Séminaires des laboratoires

24/09/2018 - LNC - Daniele Schon (Institut de neurosciences des Systèmes, INSERM AMU)

Daniele Schon (Institut de neurosciences des Systèmes, INSERM AMU)

Changing scales for a changing science : Dynamiques des échelles de la science, une approche sémio-pheno-socio-economique

Quelles sont les échelles de la science ? Comment elles évoluent ? Quels sont les facteurs qui exercent une pression de sélection (à la Darwin) sur ces échelles ? Je donnerai quelques exemples pris de la littérature et de l’art pour montrer que les grandes échelles et les grands nombres ne sont pas nécessairement plus informative que les petites échelles et les petits nombres. Je montrerai ensuite quelques analyses quantitatives sur combien de temps il nous faut pour publier, combien nous publions, comment changent les supports de communication de la science, combien nous sommes, combien coûte la science, etc … Je ne suis pas un expert du domaine, mais je suis « tombé là-dedans » il y a quelques temps et je serai ravi de partager avec un publique de scientifiques avertis mes modestes connaissances et nombreuses questions qui émergent d’une telle réflexion. Suivra donc une discussion avec ceux qui ne seront pas pressé par temps.

 

21/09/2018 - LPC - SÉMINAIRE ILCB CHRISTIAN LORENZI

Salle des Voûtes, Campus St Charles - 11H - 13003 Marseille
Christian Lorenzi,
CNRS & Ecole normale supérieure, Paris,

Processing time with our auditory system

Debate on how speech information is represented in the auditory system has revolved around the role of two neural/perceptual features encoding the temporal modulations of the acoustic signal (the “temporal envelope”, ENV, and “temporal fine structure”, TFS), their relative contribution to intelligibility and how that might be degraded by lesions to the peripheral and central auditory system. We will review psychophysical studies that investigated the development of ENV/TFS perception, the effects of cochlear and central lesions, and the relationship between ENV/TFS perception and speech intelligibility. Our results suggest that: i) the processing of ENV and TFS is “functional” by 6 months, and fine-tuned by language exposure between 6 and 10 months, ii) ENV is more important for speech identification, whereas TFS is more important for the segregation of competing sound sources, iii) reduced ability to process ENV and/or TFS explains deficits typically associated with cochlear and central damage and ageing.

*References: *
Shamma, S., & Lorenzi, C. (2013). On the balance of envelope and temporal fine structure in the encoding of speech in the early auditory system. /Journal of the Acoustical Society of America, 133, /2818-2833/./
Lorenzi, C., Debruille, L., Garnier, S., Fleuriot, P., & Moore, B.C.J. (2009). Abnormal auditory temporal processing for frequencies where absolute thresholds are normal. /Journal of the Acoustical Society of America, 125, 27-30./
Lorenzi, C., Gilbert, G., Carn, H., Garnier, S., & Moore, B.C.J. (2006). Speech perception problems of the hearing impaired reflect inability to use temporal fine structure. /Proceedings of the National Academy of Science/ /USA/, /103(49)/, 18866-18869.
 

17/09/2018 - LNC - Serge Pinto (LPL, AMU CNRS)

Can we improve speech by subthalamic nucleus Deep Brain Stimulation (STN-DBS) in Parkinson’s disease?

Among the repertoire of motor dysfunctions that charaterize Parkinson's disease (PD), dysarthria denotes a motor speech disorder particularly disabling for individuals with PD. Dysarthria in PD is generally described by a monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice. Its responsiveness to treatments is often mitigated, and thus, the understanding and the management of dysarthria is still challenging for both researchers and clinicians. Notably, subthalamic nucleus deep brain stimulation (STN-DBS) enhances improvement of some motor components of speech production, while intelligibility decreases systematically after surgery. Results available often confirm the lower degree of speech improvement following STN stimulation compared with the global motor state, even demonstrating a potential exacerbation of speech deficits following stimulation. It has been suggested that PD dysarthria is associated with an altered recruitment of the principal brain motor regions (orofacial primary motor cortex, cerebellum) and an increased involvement of premotor and prefrontal cortices (notably the supplementary motor area). This pathological pattern does not parallel the compensatory strategy developed for segmentary motor tasks and may contribute to explain the frequent treatment discrepancies between limb and speech movements. This presentation aims at addressing the pathophysiology of dysarthria in PD, and discussing its characteristics from both neurophysiological and neurolinguistic points of view. Findings and issues related to the effects of STN-DBS on PD speech will also be adressed.

