Camille-Aimé Possamaï

Aix-Marseille Université, Marseille, Provence-Alpes-Cote d'Azur, France

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Publications (17)40.49 Total impact

  • Thierry Hasbroucq, Boris Burle, Franck Vidal, Camille-Aime Possamaï
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    ABSTRACT: In a common version of the Simon task, the subjects respond by a left- or a right-hand key press to the color of a stimulus (S) presented to the left or right of a fixation point. Albeit S location is irrelevant, the incorrect response is more often activated when the required response is contralateral to the S (incongruent) than when it is ipsilateral to the S (congruent). The aim of the present study was to decipher the respective contributions of S-response key location correspondence and S-hand correspondence to such incorrect activations (IAs). The subjects were required to perform a Simon task with the arms not crossing and crossing the median plane. Present for both arm placements, the difference in the frequency of IAs between incongruent and congruent responses was smaller when the arms were crossed. IAs are (i) essentially due to S-key location correspondence and (ii) less influenced by S-hand correspondence. Latency analyses further suggest that intra-hemispheric processing mediates the influence of S-hand correspondence.
    Psychophysiology 08/2009; 46(6):1160-9. · 3.29 Impact Factor
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    ABSTRACT: In between-hand choice reaction time tasks, the motor cortex involved in the required response is activated while the motor cortex involved in the non-required response is inhibited. Such an inhibition could be implemented actively between the responses defined as possible alternatives by the task instructions or, alternatively, could passively result from some kind of "reciprocal inhibition" between the two motor cortices. The present study addressed this issue. To this end, we compared the surface Laplacian transforms of electroencephalographic (EEG) waves recorded over the contralateral and ipsilateral motor cortices in between-hand and within-hand choice conditions. The dynamics of the recorded EEG activities suggest that inhibition is implemented in a feed-forward manner between the cortical zones controlling the different response alternatives rather than between homologous motor cortical structures.
    Psychophysiology 05/2009; 46(4):726-30. · 3.29 Impact Factor
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    ABSTRACT: Nitrous oxide (N(2)O) inhalation, at subanaesthetic concentrations, impairs choice reaction time (RT). However, the functional locus of this effect remains to be ascertained. In the present study, this issue was investigated by applying the additive factor logic to the RTs of rats performing a visuo-motor task. The task consisted of either a left-side or a right-side body displacement to a visual stimulus displayed in either the left or right hemispace. The experimental design involved the manipulation of two task factors (stimulus luminance and foreperiod duration) the effects of which are additive on RT. Inhaled N(2)O (from 0% to 60%) was varied as the third factor of the design. N(2)O prolonged RT in a dose-dependent manner and this effect was additive with that of stimulus luminance, whilst it interacted with that of foreperiod duration. Moreover, at low concentrations (10-20%), N(2)O abolished the effect of foreperiod, possibly through a disturbance of time estimation processes, whereas at higher concentrations (30-40%) N(2)O enhanced the effect of foreperiod, probably by slowing down motor processes. Movement time (MT) was decreased by N(2)O at 20-40%. The present data provide evidence that N(2)O impairs information processing by altering at least the stage of motor adjustment. In addition, N(2)O spares the sensory processes implemented during the stimulus preprocessing stage. A subsidiary result is that at some concentrations, N(2)O displays opposite effects on reaction time and movement time. These results demonstrate that the additive factor method constitutes a powerful new tool for studying the pharmacology of information processing in animal models.
    Psychopharmacology 03/2003; 165(4):321-8. · 4.06 Impact Factor
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    ABSTRACT: Recently, we have shown that oral absorption of levodopa shortens reaction time (RT), measured as the interval between the response signal and the onset of voluntary electromyographic (EMG) activity. The motor time (MT) interval that elapses from the EMG activity to the mechanical response was not analysed. The purpose of the present study was to analyse the effect of the dose of levodopa administrated in our previous study on the MT. Eight healthy adults (aged 21-28, mean=25), performed a two-choice visual RT task after oral absorption of a single dose of levodopa (200 mg) or a placebo (randomized, double-blind, cross-over design). Like RT, MT was shorter under levodopa than under placebo. Statistical analyses demonstrated that this effect was present for all deciles of the RT and MT distributions. Levodopa shortens not only RT but also MT, which points at the implication of the dopaminergic system in both premotor and motor processes.
