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Dive into the research topics where Christelle Lemoine is active.

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Featured researches published by Christelle Lemoine.


PLOS ONE | 2012

Effect of a Dual Task on Postural Control in Dyslexic Children

Agathe Legrand; Emmanuel Bui-Quoc; Karine Doré-Mazars; Christelle Lemoine; Christophe Loı̈c Gérard; Maria Pia Bucci

Several studies have examined postural control in dyslexic children; however, their results were inconclusive. This study investigated the effect of a dual task on postural stability in dyslexic children. Eighteen dyslexic children (mean age 10.3±1.2 years) were compared with eighteen non-dyslexic children of similar age. Postural stability was recorded with a platform (TechnoConcept®) while the child, in separate sessions, made reflex horizontal and vertical saccades of 10° of amplitude, and read a text silently. We measured the surface and the mean speed of the center of pressure (CoP). Reading performance was assessed by counting the number of words read during postural measures. Both groups of children were more stable while performing saccades than while reading a text. Furthermore, dyslexic children were significantly more unstable than non-dyslexic children, especially during the reading task. Finally, the number of words read by dyslexic children was significantly lower than that of non-dyslexic children and, in contrast to the non-dyslexic children. In line with the U-shaped non-linear interaction model, we suggest that the attention consumed by the reading task could be responsible for the loss of postural control in both groups of children. The postural instability observed in dyslexic children supports the hypothesis that such children have a lack of integration of multiple sensorimotor inputs.


Investigative Ophthalmology & Visual Science | 2012

Are There Any Left-Right Asymmetries in Saccade Parameters? Examination of Latency, Gain, and Peak Velocity

Dorine Vergilino-Perez; Alexandra Fayel; Christelle Lemoine; Patrice Senot; Judith Vergne; Karine Doré-Mazars

PURPOSE Hemispheric specialization in saccadic control is still under debate. Here we examine the latency, gain, and peak velocity of reactive and voluntary leftward and rightward saccades to assess the respective roles of eye and hand dominance. METHODS Participants with contrasting hand and eye dominance were asked to make saccades toward a target displayed at 5°, 10°, or 15° left or right of the central fixation point. In separate sessions, reactive and voluntary saccades were elicited by Gap-200, Gap-0, Overlap-600, and Antisaccade procedures. RESULTS Left-right asymmetries were not found in saccade latencies but appeared in saccade gain and peak velocity. Regardless of the dominant hand, saccades directed to the ipsilateral side relative to the dominant eye had larger amplitudes and faster peak velocities. CONCLUSIONS Left-right asymmetries can be explained by naso-temporal differences for some subjects and by eye dominance for others. Further investigations are needed to examine saccadic parameters more systematically in relation to eye dominance. Indeed, any method that allows one to determine ocular dominance from objective measures based on saccade parameters should greatly benefit clinical applications, such as monovision surgery.


Investigative Ophthalmology & Visual Science | 2011

Adaptation of Reactive Saccades in Normal Children

Karine Doré-Mazars; Dorine Vergilino-Perez; Christelle Lemoine; Maria Pia Bucci

PURPOSE To compare the amount, the retention, and the extinction of saccadic adaptation in two groups: 9 adults (23-36 years old) and 9 children (11-14 years old). METHODS The paradigm used was a classical double-step target to elicit the shortening of saccade gains in response to a 2° backward step (20% of target eccentricity). Two conditions were run in the pre- and postadaptation phases without and with postsaccadic visual feedback, to allow examination of the retention and the extinction of saccadic adaptation. RESULTS Adaptation of reactive saccades occurred in children as well as adults. Both groups showed a progressive shortening of saccade amplitude and good retention. The main difference concerned the speed of extinction, i.e., return to baseline, which was slower for children. CONCLUSIONS Cerebral structures involved in human short-term adaptation of reactive saccades are functional in regard to adaptive shortening of saccade amplitude. Divergent patterns in the extinction of adaptation between children and adults suggested that lengthening of saccade gain is not yet well established in children. Further investigation is needed to clarify whether processes responsible for backward adaptation are mature before those for forward adaptation.


PLOS ONE | 2014

Perceptual and Gaze Biases during Face Processing: Related or Not?

Hélène Samson; Nicole Fiori-Duharcourt; Karine Doré-Mazars; Christelle Lemoine; Dorine Vergilino-Perez

Previous studies have demonstrated a left perceptual bias while looking at faces, due to the fact that observers mainly use information from the left side of a face (from the observers point of view) to perform a judgment task. Such a bias is consistent with the right hemisphere dominance for face processing and has sometimes been linked to a left gaze bias, i.e. more and/or longer fixations on the left side of the face. Here, we recorded eye-movements, in two different experiments during a gender judgment task, using normal and chimeric faces which were presented above, below, right or left to the central fixation point or on it (central position). Participants performed the judgment task by remaining fixated on the fixation point or after executing several saccades (up to three). A left perceptual bias was not systematically found as it depended on the number of allowed saccades and face position. Moreover, the gaze bias clearly depended on the face position as the initial fixation was guided by face position and landed on the closest half-face, toward the center of gravity of the face. The analysis of the subsequent fixations revealed that observers move their eyes from one side to the other. More importantly, no apparent link between gaze and perceptual biases was found here. This implies that we do not look necessarily toward the side of the face that we use to make a gender judgment task. Despite the fact that these results may be limited by the absence of perceptual and gaze biases in some conditions, we emphasized the inter-individual differences observed in terms of perceptual bias, hinting at the importance of performing individual analysis and drawing attention to the influence of the method used to study this bias.