 

22/06/2018 - LPC - SÉMINAIRE GRÉGOIRE BORST

à définir
Grégoire Borst

Laboratoire de psychologie et du développement de l'enfant UMR8240
Université Sorbonne
Paris

Rôle du contrôle cognitif dans le développement cognitif et les apprentissages scolaires de l'enfant et de l'adolescent

Certains modèles du développement cognitif de l’enfant et de l'adolescent considèrent que la capacité à contrôler ses pensées, ses actions, ses stratégies et son impulsivité (contrôle cognitif et contrôle de soi) constitue un des mécanismes clefs du développement cognitif et scolaire de l'enfant d'âge pré-scolaire et d'âge scolaire et de l'adolescent. Nous présenterons les résultats d'un ensemble d'études dans différentes domaines cognitifs (nombre, catégorisation, raisonnement, prise de perspective, créativité) et différentes situations scolaires (résolution de problèmes arithmétiques, comparaison de nombres décimaux, comparaison de lettre) combinant des approches expérimentales et de neuroimagerie qui suggèrent que le contrôle cognitif pourrait être un mécanisme clef du développement dans ces différents domaines cognitifs et scolaires. Dans une deuxième partie du séminaire, nous présenterons les résultats d'un ensemble d'études en IRM anatomique, chez l'enfant et l'adulte, qui suggèrent que la variabilité interindividuelle observée dans différents fonctions cognitives (contrôle cognitif, lecture et cognition numérique) est en partie liée à des contraintes cérébrales précoces, déterminées in utero et stables au cours du développement (i.e., motifs sulco-gyraux).

01/06/2018 - LPC - SÉMINAIRE PASCAL MAMASSIAN

LPC, Salle des Voûtes, Campus St Charles - 13003 Marseille
Pascal Mamassian, PhD
Laboratoire des Systèmes Perceptifs (CNRS UMR 8248)
Ecole Normale Supérieure - 11h

Ideal and super-ideal confidence observers

Visual confidence refers to our ability to predict the correctness of our perceptual decisions. Knowing the limits of this ability, both in terms of biases (e.g. overconfidence) and sensitivity (e.g. blindsight), is clearly important to approach a full picture of perceptual decision making. The measurement of visual confidence with the classical method of confidence ratings presents both advantages and disadvantages. In recent years, we have explored an alternative paradigm based on confidence forced-choice. In this paradigm, observers have to choose which of two perceptual decisions is more likely to be correct. I will review some behavioural results obtained with the confidence forced-choice paradigm. I will also present two ideal observers based on signal detection theory, one that uses the same information for perceptual and confidence decisions, and another one that has access to additional information for confidence. These ideal observers help us quantify the limitations of human confidence estimation.

25/05/2018 - LPC - SÉMINAIRE RANI MORAN

LPC, salle CH57, Campus St Charles - 13003 Marseille
Rani Moran
University College London | UCL · Wellcome Trust Centre for Neuroimaging

Retrospective Model-Based Inference Guides Model-Free Credit Assignment

To adapt to their environments, organisms need to learn which actions are rewarding in different states of the world. Extensive research in Reinforcement Learning (RL) has shown that organisms cope efficiently with this credit-assignment problem, even when their actions are executed under challenging conditions of action and/or state uncertainty. However, little is known about such credit-assignment even for the common case where this uncertainty is subsequently resolved. Such is the case, for example, when you ask for a salary-raise without knowing whether your employer is in a good or a bad mood and a few days later you learn that she was in a bad mood when she approved your request. Does this knowledge modulate your credit assignment? Here, I will examine this question from the perspective of the interaction between habitual (model-free; MF) and goal-directed (model-based; MB) systems. Whereas previous research in RL has mostly focused on an MB prospective-planning function, I will present a novel theory of MB retrospective-inference and an experimental test of this theory based on a novel bandit task. According to our theory, an MB system resolves the uncertainty that prevailed when actions were taken and hence guides MF credit-assignment. In support of our theory, we found that when subject’s momentary uncertainty about which bandit had generated an outcome was resolved by subsequent information, they assigned most of the credit to the bandit they inferred to have been responsible. I will discuss how these findings enrich our knowledge on the variety of MB functions and the scope of MB-MF interactions.