    Psychopharmacology 02/2003; 165(3):313-6. · 4.06 Impact Factor
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    ABSTRACT: Manual responses to lateralized stimuli are faster for spatially congruent stimulus-response associations than for incongruent associations, even if the stimulus location is irrelevant. This effect, however, decreases as reaction time increases. Recent data suggest that such a decrease reflects online, within-trial executive control. The present study was aimed at testing this hypothesis by analyzing the electromyographic activity of muscles involved in response execution. We focused on the particular trials in which an activation of the muscle involved to the incorrect response preceded the execution of the correct response. A sequential effect analysis, along with an analysis of the reaction time distributions, revealed that after such dual-activation trials, executive control was reinforced. In addition, a distribution analysis of the reaction times associated with such trials compared to the trials without incorrect activation, revealed online, within-trial changes in executive control. Arguments against a late motor locus of the effect of the irrelevant stimulus location are also provided. These results are discussed in terms of current models of cognitive control.
    Psychological Research 12/2002; 66(4):324-36. · 2.47 Impact Factor
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    ABSTRACT: Dopamine is involved in a variety of motor and non-motor information-processing operations. One way to determine its contribution to human information processing is to study reaction time (RT) performance after oral absorption of its precursor, levodopa, which increases its concentration in the nervous system. The purpose of the present study was to investigate the effect of a single dose of levodopa on information processing in healthy human subjects using the additive-factor method. After oral absorption of a single dose of levodopa (200 mg) or a placebo (randomized, double-blind, cross-over design), eight adults (aged 21-28 years, mean 25 years) performed a two-choice visual RT task. Signal intensity, stimulus-response mapping and foreperiod duration were manipulated. The effects of these three variables were found additive on RT, indicating that that three independent stages - namely, stimulus preprocessing, response selection and motor adjustment - were manipulated. Levodopa improved RT performance in a specific way: it interacted with signal intensity but its effect was additive with those of stimulus-response mapping and foreperiod duration. These results show that levodopa specifically affects the stimulus preprocessing stage, which suggests that the dopaminergic system plays a role in sensory processing, possibly by acting on the level of arousal.
    Psychopharmacology 09/2002; 163(1):62-7. · 4.06 Impact Factor
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    Camille-Aimé Possamaï, Borís Burle, Allen Osma, Thierry Hasbroucq
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    ABSTRACT: We present evidence that advance information reducing the number of stimulus-response alternatives in a choice reaction time (RT) task can shorten the very latest motoric stages of RT. Effects of such advance information on late stages of RT have been demonstrated recently by Osman, Moore, and Ulrich (Acta Psychol. 90 (1995) 111), Leuthold, Sommer, and Ulrich (J. Exp. Psychol: Gen. 125 (1996) 307), Müller-Gethmann, Rinkenauer, Stahl, and Ulrich (Psychophysiology 37 (2000) 507). These studies found that advance information shortens the portion of the RT interval following onset of a movement-related brain potential (lateralized readiness potential). Osman et al. and Müller-Gethmann et al. also examined the portion of the RT interval following the start of electromyographic (EMG) activity and found no effect of advance information. Based on Osman et al.'s null result, Leuthold et al. speculated that advance information may shorten only the RT stages preceding EMG activity. This conclusion, however, is questionable because of limitations in the EMG measures employed by both Osman et al. and Müller-Gethmann et al. We have reanalyzed the results of a previously reported experiment (Acta Psychol. 101 (1999) 243) to show that advance information can in fact affect the rate of recruitment of motor units in the prime mover of the responding limb.