Journal Francais D Ophtalmologie | 2015

Vers une quantification de la dominance oculaire pour une meilleure prise en charge des pathologies de l’œil☆

Romain Chaumillon; Nadia Alahyane; Patrice Senot; Judith Vergne; Christelle Lemoine; Karine Doré-Mazars; Jean Blouin; Dorine Vergilino-Perez; Alain Guillaume

INTRODUCTION The dominant eye is defined as the one we unconsciously choose when we have to perform monocular tasks. In the field of clinical neuro-ophthalmology, it is well-established that ocular dominance plays a key role in several eye diseases. Furthermore, the accurate quantification of ocular dominance is crucial with regard to certain surgical techniques. However, classical preoperative tests cannot determine the amount of ocular dominance. MATERIALS AND METHODS In order to obtain further insight into the phenomenon of ocular dominance, we study its influence at behavioral and neurophysiological levels (experiments 1 and 2). Based on these new data, we suggest a method to improve quantification of ocular dominance (experiment 3). RESULTS We demonstrate that ocular dominance has an influence on hand movements and on interhemispheric transfer time. Moreover, we show that an analysis of the dynamics of saccades allows us to sort out participants with strong or weak ocular dominance. CONCLUSION In conclusion, this better understanding of the phenomenon of ocular dominance, coupled with the analysis of saccadic dynamics, might, in the short or medium term, lead to the establishment of a quick and straightforward battery of tests allowing determination of the amount of ocular dominance for each patient.


Neuropsychologia | 2012

The Role of Saccade Preparation in Lateralized Word Recognition: Evidence for the Attentional Bias Theory.

Dorine Vergilino Perez; Christelle Lemoine; Eric Siéroff; Anne-Marie Ergis; Redha Bouhired; Emilie Rigault; Karine Doré-Mazars

Words presented to the right visual field (RVF) are recognized more readily than those presented to the left visual field (LVF). Whereas the attentional bias theory proposes an explanation in terms of attentional imbalance between visual fields, the attentional advantage theory assumes that words presented to the RVF are processed automatically while LVF words need attention. In this study, we exploited coupling between attention and saccadic eye movements to orient spatial attention to one or the other visual field. The first experiment compared conditions wherein participants had to remain fixated centrally or had to make a saccade to the visual field in which subsequent verbal stimuli were displayed. The orienting of attention by saccade preparation improved performance in a lexical decision task in both the LVF and the RVF. In the second experiment, participants had to make a saccade either to the visual field where verbal stimuli were presented subsequently or to the opposite side. For RVF as well as for LVF presentation, saccade preparation toward the opposite side decreased performance compared to the same side condition. These results are better explained by the attentional bias theory, and are discussed in the light of a new attentional theory dissociating two major components of attention, namely preparation and selection.


Brain Research | 2011

Exploring and targeting saccades dissociated by saccadic adaptation

Louisa Lavergne; Dorine Vergilino-Perez; Christelle Lemoine; Thérèse Collins; Karine Doré-Mazars

Saccadic adaptation maintains saccade accuracy and has been studied with targeting saccades, i.e. saccades that bring the gaze to a target, with the classical intra-saccadic step procedure in which the target systematically jumps to a new position during saccade execution. Post-saccadic visual feedback about the error between target position and the saccade landing position is crucial to establish and maintain adaptation. However, recent research focusing on two-saccade sequences has shown that exploring saccades, i.e. saccades that explore an object, resists this classical intra-saccadic step procedure but can be adapted by systematically changing the main parameter used for their coding: stimulus size. Here, we adapted an exploring saccade and a targeting saccade in two separate experiments, using the appropriate adaptation procedure, and we tested whether the adaptation induced on one saccade type transferred to the other. We showed that whereas classical targeting saccade adaptation does not transfer to exploring saccades, the reciprocal transfer (i.e., from exploring to targeting saccades) occurred when targeting saccades aimed for a spatially extended stimulus, but not when they aimed for an isolated target. These results show that, in addition to position errors, size errors can drive adaptation, and confirm that exploring vs. targeting a stimulus leads to two different motor planning modes.


Experimental Brain Research | 2013

Differing effects of prosaccades and antisaccades on postural stability

Agathe Legrand; Karine Doré Mazars; Julie Lazzareschi; Christelle Lemoine; Isabelle Olivier; J. Barra; Maria Pia Bucci


Experimental Brain Research | 2014

Characteristics of contralesional and ipsilesional saccades in hemianopic patients

Alexandra Fayel; Sylvie Chokron; Céline Cavézian; Dorine Vergilino-Perez; Christelle Lemoine; Karine Doré-Mazars


Developmental Psychobiology | 2008

Development of inter‐manual transfer of shape information in infancy

Arlette Streri; Christelle Lemoine; Emmanuel Devouche

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Agathe Legrand

Paris Descartes University

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Maria Pia Bucci

Paris Descartes University

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Isabelle Olivier

Centre national de la recherche scientifique

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Alexandra Fayel

Paris Descartes University

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Anne-Marie Ergis

Paris Descartes University

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Arlette Streri

Paris Descartes University

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Dorine Vergilino Perez

Institut Universitaire de France

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