tel-01132932 HAL Id: tel-01132932 https://tel.archives-ouvertes.fr/tel-01132932 Submitted on 18 Mar 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. N° d’ordre 320 - 2014 Année 2014 THESE DE L‘UNIVERSITE DE LYON Délivrée par L’UNIVERSITE CLAUDE BERNARD LYON 1 ECOLE DOCTORALE Neuroscience et Cognition DIPLOME DE DOCTORAT (arrêté du 7 août 2006) Soutenue publiquement le 18 Décembre 2014 par : SCHINTU Selene The action of prism adaptation on intact visuospatial cognition - when time matters to space Sous la direction du Dr. Alessando Farné Co-directeur Dr. Karen T. Reilly and Dr. Laure Pisella COMPOSITION DU JURY Paolo Bartolomeo, M.D., Ph.D. Rapporteur Robert McIntosh, Ph.D. Rapporteur Alessandro Farné, Ph.D. Examinateur Yves Rossetti, M.D., Ph.D. Examinateur Karen T. Reilly, Ph.D. Membre invité Laure Pisella, Ph.D. Membre invité Centre de Recherche en Neurosciences de Lyon, INSERM 1028, CNRS UMR 5292, Univeristé de Lyon I, Equipe ImpAct (Integrative, Multisensory, Perception Action and Cognition Team). UNIVERSITE CLAUDE BERNARD - LYON 1 Président de l’Université M. François-Noël GILLY Vice-président du Conseil d’Administration M. le Professeur Hamda BEN HADID Vice-président du Conseil des Etudes et de la Vie Universitaire M. le Professeur Philippe LALLE Vice-président du Conseil Scientifique M. le Professeur Germain GILLET Directeur Général des Services M. Alain HELLEU COMPOSANTES SANTE Faculté de Médecine Lyon Est – Claude Bernard Directeur : M. le Professeur J. ETIENNE Faculté de Médecine et de Maïeutique Lyon Sud – Charles Mérieux Directeur : Mme la Professeure C. BURILLON Faculté d’Odontologie Directeur : M. le Professeur D. BOURGEOIS Institut des Sciences Pharmaceutiques et Biologiques Directeur : Mme la Professeure C. VINCIGUERRA Institut des Sciences et Techniques de la Réadaptation Directeur : M. le Professeur Y. MATILLON Département de formation et Centre de Recherche en Biologie Humaine Directeur : Mme. la Professeure A-M. SCHOTT COMPOSANTES ET DEPARTEMENTS DE SCIENCES ET TECHNOLOGIE Faculté des Sciences et Technologies Directeur : M. F. DE MARCHI Département Biologie Directeur : M. le Professeur F. FLEURY Département Chimie Biochimie Directeur : Mme Caroline FELIX Département GEP Directeur : M. Hassan HAMMOURI Département Informatique Directeur : M. le Professeur S. AKKOUCHE Département Mathématiques Directeur : M. le Professeur Georges TOMANOV Département Mécanique Directeur : M. le Professeur H. BEN HADID Département Physique Directeur : M. Jean-Claude PLENET UFR Sciences et Techniques des Activités Physiques et Sportives Directeur : M. Y.VANPOULLE Observatoire des Sciences de l’Univers de Lyon Directeur : M. B. GUIDERDONI Polytech Lyon Directeur : M. P. FOURNIER Ecole Supérieure de Chimie Physique Electronique Directeur : M. G. PIGNAULT Institut Universitaire de Technologie de Lyon 1 Directeur : M. le Professeur C. VITON Ecole Supérieure du Professorat et de l’Education Directeur : M. le Professeur A. MOUGNIOTTE Institut de Science Financière et d'Assurances Directeur : M. N. LEBOISNE The function of ignoring, of inattention, is as vital a factor in mental progress as the function of attention itself. William James, In The Principles of Psychology (1918). To Fabiola ACKNOWLEDGMENTS Thanks Alessandro, for always listening to understand. Your passion, commitment and integrity have taught me more than anything else. It has been an honor being your student. Thank Karen, for having taught me how to put a structure around my thoughts, to be consistent and, to try at least, to be rigorous. It has been an intense and unique moment of my Life, thanks for having been with me. Thanks Laure, for having been the calm and peaceful presence that completes the team, for discussing until the last minutes, and caring so much until the very end. Thanks to the whole lab and for all the smiling faces and kind words you had for me. Thanks, Fadila, you gave me the click (and I do not mean the VOSP)! Stephane, you always made sure that at least one hemisphere was “awake”. Martine, the last sweet word of most of my evenings in the lab. Oh Romeo, Romeo .... how could I have made it without you? A special thanks goes to Delphine, Dollyane and Clement; we shared more than a job! Guys, these three years with you have been so much fun. You will be always in my heart. A special thanks goes to my mum, my dad, my grandma; who always sustained me even if this meant (and will mean) to be far from them. And finally thanks to you Olga. You are right; we always have to choose to do what we do not know yet. I just did it, and I did enjoy the journey. PREFACE We are, functionally and structurally, asymmetric bodies. One