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Institut de Neurosciences Cognitives de la Méditerranée, unité mixte de recherche de l'Université Aix Marseille II et du Centre National de Recherche Scientifique partenaire de l'Institut Fédératif de Recherche en sciences du cerveau et de la cognition
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Eric Castet


CNRS & Université de la Méditerranée
31 chemin J. Aiguier
13402 Marseille Cedex 20
Phone: 33 (0) 4 91 16 43 34.
Fax: 33 (0) 4 91 16 44 98.
Email: Eric.Castet at incm.cnrs-mrs.fr


NEW !  Grant for a Ph. D. project funded by Essilor International : Use of Gaze-contingent Augmented Vision for low vision reading !

Research interests

    Using visual psychophysics, both as a methodology and as a theoretical framework, my general interest concerns active vision. More precisely, since 1999, I have been investigating  the visual processes which take place in the temporal vicinity of  the execution of saccadic eye movements. One key question is to disentangle the respective influences of attentional, purely visual (e.g. within the retina or the primary visual cortex, ...) and so-called extra-retinal factors.

    Since 2004-2005, I have started coordinating a new related project thanks to the effcient collaboration with several ophthalmologists, orthoptists and optometrists of the La Timone hospital. Our focus is on patients with AMD (DMLA in french) who have a macular visual scotoma. In order to see, these patients have to deploy their attention to locations outside the scotoma (hence the theoretical link with the first research axis). This project is fundamental because the processes disrupted by the scotoma are not completely understood and applied because there are many  promising ways of improving these patients' visual perception.

  1. Visual perception with saccadic eye movements 

    • Visual perception during saccades :
          We have shown that  motion can be easily perceived during saccades when the retinal stimulation is appropriate for the motion sensing system (Castet & Masson, 2000, Nat. Neurosc.).  We have further shown that temporal masking is responsible for the usual absence of intra-saccadic motion perception in daily life (Castet et al., 2002, PNAS). We have proposed, but not proved, that the intra-saccadic reduction in luminance contrast sensitivity (improperly called saccadic suppression) might be caused by retinal processes in contrast to the widely accepted extra-retinal theory (Castet et al., 2001, letter in TINS).
            Although this line or research has been at rest in the last few years, the story is far from finished for me, if only because many visual scientists have apparently not been convinced by my views and/or results.
     
    • Dynamics of pre-saccadic attentional deployment 
         We have shown that the deployment of visual attention towards a saccadic target is extremely rapid - less than 200 ms (Castet et al., 2006). Using a new Posner-like paradigm, we have further quantified the amount of attentional resources which can be deployed away from the saccadic target (Montagnini & Castet, 2007). These experiments are continued within the general context of Anna Montagnini's main interest: namely visual saliency map computation during active vision.

  2. Visual psychophysics and  ophthalmology : investigation of low vision

        The main complaint of low vision patients is their difficulty to read. Our focus is therefore on reading.  Three lines of research are followed:
    • b/ Development and test of new visual rehabilitation techniques

    • c/ Development and test of new visual aids

lunettes

        These axes of research are followed with two complementary approaches : i/ we have designed a gaze-contingent visual display paradigm which simulates macular scotomas with normally-sighted observers. This simulation paradigm is used as an exploratory tool used before performing experiments with patients;  ii/  We are developing a gaze-contingent  enhanced vision paradigm which will be used in axes b/ and c/. The french acronym for this project is : projet SOLAIRE : Système d'Optimisation de la Lecture par Asservissement de l'Image au REgard.
    This project was boosted in 2006 by Jean-Baptiste Bernard  (CNRS grant - Bourse de Doctorat pour Ingénieur- BDI) and by Anne-Catherine Scherlen (post-doc from Association Retina). Besides, a grant from the 'Fondation pour l'Avenir de la Recherche Biomédicale' allowed us to buy a sophisticated eye tracker.


Collaborations

his homepage

    Previous students

Ph. D. students:                 (from 2009 : Post-doc with Susana Chung at Berkeley)

Post-docs

2004-2009 : Anna MONTAGNINI (now CNRS researcher)

2005-2006: Anne-Catherine SCHERLEN (now project manager at Essilor International)

    Current students

Ph.D. Students

Publications

1) Lorenceau J., Shiffrar M., Wells N. & Castet E. (1993). Different motion sensitive units are involved in recovering the direction of moving lines. Vision Research, 33, 1207-1217.

2) Castet E., Lorenceau J. & Bonnet C. (1993). The inverse intensity effect is not lost with stimuli in apparent motion. Vision Research, 33, 1697-1708. 