    Acta Psychologica 08/2002; 111(1):125-39. · 2.26 Impact Factor
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    ABSTRACT: Abstract Rationale. Dopamine is involved in a variety of motor and non-motor information-processing operations. One way to determine its contribution to human information processing is to study reaction time (RT) performance after oral absorption of its precursor, levodopa, which increases its concentration in the nervous system. Objective. The purpose of the present study was to investigate the effect of a single dose of levodopa on information processing in healthy human subjects using the additive-factor method. After oral absorption of a single dose of levodopa (200mg) or a placebo (randomized, double-blind, cross-over design), eight adults (aged 21–28years, mean 25years) performed a two-choice visual RT task. Signal intensity, stimulus-response mapping and foreperiod duration were manipulated. Results. The effects of these three variables were found additive on RT, indicating that that three independent stages – namely, stimulus preprocessing, response selection and motor adjustment – were manipulated. Levodopa improved RT performance in a specific way: it interacted with signal intensity but its effect was additive with those of stimulus-response mapping and foreperiod duration. Conclusion. These results show that levodopa specifically affects the stimulus preprocessing stage, which suggests that the dopaminergic system plays a role in sensory processing, possibly by acting on the level of arousal.
    Psychopharmacology 07/2002; 163(1):62-67. · 4.06 Impact Factor
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    ABSTRACT: In the field of sensorimotor activities, progresses achieved over the last fifty years have been largely driven by the Reaction Time (RT) paradigm. Information processing models are set in the context of a global breakdown of sensorimotor activities in multiple concatenated stages, each aggregated in many fundamental operations that are functionally linked. If there is a consensus today about this breakdown, the way stages organize themselves in time however is still much debated. According to one hypothesis, there is no temporal overlap between each stages: the process occurs sequentially. According to another theory, the stages overlap over in time: the process occurs in a parallel manner. A behavioral analysis does not allow to determine between these two hypothesis because the RT represents the final product of the whole sensorimotor pathway, while the temporal organization of the processing of information depends on the nature of the transfer between individual stages. An all-or-nothing information transfer, also called discrete, leads to a sequential organization, while a progressive or continuous transfer brings about a parallel organization. Moreover, contrary to a preconceived notion, data obtained from classical neurophysiology are compatible with both a sequential organization and a parallel organization. Particularly, the great number of connections between the different elements of the nervous system has often seemed difficult to conciliate with a sequential organization. In fact, this argument is inadmissible because it stems from confusion between a temporal organization and an anatomical organization of the processing of information. More generally, our knowledge of the functional anatomy of sensorimotor activities imposes but few constraints on the temporal organization patterns of the processing of information. The lack of interest for the neurophysiological argument seems essentially due to the fact that theses arguments rest on research which is not aimed at the temporal organization of the sensorimotor information processing. Recently, approaches that integrate concepts and methods used in experimental psychology and neurosciences have contributed to putting in perspective the organization of information processing. Electromyography, EEG, reflexology and neuronal recording techniques have been used in the context of two inference logics. The first logic, that we call "factual", is based on the study of functional relations between RT and certain neuronal events. The second logic, that we call "chronometric", is based on the study of the relationships between RT and intervals resulting from the breakdown of the RT in relation to certain neuronal events. Generally speaking, most studies suggest that in tasks where the stimulus is composed of numerous attributes, information processing operates in parallel. On the other hand, when the stimulus is made up of a single attribute, information processing could be operating in a sequential manner. One weakness of this electrophysiological approach is that it has so far only examined relationships between physiological indicators and means RT. We propose here to offset these weaknesses by examining functional relationships between RT distribution variances and certain neuronal events linked to information processing.
    Canadian Journal of Experimental Psychology 07/2002; 56(2):75-97. · 1.02 Impact Factor
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    ABSTRACT: The present study was aimed at deciphering whether the delay in choice reaction time (RT) and the silent period (SP) caused by transcranial magnetic stimulation (TMS) of the motor cortex in the ongoing electromyogram are due to the same physiological mechanism. To this end, the effect of TMS was studied in 6 healthy volunteers performing a between-hand choice RT task. Specific predictions were derived from a logic inspired from the "postponed stages" hypothesis (Pashler & Johnson, 1989). This logic predicts a correlation between SP duration and RT when the stimulated cortex is involved in the response, and a stronger correlation when the stimulation is delivered later during the RT interval. The effect of TMS on RT was twofold: At early stimulation times, the stimulation shortened the RT and this effect was independent of the involvement of the stimulated motor cortex in the subsequent response. At later stimulation times, TMS had a disruptive effect, provided that the stimulated cortex was involved in the response. When the stimulated cortex was involved in the response, there was a correlation between SP and RT; this correlation was stronger when the stimulation occurred later. In contrast, there was no correlation between these two variables when the stimulated cortex was not involved.
