Focusing on control and learning in the human oculomotor system, my work aims at showing that eye movement consequences can play a fundamental – reinforcing – role in the modification of saccadic properties.
First, in the series of experiments I conducted during my undergraduate and graduate studies in Lille 3 under Prof. L. Madelain’s supervision, we eliminated retinal error and provided auditory consequences after saccades met specific criteria of gain median or variability. The increases and decreases induced in gain levels were similar to adaptations obtained via a double-step paradigm, and our reinforcement procedures modified saccadic gain variability independently of the median. These results show that a general operant learning process can guide changes in saccadic gain distributions. These studies focused on single horizontal saccades.
Then I studied saccades generated during visual search. We designed a new research paradigm involving a visual search task where finding a target among distractors was effective at reinforcing various levels of saccadic amplitude variability. I extended this work during a first postdoctoral fellowship with Prof. K. Gegenfurtner and Dr. A. Schütz by assessing the influence of learned contingencies between specific saccadic responses and their visual consequences during a visual search task in a noisy background. Taken together, these findings indicate that in real life, seeing the target appears to be a visual consequence determining visual search strategies.
In the CAVlab, I am currently investigating how learning influences the perception of the predicted saccadic consequences. After saccade targets had changed during the eye movement, what did we (learn to) see?
I received my PhD in Neuroscience at University of Tsukuba in Japan. I am visiting Patrick Cavanagh at the Centre Attention & Vision in January and February 2012. My interesting is cognitive process affected by own movement. In particular, I would like to have suggestion about interaction between visual function and movement plan information for visual stabilization.
I am interested in visual attention, eye movements and spatial perception. I have focused on how the brain creates a stable visual percept across eye movements and which role spatial attention plays in this process. Other interests are visual attention in visual search, attention in consciousness, cross modal perception and synaesthesia, that is, the experience of two sensory modalities where there is only one sensory input.
My research focuses on the interplay between attention, eye movements and visual perception. While I had already developed a liking for cognitive psychology and research on visual perception during my first two years of study at the Johannes Gutenberg University, Mainz, Germany, I fell in love with eye movement research while conducting my diplom (former German equivalent to MSc/MA) thesis in the lab of Boris M. Velichkovsky at Dresden University of Technology, Germany. In my PhD project at Dirk Kerzel's lab at the University of Geneva, Switzerland, I investigated the influence of visual distractors on eye movement latencies: What can make us hesitate to change our line of sight? Which visual events can capture our gaze? How can this be modulated by intentions or expections? Part of this research was also conducted during my three-month research stay in the lab of Jan Theeuwes, Vrije Universiteit Amsterdam, NL. After my PhD, I continued my work with Dirk Kerzel in Geneva as a postdoc, this time focussing more on the role of attention while performing eye movements: Does the attentional and the oculomotor system share the same resources? Is there a mandatory coupling between target selection for eye movements and attention? If so, are there attentional consequences that are unaffected by eye movements? These studies were conducted in close collaboration with Ulrich Ansorge, University of Vienna, Austria. Further, I had the opportunity to visit Jay Pratt's lab in Toronto, Canada for two months, examining feature-based attentional effects on temporal order judgements (coming soon...). I also became interested in questions of visual stability: how do we perceive our world as stable despite continuously changing visual input due to (eye) movements. From there, it was only natural to apply for a job at the CAVlab where I am involved in research centering exactly aroung this question. For instance, in one of my current projects in collaboration with Eckart Zimmermann, Forschungszentrum Julich, Germany, we try to disentangle which perceptual phenomena may be signature effects of compensatory mechanisms for eye movements (remapping) and which may not.
After a Master in Philosopy centered on the interaction between action and perception in Bergson (University of Tours, France, 2008) and a Master in Cognitive Sciences (ENS, EHESS, Paris Descartes, Paris, France, 2011), I joined the CavLab as a PhD student to focus my work on the understanding of how a long-training in drawing can affect and perhaps modify the visual system organization and its processing. Typically, why are some people better at drawing than others? What does the visual system must learn for allowing an accurate drawing? What and how visual information must be processed and integrated in sight of the motor production?
I completed my PhD in psychology at the University of Padua, under the supervision of Marco Zorzi, focusing on visual attention with an approach that combined behavioral experiments and computational modeling. I was interested into how visual attention works under different conditions, for example during the execution of eye movements, in conditions where multiple targets has to be attended at the same time, or after brain damage. My interests led me in 2012 to a first visit at the CAVlab, where I further investigated the interaction between attention and eye movements. I am now glad to be back in Paris as a postdoc, working with Patrick Cavanagh in a project that aims to find out how the brain code location, i.e. how it assign a perceived object to a specific location, and what is the role of attention and eye movement systems in this process
My interest in visual perception was sparked as an undergraduate at the Australian National University, where I also completed my PhD with Mark Edwards (2004-2007). My work in this time focussed on the integrative processes required to perceive multiple directions of motion simultaneously. These interests in low-level vision developed during a postdoctoral fellowship at University College London with Steven Dakin and Peter Bex (2008-2010). In this time I focussed on peripheral vision and crowding, the deleterious effect of ‘clutter’ on object recognition, in both the ‘normal’ visual system and in children with amblyopia. Along the way I have also examined our perception of depth, position, and numerosity, as well as change-detection and attention. I am endlessly fascinated by the many tasks accomplished by the brain, and hope to uncover more of its secrets as I examine issues in spatial vision and crowding with Patrick Cavanagh and the CAVlab.