20/02/2018 - LNIA - Mécanismes cérébraux de la rémission dans le Trouble de Stress Post-Traumatique

Dr. Stéphanie Khalfa, INT Marseille

invitée par B. Alescio-Lautier

Le mardi 20 février 2018 de 11h à 12h

 

12/02/218 - LNC - Jérémie Gaveau (Université de Bourgogne, Dijon)

Sensorimotor integration of gravity : what can we learn from arm movements ?

It is well acknowledged that the motor system anticipates forthcoming dynamics. Although the CNS is thought to build an internal model of gravity, opposed theories exist on the question of how the motor system uses this model to plan a movement. One theory proposes that the motor system compensates gravity effects and uses scaling laws to simplify movement control. Another theory suggests that the motor system uses gravity effects in order to minimize effort. I will present the results of several experiments in which single-joint arm movements have been investigated in healthy humans, in patients and in non-human primates. Our results support the idea that the motor system implements sophisticated strategies taking advantage of movement dynamics.

 

12/02/2018 à 13:30

 

 

09/02/2018 - LPC - Séminaire James H. Smith-Spark

Executive functioning in adults with dyslexia

Abstract

While developmental dyslexia is characterised typically by problems with reading and spelling, difficulties in other areas of cognition have also been found. Executive functioning is one such area. Deficits are well documented in children with dyslexia. There is also evidence showing that these executive functioning problems persist into adulthood and, consequently, can have implications for success in education and employment. In this seminar, laboratory evidence from a range of studies conducted by the author will be considered, together with research exploring the day-to-day impact of dyslexia on executive functioning. Beginning with the role of executive processes in visuospatial working memory, the author will present evidence for executive functioning deficits in adults with dyslexia across discrete executive functions (updating, set shifting, inhibition, and verbal fluency). Self-report evidence relating to typical, everyday executive functioning will also be considered. The nature of the results presents challenges to dyslexia theory to explain, particularly where executive functioning deficits have been found on tasks which have minimal phonological processing requirements. The results from the author’s studies will thus be related to dyslexia theory and, more particularly, the proposition that there is a Supervisory Attentional System deficit in dyslexia.

 

Date: Vendredi, 9 février, 2018 - 11:00
Date fin: Vendredi, 9 février, 2018 - 13:00
Lieu: LPC, Salle des Voûtes, Campus St Charles - 13003 Marseille

 

26/01/218 - LPC - Séminaire Mathias Pessiglione

Mathias Pessiglione

Motivation, Brain and Behavior (MBB) team, Institut du Cerveau et de la Moelle (ICM) 
Hôpital de la Pitié-Salpêtrière, Paris, France

How to resist temptation: the dangers of executive fatigue

The capacity to resist temptation of immediate pleasures is a major factor of social insertion and professional success. This self-control capacity is critical in inter-temporal choices, where immediate rewards are opposed to bigger but delayed rewards. Recent studies have suggested that resisting temptation requires the intervention of a prefronto-parietal system classically involved in executive control. In this talk, I will provide evidence that the executive control system is susceptible to fatigue, after periods of intense mobilization that range from hours to weeks. Executive fatigue is associated with reduced activity in the lateral prefrontal cortex during decision making, and results in more impulsive inter-temporal choices – a greater propensity to favor immediate rewards over long-term goals.

Date: Vendredi, 26 Janvier, 2018 - 11:00
Date fin: Vendredi, 26 Janvier, 2018 - 13:00
Lieu: LPC, Salle des Voûtes, Campus St Charles - 13003 Marseille

 

2017/12/08 - LPC - Séminaire Irène Altarelli


 
Cognitive determinants of learning in the auditory and the visual domains

Superior performance can be induced through practice in a variety of training domains. However, a major limitation for intervention purposes – be they educational or clinical – is that the resulting behavioural enhancements rarely extend beyond the practiced task, thus limiting the impact of interventions to real-life contexts. In the series of experiments presented here, we explore learning and generalization in both the visual and the auditory domain. In one study, we describe a novel paradigm aimed at probing the extraction and transfer of a given structure across tasks. Furthermore, we take an individual differences approach to determine the resources that may specifically contribute to this type of structure learning. Our results identify a subset of our participants that are able to exploit the common structure across tasks and attain exceptionally high performance levels. Among other factors, structure learning abilities correlate positively with two main factors – attentional control and years of education. In a second study, we explore learning and generalization of audio-visual associations, again uncovering a link with attentional control. While we replicate and extend the results of many studies indicating a link between executive functions and learning, the contribution of years of education suggests that prior experience with extracting patterns might play an important role.

