Séminaires des laboratoires

29/09/2017 - LPC - Séminaire George Michael

 

11 heures - LPC, Salle des Voûtes, Campus St Charles - 13003 Marseille

George Michael
Université Lumière, Lyon 2

15/09/2017 - LPC - Séminaire Zoltan Dienes

 

11 heures - LPC, Salle des Voûtes, Campus St Charles - 13003 Marseille

Zoltan Dienes
Professor of Psychology
School of Psychology
University of Sussex

07/07/2017 - LPC - Séminaire Susana Chung

11 heures - LPC, Salle des Voûtes - campus St Charles - 13003 Marseille

Susana Chung
Berkeley University of California

03/07/2017 - LNC - Nicolas Mallet (Institut des maladies neurodégénératives, Bordeaux)

 

Optogenetic dissection of circuit mechanism underlying beta-oscillation expression in Parkinsonism

The basal-ganglia (BG) form a complex loop with the cortex and the thalamus that is involved in action selection and movement control. Synchronized oscillatory activities in BG neuronal circuits have been proposed to play a key role in coordinating information flow within this neuronal network. If synchronized oscillatory activities are important for normal motor function, their dysregulation in space and time could be truly pathological. Indeed, in Parkinson’s disease (PD), many studies have reported an abnormal increase in the expression level of neuronal oscillations contained in the beta (β) frequency range (15-30 Hz). These abnormal β oscillations have been proposed to be responsible for two motor symptoms of PD : akinesia and bradykinesia. However, which neuronal circuits generate these abnormal β oscillations that propagate through the entire BG loop is not known. The subthalamic nucleus (STN) is a key nucleus in BG that receives converging inputs from the motor cortex (mCx) and the external globus pallidus (GP). It has been proposed that the reciprocally connected STN-GP microcircuit could act as a pacemaker that generates pathological oscillatory activity in BG but it is difficult to rule out the influence of mCx in this generation mechanism. Here, we used a rat model of PD combined with in vivo electrophysiological recordings and optogenetic manipulations to directly dissect how selective control of mCx, STN and GP causally influence BG network dynamic at beta frequencies. Our data both challenge the implication of mCx and STN in the generation mechanisms of abnormal β-oscillations but highlight the central role of GP that is necessary and sufficient for the maintenance of synchronized β activities in dopamine-depleted state.

 

12/06/217 - LNC - Bruno Lebrun (Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif))

enir (upcoming seminars)

Bruno Lebrun (Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif))

Les cellules gliales : des acteurs de poids dans le contrôle de l’homéostasie énergétique

Alors que depuis deux décennies, les efforts se concentrent sur l’identification des réseaux neuronaux de l’hypothalamus et du complexe vagal dorsal (CVD) impliqués dans la régulation homéostatique de la balance énergétique, nous avons choisi de tester l’hypothèse de l’implication des cellules gliales dans ces régulations. Dans ce contexte, nous nous intéressons particulièrement aux endozépines. Les endozépines sont connues pour induire un effet anorexigène, indépendamment de leur action sur les récepteurs des benzodiazépines. Nous avons montré que les endozépines sont exprimées par plusieurs populations gliales dans l’hypothalamus et le CVD, à des niveaux dépendant du statut nutritionnel. De façon intéressante, nous avons observé, chez des souris rendues résistantes à la leptine par une nourriture enrichie en graisses, qu’un traitement central par les endozépines permet de normaliser la sensibilité à la leptine et de supprimer l’hyperphagie et le surpoids de ces souris. Cette action impliquerait une augmentation du transport de la leptine vers le parenchyme cérébral et ceci via une sous population gliale particulière les tanycytes. Parallèlement, nous recherchons par quel(s) mécanisme(s) les cellules gliales de l’hypothalamus et du CVD peuvent libérer des substances susceptibles de modifier la balance énergétique. Les connexines Cx43 exprimées par les cellules gliales et formant non seulement des jonctions communicantes mais également des hémi-canaux connus pour permettre l’émission de gliotransmetteurs sont des candidates potentielles. Le niveau d’expression de Cx43 dans l’hypothalamus et le CVD est fonction du statut nutritionnel. L’administration centrale d’un agent pharmacologique empêchant sélectivement l’ouverture des hémi-canaux de Cx43 entraîne un fort effet anorexigène et recrute les neurocircuiteries anorexigènes de l’hypothalamus et du CVD. Ces résultats suggèrent que les cellules gliales peuvent également émettrent de façon tonique des gliotransmetteurs orexigènes via les hémi-canaux Cx43. A la lumière de ces résultats, nous pensons que le compartiment glial doit être pris en compte dans l’étude du contrôle de l’homéostasie énergétique, et nous développons actuellement plusieurs modèles génétiques pour conforter nos observations. A terme, nous pensons qu’une meilleure compréhension du compartiment glial de l’hypothalamus et de CVD est susceptible de fournir des pistes thérapeutiques originales pour lutter contre les dérèglements de la balance énergétique.