3) Castet E., Lorenceau J., Shiffrar M. & Bonnet C. (1993). Perceived speed of moving lines depends on orientation, length, speed and luminance. Vision Research, 33, 1921-1936. pdf

4) Castet E. (1994). Effect of the ISI on the visible persistence of stimuli in apparent motion. Vision Research, 34, 2103-2114.

5) Castet E. (1995). Apparent speed of sampled motion. Vision Research, 35, 1375-1384.

6) Morgan M. J. & Castet E. (1995). Stereoscopic depth perception at high velocities. Nature, 378, 380-383.

7) Castet E. & Morgan, M. J. (1996). Apparent speed of type I symmetrical plaids. Vision Research, 36, 223-232.

8) Castet E. & Wuerger, S. (1997). Perception of moving lines: interactions between local perpendicular signals and 2D motion signals.  Vision Research, 37, 705-720.

9) Morgan, M. J. & Castet, E. (1997). The aperture problem in stereopsis. Vision Research, 37, 2737-2744.

10) Morgan, M. J., Ward, R. M. & Castet, E. (1998). Visual search for a tilted target : tests of spatial uncertainty models. Quarterly Journal of Experimental Psychology, 51A, 347-370.

11) Castet, E., Charton V. & Dufour A. (1999). The extrinsic/intrinsic classification of 2D motion signals in the barberpole illusion. Vision Research, 39, 915-932.

12) Castet, E. & Zanker, J. (1999). Long-range interactions in the spatial integration of motion signals. Spatial Vision, 12, 287-307.

13) Castet, E. & Masson, G. S. (2000). Motion perception during saccadic eye movements. Nature Neuroscience, 3, 177-183.  pdf

14) Masson, G. S., Rybarczyk, Y., Castet, E. & Mestre, D. (2000). Temporal dynamics of motion integration for the initiation of tracking eye movements at ultra-short latencies. Visual Neuroscience, 17, 753-767.

15) Castet, E., Jeanjean, S. & Masson, G.S. (2001). 'Saccadic suppression' : no need for an active extra-retinal mechanism. Trends in Neurosciences, 24, 317-318.  pdf

16) Morgan, M. J. & Castet, E. (2002). High temporal frequency synchrony is insufficient for perceptual grouping. Proceedings of the Royal Society of London B, 269, 513-516.

17) Masson, G. S. & Castet, E. (2002). Parallel motion processing for the initiation of short-latency ocular following in humans. Journal of Neuroscience, 22, 5149-63.

18) Castet, E., Keeble, D.T. & Verstraten, F.A.J. (2002). Nulling the motion aftereffect with dynamic random-dot stimuli : limitations and implications. Journal of Vision, 2(4), 302-311, http://journalofvision.org/2/4/3/

19) Castet, E., Jeanjean, S. & Masson, S.J. (2002). Motion perception of saccade-induced retinal translation. Proceedings of the National Academy of Sciences USA, 99, 15159-63.

20) Castet, E., Jeanjean, S., Montagnini, A., Laugier, D., & Masson, G. S. (2006). Dynamics of attentional deployment during saccadic programming. Journal of Vision, 6(3), 196-212, http://journalofvision.org/6/3/2/

21) Montagnini, A., Mamassian, P., Perrinet, L., Castet, E., Masson, G.S., Bayesian modelling of dynamic motion integration (2007). Journal of Physiology – Paris. 101/1-3, 64-77.

22) Montagnini, A., & Castet, E. (2007). Spatiotemporal dynamics of visual attention during saccade preparation: Independence and coupling between attention and movement planning. Journal of Vision, 7(14):8, 1-16, http://journalofvision.org/7/14/8/

23) L. Hoffart, J. Conrath, F. Matonti, F. Galland, N. Wotawa, F. Chavane, E. Castet, B. Ridings, G. S. Masson. (2007). Étude en IRM fonctionnelle 3T de l’organisation rétinotopique du cortex visuel J Fr. Ophtalmol., 30, 8, 830-836.

24) Bernard, J-B, Scherlen A-C & Castet E. (2007). Page mode reading with simulated scotomas: A modest effect of interline spacing on reading speed. Vision Research., 47 (28), 3447-3459.

25) Barthelemy, F.V., Perrinet, L.U., Castet, E., & Masson, G.S. (2008). Dynamics of distributed 1D and 2D motion representations for short-latency ocular following. Vision Res, 48 (4), 501-522.

26) Scherlen A-C., Bernard, J-B, Calabrèse, A. & Castet E. (sous presse). Page mode reading with simulated scotomas : oculo-motor patterns. Vision Research

 

 

Conferences

1) Gorea A. & Castet E. (1991). The uniqueness of perceived speed of multi-attribute moving stimuli. Investigative Ophthalmology & Visual Science ARVO Supplement, 32, 828.