foot is often smaller than the other one, and one leg longer than its counterpart. Our facial expressions are also asymmetric, with the left side appearing more expressive than the right. From the bottom to the top, from the feet to the brain, we are a dichotomy working together to create the unique person we are. Even with our brains, similar to many other mammals, our two cerebral hemispheres differ in their anatomy and functions. This hemispheric specialization has been thought to be so strong as to determine even our personality and skills, and has led to the popularly-held belief that there are “right- brain” and “left-brain” people. While this belief belongs in the realm of pseudo- science, what has been demonstrated is that some cognitive abilities, such as language and spatial perception, do indeed depend predominantly on the left and right hemispheres, but that the two hemispheres work in synergy to ensure, at first sight, balanced visuospatial cognition and full language abilities. In fact, the perfect symmetry we subjectively experience through vision of the space around us is, to some extent, an illusion. When we are asked to judge spatial quantities across the vertical meridian of our visual field an asymmetry can be readily detected. This asymmetry in visuospatial cognition can be quantified behaviorally with a simple task such as the line bisection task. If we are asked to mark or judge the center of a horizontal line most of us will bisect it slightly to the left of its true center. This bias, typical of neurologically healthy subjects, is predominantly leftward in young subjects and moves rightward with age, and can reach pathological levels after right brain damage when the center of a line is sometimes perceived very far to the right of the true center. This pathological rightward bias is one of the symptoms very often exhibited by people affected by unilateral spatial neglect syndrome (USN), which is a pervasive and multi-componential syndrome that can affect diverse aspects of daily life. From bisecting a line rightward or copying only the right side of a drawing, to shaving only the right cheek or omitting to eat food on the left side of the dish, USN is a condition that very often limits the functional outcome of patients who are usually recovering from the stroke that caused this severely handicapping but fascinating pathology. Performance on line bisection tasks has also been shown to be relatively manipulable in both pathological and intact brains. Among the different ways of modulating it, prism adaptation (PA) can both ameliorate USN symptoms (induce a leftward shift in line bisection judgments – towards the true midline), and induce neglect-like behavior in healthy subjects (induce a rightward shift in line bisection judgments). Despite years of research, however, how this relatively simple visuomotor adaptation can modulate and remediate spatial cognition is still unknown. Uncovering the mechanism responsible for the PA-induced shift in line bisection judgments in healthy individuals would not only answer this question but would also shed light on the pathology of USN per se and contribute to our general understanding of visuospatial cognition. ABSTRACT We are functionally and structurally asymmetric. The perfect symmetry we subjectively experience through vision of the space around us is, to some extent, an illusion. Visuospatial cognition, as indexed by performance on line bisection tasks, is generally biased leftward in healthy individuals and pathologically rightward after right brain damage causing unilateral spatial neglect (USN). These biases can be modulated and prism adaptation (PA) is capable of both alleviating USN symptoms and inducing a rightward shift (the so-called “neglect-like behavior”) in healthy individuals. How this type of sensorimotor adaptation modulates spatial cognition is still debated. The goal of this thesis was to use both behavioral and physiological approaches to investigate the underlying mechanisms of PA’s effects on visuospatial cognition in healthy individuals. In a first behavioral study we found the presence of a temporal dynamic in PA after-effects. Based on this first finding we tested, over a longer period of time the PA after-effects following both right and leftward PA and unveiled, with the second study, different temporal dynamics depending on PA direction. In a third study we used transcranial magnetic stimulation to investigate the physiology underlying the effective visuospatial modulation induced by PA. The results of this thesis call for a refinement of the current models of PA action on visuospatial cognition.