 

09/06/2017 - LNC - Neil Schwartz (Univ California, San Francisco)

Neil Schwartz (Univ California, San Francisco)

Cortico-striatal regulation of conflicting behavioral drives​

I am interested in experience- and pathological-associated regulation of motivated behavior. In my talk, I’ll describe 2 projects in which we investigated how experience-dependent and chronic pain-associated changes in cortico-striatal circuits regulate approach-avoidance choice and motivation to work for a reward.

 

02/06/2017 - LPC - Séminaire Aurélie Calabrèse

 

11 heures - LPC, Salle des Voûtes, Campus St Charles - 13003 Marseille

Aurélie Calabrèse
Laboratoire de Psychologie Cognitive
CNRS & AMU

Understanding the reading deficits of individuals with central vision loss to help restore their reading abilities.

Age-related macular degeneration (AMD) accounts for 8.7% of all blindness worldwide and is the most common cause of blindness in developed countries. Older adults suffering from AMD often lose the ability to use central vision after developing a central scotoma. Despite advances in the treatment of wet AMD, central vision cannot be restored and difficulty with reading is often the primary complaint of AMD patients, who have to use their peripheral vision for reading. The number of Europeans with AMD, and who struggle with reading, is expected to reach 60 million by 2030. When eye disorders limit people’s access to printed text, the issue is vision disability, not literacy, but the individual consequences may be just as severe.

The focus of this talk will be to present some of the latest progress made to understand (and therefore overcome) the underlying factors of the reading deficits following central vision loss (CVL). Questions that will be covered include: what sensory, cognitive and oculo-motor factors can explain slow reading speed with CVL? Can reading performance be improved through training and what are the cortical sites involved in this improvement? How to optimize reading aids and reading diagnostic tools?

24/04/2017 - LNC - Christian Ruff (Laboratory for Social and Neural Systems Research, Université de Zurich)

 Christian Ruff (Laboratory for Social and Neural Systems Research, Université de Zurich)  24/04/2017 à 13:30

03/04/2017 - LNC - Randi Starrfelt (University of Copenhague)

 Randi Starrfelt (University of Copenhague)  03/04/2017 à 13:30

27/03/2017 - LNC - Giulio Casali (UCL, London)

 Giulio Casali (UCL, London)  27/03/2017 à 13:30

10/03/2017 - LPC - Steve Fleming

Vendredi 10 mars 2017 - LPC
Steve Fleming
Wellcome Trust Centre for Neuroimaging
University College London

30/01/2017 - LNC - Laure Verret (CNRS/Université Paul Sabatier, Toulouse)

Laure Verret (CNRS/Université Paul Sabatier, Toulouse)

Social Memory Impairments and Area CA2 Modifications in a Mouse Model of Alzheimer’s Disease

Among the cognitive impairments observed in Alzheimer’s disease (AD) patients, one of the most excruciating is their inability to recognize or remember other people. Distressingly, social memory and recognition have been barely investigated in AD mouse models, and little is known about the neural substrates of social memory impairments in AD. Very recently, it has been demonstrated that inactivation of area CA2 pyramidal neurons induces specific social memory impairments (Hitti & Siegelbaum 2014), and this hippocampal structure is now considered as a critical hub for sociocognitive memory processing (Chevaleyre & Piskorowski 2016). Thus, we hypothesized that social memory impairments in AD mouse models could be mediated by area CA2 dysfunction. We observed anatomical modifications in the area CA2 of AD mice, which are inducing decreased inhibitory control of CA2 pyramidal cells, and are associated with social recognition and social memory impairments. We are now exploring whether there is a causal link between these anatomical alterations in area CA2 and social memory deficits in the context of AD.
 