    Psychophysiology 04/2002; 39(2):207-17. · 3.26 Impact Factor
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    ABSTRACT: In the field of sensorimotor activities, progress achieved over the last 50 yrs have been largely driven by the Reaction Time (RT) paradigm. Contrary to a preconceived notion, data obtained from classical neurophysiology are compatible with both a sequential organization and a parallel organization. Electromyography, EEG, reflexology and neuronal recording techniques have been used in the context of two inference logics. The first logic is based on the study of functional relations between RT and certain neuronal events. The second logic is based on the study of the relationships between RT and intervals resulting from the breakdown of the RT in relation to certain neuronal events. Most studies suggest that in tasks where the stimulus is composed of numerous attributes, information processing operates in parallel. However, when the stimulus is made up of a single attribute, information processing could be operating in a sequential manner. One weakness of this electrophysiological approach is that it has so far only examined relationships between physiological indicators and means RT. The authors propose here to offset these weaknesses by examining functional relationships between RT distribution variances and certain neuronal events linked to information processing. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
    Canadian Journal of Experimental Psychology-revue Canadienne De Psychologie Experimentale - CAN J EXP PSYCHOL. 01/2002; 56(2):75-97.
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    ABSTRACT: Dans le domaine des activités sensorimotrices, les progrès réalisés depuis les années cinquante sont largement tributaires du paradigme de temps de réaction ( TR ). Les modèles du traitement de l’information s’inscrivent dans le cadre d’une décomposition globale des activités sensorimotrices en plusieurs étapes concaténées regroupant chacune plusieurs opérations élémentaires fonctionnellement liées. Si cette décomposition fait aujourd’hui l’objet d’un consensus, la façon dont les étapes s’organisent dans le temps est l’objet d’un débat. Selon une première hypothèse, il n’existe pas de recouvrement temporel entre les différentes étapes : le traitement s’opère de façon séquentielle. Selon une hypothèse alternative, les étapes se recouvrent dans le temps : le traitement s’opère de façon parallèle. L’analyse comportementale ne permet pas de trancher entre ces deux hypothèses car le TR représente le produit final de l’ensemble de la chaîne sensorimotrice, tandis que l’organisation temporelle du traitement de l’information dépend des propriétés de la transmission entre étapes individuelles. Une transmission d’information en tout ou rien, encore appelée discrète, conduit à une organisation séquentielle tandis qu’une transmission progressive, ou continue, conduit à une organisation parallèle. Par ailleurs les données issues de la neurophysiologie classique sont aussi compatibles avec une organisation séquentielle qu’avec une organisation parallèle. En particulier, le grand nombre de connexions entre les différents éléments du système nerveuxa souvent semblé difficile à concilier avec une organisation séquentielle. Cet argument n’est en fait pas recevable car il repose sur une confusion entre l’organisation temporelle et l’organisation anatomique du traitement de l’information. Plus généralement, contrairement à une idée reçue, notre connaissance de l’anatomie fonctionnelle des activités sensorimotrices impose peu de contraintes sur les modèles d’organisation temporelle du traitement de l’information. Le peu d’intérêt des arguments neurophysiologiques semble essentiellement imputable au fait que ces arguments reposent sur des travaux dont l’objet n’est pas l’organisation temporelle du traitement de l’information sensorimotrice. Récemment, des approches intégrant les concepts et les méthodes de la psychologie expérimentale et des neurosciences ont contribué à éclairer l’organisation du traitement de l’information. Les techniques d’électromyographie, d’électroencéphalographie, de réflexologie et d’enregistrement neuronal unitaire ont été mises en œuvre dans le cadre