 2) Gorea A., Agonie C. & Castet E. (1991). Luminance- and color-carried motion interactions as revealed by independent equivalent-luminance-contrast assessments. Perception ECVP Supplement , 20, 96.

3) Lorenceau J., Castet E. & Shiffrar M. (1992). Find the odd one out. Perception ECVP Supplement , 21, 48.

4) Castet E., Lorenceau J. & Bonnet C. (1992). Visible persistence of moving stimuli depends on luminance. Perception ECVP Supplement , 21, 43.

5) Castet E., Lorenceau J., Shiffrar M. & Bonnet C. (1993). Misperceived speed of oblique straight lines  in translation. Perception ECVP Supplement, 22, 27.

6) Castet E. & Morgan M. (1994). Does perceived speed of translating plaids depend only on second-order motion signals? Perception ECVP Supplement, 23, 65.

7) Morgan, M. J. & Castet, E. (1995). Stereoacuity for oblique gratings predicted by phase shifts, not disparities. Investigative Ophthalmology & Visual Science ARVO Supplement, 36, 231.

8) Castet, E. & Wuerger, S. (1995). Moving lines: integration of 2D and 1D motion signals. Perception ECVP Supplement, 24, 111.

9) Castet E., Dufour A. & Bonnet C. (1996). Disambiguation of 1D motion signals in the barber pole. Investigative Ophthalmology & Visual Science ARVO Supplement, 37, 737.

10) Dufour A. & Castet, E. (1997). The misperception of the direction of a feature added on a moving line is eliminated with static cues. Perception ECVP Supplement, 26, 120.

11) Castet, E., Charton V. & Dufour A. (1997). The extrinsic/intrinsic classification of motion signals is a high-level process. Perception ECVP Supplement, 26, 87.

12) Castet, E. & Charton, V. (1998). Partial occlusion, more than binocular disparity, renders 2D motion signals extrinsic. Investigative Ophthalmology & Visual Science ARVO Supplement, 39, 847.

13) Castet, E. & Zanker, J. (1998). Long-range interactions in the integration of 2D and 1D motion signals. Perception ECVP Supplement, 27, 186.

14) Castet, E. & Masson, G.S. (1999). Motion perception is not switched off during saccades. Perception ECVP Supplement, 28, 25.

15) Masson, G., Rybarczyk, Y., Castet, E. & Mestre, D. (1999). Motion integration for tracking eye movements : the fast and the slow of it. Perception ECVP Supplement, 28, 80.

16) Masson, G.S., Rybarczyk, Y., Castet, E. & Mestre, D. (1999). 1D and 2D motion signals integration for the initiation of short-latency ocular following in humans.  Society for Neuroscience Abstracts, 25, 221.7.

17) Masson, G.S., Castet, E. & Mestre, D.R. (2000). Short-latency ocular following responses to moving plaids in humans : temporal dynamics and spatio-temporal tuning. Perception ECVP Supplement, 29, 84.

18) Castet, E. & Masson, G.S. (2000). Spatial characteristics of intra-saccadic perception. Perception ECVP Supplement, 29, 35.

19) Castet, E., Jeanjean, S. & Masson, G.S.  (2001). Intrasaccadic motion perception of a static grating. Investigative Ophthalmology & Visual Science ARVO Supplement, 42, 531.

20) Masson, G.S. & Castet, E. (2001). Short-latency ocular following responses to moving plaids in humans : temporal dynamics and spatio-temporal tuning. Soc. Neurosc., 26, 784 - 14.

21)Gepner, B., Rondan, C., Castet, E., Deruelle, C., Masson, G., Tardif, C., & Mestre, D., (2002). Optokinetic nystagmus is markedly impaired in children with autism : another argument for a visual motion processing deficit. 15th International Congress of the International Association of Child and Adolescent Psychiatry and Allied Professions (IACAPAP), New Delhi, India.

22) Castet, E., Jeanjean, S., Masson, G.S., (2002). Optimal retinal stimulation for intrasaccadic motion perception of a static grating, Perception ECVP Supplement, 31, 9.

23) Rondan C., Castet E., Deruelle C., Gepner B., Masson G. & Mestre D. (2003). Nystagmus optocinétique et intégration des signaux de mouvement chez l’enfant autiste. Résumé présenté au Congrés Autisme, Cerveau et Développement: de la Recherche à la Pratique. Collège de France, Paris, 23-24 Juin.

24) Wotawa, N., Thirion, B., Castet, E., Anton, J.L. & Faugeras, O. (2003). Efficient Human Retinotopic Mapping Using fMRI. NeuroImage (Human Brain Mapping 03).