30/01/2017 à 13:30

02/12/2016 - LPC - General and Biological Psychology, University of Wuppertal Man and Machine during Natural Language Processing : A Neurocognitive Approach

     Vendredi 2 décembre 2016 - LPC - BLRI
    16 heures, salle des Voûtes
    Chris Biemann and Markus J. Hofmann
    Language Technology, Universität Hamburg

General and Biological Psychology, University of Wuppertal
Man and Machine during Natural Language Processing : A Neurocognitive Approach

While state-of-the-art NLP models lack a theory that systematically accounts for human performance at all levels of linguistic analysis, Neurocognitive Simulation Models of orthographic and phonological memory so far lacked a level of implemented semantic representations. To overcome these limitations, the authors of this talk decided to initiate a long-standing cooperation.
In part 1 of this talk, we introduce unsupervised methods from language technology that capture semantic information. We present a range of methods that extract semantic representation from corpora, as opposed to using manually created norms. We show how we applied language models based on n-grams, topic modelling, and the word2vec neural model across three different corpora to account for behavioral, brain-electric and eye movement data. We used a benchmark that has become standard for Neurocognitive Simulation Models in psychology : Thus we reproducibly accounted for half of the item-level variance in the cloze-completion-based word predictability from sentence context, and the resulting N400-, and single fixation duration data of the Potsdam sentence corpus.
In part 2 we discuss how relatively straightforward NLP methods can be used to define semantic processes in a neurocognitive simulation model. To extend an interactive activation model with a semantic layer, we used the log likelihood that two words occur more often together in the sentences of a large corpus than predictable by single-word frequency. The resulting Associative Read-Out Model (AROM) is an extension of the Multiple Read-Out Model. Here, we use it to account for association ratings and semantically induced false memories in human performance and P200/N400 brain-electric data. Then, we present a sequential version of the AROM accounting for primed lexical decision, and the resulting semantic competition in the left (and right !) inferior frontal gyrus of the human brain. Finally, we envision two routes of reading, complementing the form-based aspects of linguistic representations with one of the most defining feature of words : they carry meaning.

24/11/2016 - LNC - Cédrick Florian (Centre de Recherches sur la Cognition Animale, Toulouse)

Cédrick Florian (Centre de Recherches sur la Cognition Animale, Toulouse)

24/11/2016 à 13:30
 

04/11/2016 - LPC - Hypnose, attention et imagination

    Vendredi 4 novembre 2016 - LPC
    11 heures, salle des Voûtes
    Alain Parra & Arnaud Rey
    Laboratoire de Psychologie Cognitive

Hypnose, attention et imagination

28/10/2016 - LPC - Learning reward uncertainty

     Vendredi 28 octobre 2016 - LPC
    11 heures, salle des Voûtes
    Rafal Bogacz
    Nuffield Department of Clinical Neurosciences
    University of Oxford

Learning reward uncertainty

To maximize their chances for survival, animals and humans need to base their decisions not only on the average consequences of chosen actions, but also on the variability of the rewards resulting from these actions. For example, when an animal’s food reserves are depleted, it should prefer to forage in an area where food is guaranteed over an area where the amount of food is higher on average but variable, thus avoiding the risk of starvation. To implement such policies, the animals need to be able to learn about variability of rewards resulting from taking different actions. This talk will present a simple mathematical model describing how such learning may be implemented in the basal ganglia. These models suggest how the information about reward uncertainty can be used during decision making, so that animals can make choices that not only maximize expected rewards but also minimize risks. The models account for a wide range of experimental data : from properties of individual dopaminergic receptors, to the effects of dopaminergic medications on choices involving risks, and they make multiple experimental predictions.