de deux logiques d’inférence. La première logique, que nous appelons « événementielle », repose sur l’étude des relations fonctionnelles entre le TR et certains événements neuraux. La seconde logique, que nous appelons « chronométrique », repose sur l’étude des relations entre le TR et les intervalles résultant de la décomposition du TR par rapport à certains événements neuraux. L’ensemble des travaux réalisés suggèrent que dans les tâches où le stimulus est composé de plusieurs attributs, le traitement de l’information s’opère en parallèle. En revanche, quand le stimulus est composé d’un seul attribut, le traitement de l’information pourrait s’opérer de façon séquentielle. Une faiblesse de cette approche éléctrophysiologique est de n’avoir jusqu’ici envisagé que les relations entre indices physiologiques et le TR moyen. Nous proposons ici de pallier cette faiblesse en examinant les relations fonctionnelles entre les variances des distributions de TR, et certains événements neuraux liés au traitement de l’information. Depuis les travaux de Donders (1868) sur la ‘vitesse des actes psychiques’, de très nombreuses recherches ont été consacrées à l’étude de la dynamique du traitement de l’information. Traditionnellement, cette dynamique est étudiée dans le cadre du paradigme de temps de réaction ( TR ). Toutefois, les études comportementales réalisées à ce jour n’ont pas permis de révéler cette dynamique. Dans cet article, après avoir présenté le cadre théorique et empirique général de cette approche, nous résumerons les principaux arguments comportementaux recueillis dans ce cadre et nous montrerons leur insuffisance. Nous indiquerons ensuite les raisons pour lesquelles les données de la neurophysiologie classique ne permettent pas d’éclairer la dynamique du traitement de l’information. Afin de pallier les insuffisances des données comportementales et neurophysiologiques, de nouvelles approches combinant méthodes psychologiques et techniques provenant du champ des neurosciences ont été élaborées. L’ensemble des travaux réalisés dans ce cadre obéissent à deux logiques distinctes que nous qualifierons respectivement d’événementielle et de chronométrique. Dans cet article, nous expliciterons chacune de ces logiques et nous résumerons les résultats auxquels elles ont conduit. La principale faiblesse de cette approche psychophysiologique semble tenir à ce que les différents travaux réalisés à ce jour n’ont envisagé que les relations entre indices physiologiques et le TR moyen obtenu dans chaque condition expérimentale. Cette pratique pouvant conduire à des conclusions erronées quant à la nature séquentielle ou parallèle de l’architecture cognitive, nous proposerons de développer l’approche psychophysiologique en examinant les relations fonctionnelles entre les moyennes et les variances des distributions de TR, d’une part, et de certains événements neuraux liés au traitement de l’information, d’autre part.
    Canadian Journal of Experimental Psychology-revue Canadienne De Psychologie Experimentale - CAN J EXP PSYCHOL. 01/2002; 56(2):75-97.
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    ABSTRACT: Ketamine is an N-methyl-D-aspartate antagonist that induces cognitive dysfunctions. The purpose of the present study was to investigate the effects of a subanesthetic dose of ketamine on human information processing, using the additive factor method. During perfusion of a subanesthetic dose of ketamine (0.5 mg/kg over 60 min) or a placebo (randomized double-blind, cross-over design), eight adults (aged 22-33, mean=27) performed a two-choice visual reaction time (RT) task. Signal intensity, stimulus-response mapping, and foreperiod duration were manipulated. The effects of these three variables were found to be additive on RT, indicating that three independent stages - namely, stimulus preprocessing, response selection and motor selection- were manipulated. Ketamine altered RT performance in a specific way: it interacted with foreperiod duration but its effect was additive with those of signal intensity and stimulus-response mapping. These results show that ketamine specifically affects the stage of motor adjustment, which suggests that the glutamatergic system plays an important role in motor processes.