Date: Vendredi, 8 Décembre, 2017 - 11:00
Date fin: Vendredi, 8 Décembre, 2017 - 13:30
Lieu: Campus St Charles, Salle CH56 du bâtiment 7

Irène Altarelli
University of Geneva , Genève

16/10/2017 - LNC - Rochelle Ackerley (Laboratoire de Neurosciences Intégratives et Adaptatives, Marseille)

Rochelle Ackerley (Laboratoire de Neurosciences Intégratives et Adaptatives, Marseille)

Stimulating single tactile afferents in humans : sensations felt and cortical responses generated

Our touch system presents a complex network of afferents, where a multitude of sensations can be felt, from more simple facets like vibration to blended percepts such as wetness. The technique of microneurography permits recordings from single human afferents, via the insertion of an electrode into a peripheral nerve. Mechanical stimuli can be applied to the skin and the responses from tactile afferents can be recorded. This can be taken one step further, by recording from a single afferent and then stimulating the same one, by applying a small electrical current down the electrode. In essence, it is possible to record signals from one mechanoreceptive afferent, then artificially stimulate it to produce a perceptual tactile experience, where questions can be asked about the illusory sensation generated. I combine this approach with high resolution brain imaging, to understand the precise somatosensory circuits that encode such fundamental touch. These findings can be applied in the domain of emulating cutaneous signals, such as recovering touch in amputees. The implementation of somatosensory feedback for missing body parts represents an immense step forward in the development and use of prostheses.

16/10/2017 à 13:30

13/10/2017 - LNC - Séminaire Emmanuel Barbeau

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

Emmanuel Barbeau
Centre de Recherche Cerveau et Cognition, UMR5549, Toulouse, France

Familiarity and recollection: revisiting dogmas

We recognize everyday dozens of objects and faces. Actually this ability is so efficient that we do not even pay any attention to it. However, it has been shown that we can rapidly store thousands of new pictures and sometimes for a very long time without rehearsal in the meantime. Phenomenologically two processes are supposed to participate to recognition memory, one fast and acontextual called familiarity, the other slower and associated with the context in which the stimulus was encountered called recollection. Although there is agreement on the core network of brain regions involved in recollection, surprisingly little is known about familiarity, quite probably because the psychological and physiological signals associated with familiarity are fast, but also much weaker, than those associated with recollection. In fact, it is not even clear if familiarity is a single process as often presented. In this talk, I will review recent studies in which we used a combination of new paradigms, neuropsychological and intracerebral electrophysiological studies to identify the network of brain regions involved in familiarity.

06/10/2017 - LPC - Séminaire George Michael

 

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

George Michael
Université Lumière, Lyon 2

29/09/2017 - LPC - Séminaire Corentin Gonthier

Séminaire Corentin Gonthier

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

Corentin Gonthier
MCF en psychologie différentielle et statistiques
LPE - CRPCC Université Rennes 2

Un contrôle cognitif sans fonctions exécutives : la variabilité selon le modèle à deux mécanismes de contrôle (DMC)

L'aptitude des individus à réguler leur comportement est souvent étudiée sous l'angle des fonctions exécutives : des fonctions élémentaires comme l'inhibition ou la flexibilité. Mais une autre approche consiste à définir le contrôle cognitif comme une aptitude relativement unitaire, ce qui ouvre la voie à des recherches portant sur la façon dont ce contrôle est mis en place. Le modèle à deux mécanismes de contrôle (DMC : Braver et al., 2007) propose par exemple que le contrôle cognitif peut se faire de façon proactive ou de façon réactive.
Je présenterai cette approche originale du contrôle cognitif et une série de travaux portant sur la mesure des mécanismes de contrôle proactif et réactif, la possibilité d'induire les participants à utiliser l'un des deux mécanismes, et leur lien avec la capacité en mémoire de travail.

26/09/2017 - LNIA - “Involvement of the thalamic nucleus réunies in the hippocampo-cortical coupling”

Dr. Pascale Quilichini, Institut de Neurosciences des Systèmes, PhysioNet Team, INSERM U1106

“Involvement of the thalamic nucleus réunies in the hippocampo-cortical coupling”
mardi 26 septembre 2017, de 11h à 12h (invité par JL. Blanc).