25) Jeanjean, S., Masson, G.S. & Castet, E. (2003). Time course of intrasaccadic reduction of contrast sensitivity : horizontal vs vertical gratings. Perception ECVP Supplement, 32, 112.

26) Barthelemy, F., Castet, E. & Masson, G.S. (2003). Contrast response function and spatial summation of human short-latency ocular following. Perception ECVP Supplement, 32, 110.

27) Perrinet, L., Castet, E. & Masson, G.S. (2004). A dynamic model for the visual perception of motion using parallel, lateral, and inferential interactions. Perception ECVP Supplement, 33, 70.

28) Jeanjean, S., Masson, G.S & Castet, E. (2004). Intrasaccadic perception of gratings with low and high spatial frequency. Perception ECVP Supplement, 33, 146.

29) Castet, E., Jeanjean, S., Masson, G.S. & Laugier, D. (2004). Temporal course of pre-saccadic allocation of attention. Perception ECVP Supplement, 33, 16.

30) Hoffart, L., N. Wotawa, N., Castet, E., Chavane, F., Conrath, J, Ridings, G, & Masson, G.S. (2005). Effect of visual scotomas on the retinotopic organization of the human visual cortex: a quantitative fMRI study. Investigative Ophthalmology & Visual Science ARVO Supplement.

31) Montagnini, A., Filali-Sadouk, N., Masson, G.S & Castet, E. (2005).  Spatio-temporal characterization of presaccadic allocation of attention. Perception ECVP Supplement, 34, 91.

32) Perrinet, L., Barthélemy, F., Castet, E. & Masson, G.S. (2005). Dynamics of motion representation in short-latency ocular following: A two-pathways Bayesian model. Perception ECVP Supplement, 34, 38.

33) Hoffart L., Conrath J., Wotawa N., Castet E., Chavane F., Masson G., Ridings B. (2005). Etude en I.R.M. fonctionnelle de l'organisation rétinotopique du cortex visuel et de la représentation corticale de scotomes d'origine rétinienne. Congrès Annuel de la Société Française d'Ophtalmologie.

34) Masson GS, Barthélemy F, Vanzetta I & Castet E. (2006) Dynamics of motion integration for tracking eye movements. FENS Meeting. Symposium. Vienne Juillet 2006

35) Montagnini, A.& Castet, E. (2006). How much attention is needed for saccadic programming? Perception ECVP Supplement, 35, 19.

36) Montagnini, A., Mamassian, P., Perrinet, L., Castet, E., & Masson, G. (2006) Bayesian modeling of dynamic motion integration. Neurocomp, 1ère conférence française de Neurosciences Computationnelles, Pont-A-Mousson, France.

37) Montagnini A. & Castet, E. (2006). Dynamics of visual perception during saccadic programming. Third International Conference on Enactive Interfaces.  Montpellier, France. 20-21 nov 2006

38) Bernard, J-B., Scherlen, A-C, Vitu-Thibault, F & Castet, E. (2007). Effect of line spacing on reading speed in normally-sighted subjects with an artificial scotoma. Société des Neurosciences, 8eme colloque, résumé: p. 191.

39) Bernard, J.-B., Scherlen, A.-C., Vitu-Thibault, F., & Castet, E. (2007). Effect of line spacing on reading speed in normally-sighted subjects with an artificial scotoma [VSS Abstract]. Journal of Vision, 7(9):518, 518a, http://journalofvision.org/7/9/518/

40) Bernard, J-B., Scherlen, A-C & Castet, E. (2007). Vertical interline spacing is not a major limiting factor of reading speed with a central artificial scotoma. Perception ECVP Supplement, 36, 158.

41) Montagnini, A., & Castet, E. (2008). Presaccadic deployment of attention: what is the trigger? [Abstract]. /Journal of Vision/, /8/(6):109, 109a, http://journalofvision.org/8/6/109/, doi:10.1167/8.6.109.

 

Technical reports

Wotawa, N., Thirion, B., Castet, E., Anton, J.L., Faugeras, O. (2005). Human retinotopic mapping using fMRI. INRIA Research Report: 5472, January 2005. http://www.inria.fr/rrrt/rr-5472.html

Tlapale, E., Bernard, J.B, Castet, E. & Kornprobst, P. (2006). Le Projet SOLAIRE: Un Système d'Optimisation de la Lecture par Asservissement de l'Image au Regard. RT 0326 – INRIA Technical Report (19 p) - go to INRIA web site


INCM,UMR 6193 CNRS-Université de la Méditerranée 31, chemin Joseph Aiguier 13402 Marseille cedex. Tèl : 04 91 16 43 18
Directeur : Driss BOUSSAOUD E-mail : boussaoud at incm.cnrs-mrs.fr