14/10/2016 - LPC - Introspection as decision

     Vendredi 14 octobre 2016 - LPC
    11 heures, salle des Voûtes
    Jérôme Sackur
    Laboratoire de Sciences Cognitives et Psycholinguistique
    Ecole Normale Supérieure Paris

Introspection as decision

An increasing number of studies in cognitive science make use of introspective responses. With the notable exception of confidence judgments, most of these responses are used as valid markers of subjective states, while their generative mechanisms are left unexplored. Here, drawing on two set of studies, I will make the case that the general framework of signal detection theory applies to introspections, as it applies to perceptions. First, I will present behavioral and pupillometric data from mind-wandering experiments suggesting that when participants are asked to report whether they are on-task or mind-wandering, they do so by comparing the level of an internal state variable with an adjustable criterion. Mental monitoring of mind-wandering thus exhibits a fundamental signature of signal detection. Second, I will focus on self-estimation of response times, as a specific case of self-observation. While it is known that participants can, with some limitations, report the speed of their own decisions, we don’t know how this is achieved. Here, by means of bayesian modeling of response times, I will show that the psychometric properties of these second order decisions are similar to those of first order decisions. Together, these findings converge on the notion that mental monitoring and self-observation can be modeled as inner or second order decisions. I will discuss the implications with respect to the functional significance of introspection.

10/10/2016 - LNC - Leslie Decker : Aging and reorganization of the neuromotor system : Insights from information processing and dynamical systems theoretical perspectives

Leslie Decker (Université de Caen)

Aging and reorganization of the neuromotor system : Insights from information processing and dynamical systems theoretical perspectives

When compensating for functional decline, the aging neuromotor system reorganizes and changes the complex cooperative interactions that occur within and between its subsystems. A first aspect of this reorganization is manifested through an increased attentional cost for controlling posture and gait. We performed a series of experiments using dual-task methodology for examining the extent to which depletion of attentional resources during normal aging constrains the use of motor abundance (i.e., solution strategies to perform any task reliably while being variable in movement’s particulars) and changes both the amount and structural complexity of motor variability. A second aspect of age-related functional reorganization is reflected by a larger cognitive permeation of the motor domain (i.e., increased interdependence between motor and cognitive processes), termed ‘dedifferentiation’. Through an investigation of the Fitts’ law and Hick-Hyman’s law, whose roots are in information theory, we demonstrated that dedifferentiation of cognitive and motor slowing becomes accentuated during pathological cognitive aging (i.e., mild cognitive impairment), particularly as the task at hand involves executive functions (i.e., Fitts’ aiming task with the non-preferred upper limb ; Hick-Hyman’s choice reaction time task with a spatial stimulus–response incompatible mapping). Taking advantage of the age-related dedifferentiation of cognitive and motor slowing, we showed evidence that the effects of processing speed training went beyond the trained (motor) domain, and transferred to the untrained (cognitive) domain (i.e., improved information processing efficiency and reduced decision-making errors). Taken together, these findings showed evidence that exploring the reorganization construct from different theoretical perspectives (i.e., theoretical integration) yielded insight into the age-related compensatory and adaptive processes related to motor control and the mediating role of processing speed (on which executive control relies) in the organization of goal-directed behaviors.

04/10/2016 - LPC - Expertise Research Contributions to Cognitive Aging : Examples from the Domain of Chess

     Mardi 4 octobre 2016 - LPC
    11 heures, salle des Voûtes
    Neil Charness
    Florida State University

Expertise Research Contributions to Cognitive Aging : Examples from the Domain of Chess

In this presentation I will outline a variety of approaches to understanding expertise. I’ll present a framework for examining how societal and individual factors influence skilled performance, then discuss growth curve analyses of skill acquisition functions, questionnaire approaches to assessing deliberate practice, experimental approaches to assessing pattern recognition processes, and a simulation model for examining trade-offs between knowledge and aging processes.