    Neuroscience Letters 05/2001; 303(1):29-32. · 2.03 Impact Factor
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    ABSTRACT: The aim of the present study was to assess levodopa (L-Dopa)-induced drowsiness in healthy volunteers using two parameters: choice reaction time and a subjective rating of sedation. Sixteen subjects participated in a randomized, double-blinded, crossover study. A single dose of 200 mg L-Dopa or placebo was administered at 9:00 AM. To limit peripheral side effects connected with L-Dopa, subjects were treated with 20 mg domperidone three times daily. Subjective rating of sedation consisted of visual analogue scale. Reaction time was measured by means of responses to two light-emitting diodes. The illumination of one of these diodes constituted the imperative signal. Manual responses were performed on two buttons located under the right and left index fingers. Results demonstrated a positive correlation between sedation level and reaction time (r = 0.70, p = 0.0026). Adverse events of L-Dopa were nausea (four cases) and excitation (one case). Subjects who did not develop adverse events were faster under L-Dopa than under placebo (p = 0.02), whereas subjects who had nausea or excitation were slower. A single dose of L-Dopa either deteriorated or improved choice reaction time in healthy volunteers according to whether it was sedative and whether it generated disruptive adverse events.
    Clinical Neuropharmacology 01/2001; 24(2):91-4. · 1.82 Impact Factor
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    ABSTRACT: The activity of the agonist muscles was recorded during the performance of a two-choice visual reaction time (RT) task in which the compatibility of the stimulus–response mapping was manipulated. Correct trials were distinguished according to whether or not the activation of the agonist of the required response was preceded by an activation of the agonist of the nonrequired response. Double activation trials were more numerous for the incompatible than for the compatible mapping. Furthermore, these trials yielded longer RTs than the single muscular activation trials. These results suggest that initial activations of nonrequired responses are more frequently aborted and corrected when the mapping is incompatible than when it is compatible. This finding supports the dimensional overlap model of stimulus–response compatibility (S. Kornblum, T. Hasbroucq, & A. Osman, 1990).
    Psychophysiology 12/2000; 38(1):157 - 162. · 3.29 Impact Factor
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    ABSTRACT: Sternberg introduced the additive factor method as a tool for discovering and studying in choice reaction time situations in human subjects. Underlying the method is the notion that if information processing consists of successive stages, then different factors affecting different stages must have additive effects on reaction-time measurements. The additive factor method has been extensively used in humans but few attempts have been made to examine whether or not additive reaction time patterns were obtainable in rats. In the present work, the subjects (13 Long-Evans rats) had to press down a lever and to respond to a visual (right or left) stimulus by releasing the lever and introducing the head into a lateral (right or left) operandum. The present findings show an additive pattern of effects of signal luminance and foreperiod duration on the mean reaction time which suggests that we have successfully manipulated two stages of rat information processing - the preprocessing stage and the motor adjustment stage, respectively. Accordingly, the present study sets the basis for the basis for investigating the effects of invasive manipulations (pharmacological and/or lesional) on information processing stages.
    Behavioural processes 09/2000; 50(2-3):113-121. · 1.53 Impact Factor
  • Thierry Hasbroucq, Camille-Aimé Possamaï
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    ABSTRACT: Contrary to traditional conceptions, Stoffels, Van der Molen and Keuss (1989) and Hasbroucq and Guiard (1991) have proposed that the Simon effect reflects the processes of stimulus identification rather than those of response selection. In a recent issue of the journal, this new hypothesis was challenged by Proctor, Lu and Van Zandt (1992) on the basis of results showing that the Simon effect can be enhanced by precuing procedures. In the present paper, the evidence gathered by Proctor et al. is closely examined and a new analysis reveals that the data presented support rather than invalidate an explanation of the Simon effect in terms of stimulus identification mechanisms.
    Acta Psychologica. 01/1994; 85(3):235-244.

Publication Stats

234 Citations
40.49 Total Impact Points

Institutions

  • 2009
    • Aix-Marseille Université
      • Laboratoire de Neurobiologie de la Cognition (UMR 7291)
      Marseille, Provence-Alpes-Cote d'Azur, France
  • 1994–2009
    • French National Centre for Scientific Research
      • Centre de Recherches sur la Cognition et l'Apprentissage
      Lutetia Parisorum, Île-de-France, France
  • 2002–2003
    • Université de Poitiers
      • Maison des Sciences de l’Homme et de la Société
      Poitiers, Poitou-Charentes, France