My interest in vision research arose while studying psychology in Strasbourg where I first realized what an amazing task our visual system does: It takes the ambiguous and incomplete information that is “captured” by the retina and generates a coherent representation of the world. Doing my Ph.D. in Tübingen, I investigated how attention can influence this process. As a post-doc in Iowa City I pursued the question of how the visual system organizes the visual information that is sampled from constantly changing input into meaningful units and how those units are updated over time, looking at apparent motion and masking. Here in Paris I am continuing this quest by asking in particular what consequences the updating process has for the content of the organized representations.
After a Master in Psychology and Computer Science (CAU, Kiel), I received my PhD in Neuroscience at the École Polytechnique Fédérale de Lausanne (EPFL). In June 2010, I started my postdoc with Patrick Cavanagh here at the Centre Attention & Vision. I am interested in the mechanisms that generate a rich and stable perception of the world from the highly ambiguous and ever-changing light pattern falling on the retina. In particular, I am intrigued by the complex interactions between local and global levels of stimulus processing and their dependence on factors such as grouping, figure-ground segregation, and Gestalt.
PhD of Neurosciences from Ludwig-Maximilians University of Munich, Germany. In every day situations we move our eyes and hands countless number of times. Yet, even though those tasks seem effortless, a number of computations in our visual and motor systems have to be completed before we can start any movement. One aspect of preparation for action I find particularly interesting - it has been observed, that eye and hand movement plans affect the way we perceive our surrounding world. Thus, we are suddenly better to observe events happening at saccade or reach movement goal locations even before movement starts, we get really bad to see objects appearing at locations to which actions are forbidden, and our visual system prepares for changes in visual input across eye movements. All these aspects of visual processing related to action planning are extremely interesting to me, as they illustrate that our visual system does not just passively collect information, but visual information processing is in large part affected by our intentions to deal with a world surrounding us. Here in Paris I am excited to further investigate visual processing before and after eye movements and to further uncover how our action and visual systems interact.
In March 2008, I started a postdoc in the new lab of Patrick Cavanagh. The topic that we both share a passion for is visual direction constancy, or, spatiotopy. That is, why seems visual perception so remarkably continuous in space and time despite the fact that eye-, head-, and body-movements produce large-scale transitions in the input stream on the retina? And how do we keep track of things are around us if they jump around on our receptors? Neurophysiology has provided a number of findings that may guide our way. Together with Tomas Knapen, my office-mate who is also postdoc in our lab, we are probing in various ways how visual direction constancy may be achieved. I am confident that we will come up with insightful data to finally arrive at a model of transsacadic perception that is able to account for all these mysteries. I also started a collaboration with Thérèse Collins at the University of Hamburg on some interesting aspects of these issues.
I am intrigued by the fact that our brains seem to create the world we live in so effortlessly all day long, for our entire lives. We have for ourselves the impression of a very coherent mental image that we sample almost objectively from the outside world, don't we? Actually what our brain does when we 'look' is a very interpretative process based on extremely noisy information, implemented in extremely noisy hardware. It is no wonder, then, that the stability and reliability that we perceive and depend on is an illusion.
I finished my Ph.D. in experimental psychology in 2008 at Université de Montréal with Jocelyn Faubert as an advisor. Since then, I am pursuing a postdoc with Patrick Cavanagh at Université de Paris-Descartes. My main research interests are the processing of first- and second-order motion and signal detection in noise.
In 2012 PhD
I finished a Master in Cognitive Science (ENS, EHESS, Paris Descartes University) in June 2009 and started my phD in the "Cav lab" with Patrick Cavanagh since september 2009. I am generally interested in understanding the mechanisms underlying visual perception and attention.
In 2012 Masters 1
In 2010 Masters 1
In 2009 Masters 2
Floris van Vugt
I am interested in response conflict, such as the Stroop task, as measured by pointing trajectories. Imagine you name the ink colour of a word. That's much harder if the word itself is the name of a different colour (e.g. GREEN, written in red). In my tasks, the subject responds by pointing to the correct one among a bunch of colours. I like to investigate how we can see the conflict in the path of the pointing movement, because this gives us a map over time of what happens inside the subject's head. Using these tools, I hope to gain an understanding of spatial language: the language that we use to talk about what we see.
I am currently an undergraduate at Harvard University, where I study cognitive neuroscience and psychology. Before Harvard, I lived in Johnson, Vermont, Bailly, France, and most recently New York City, which I call home. My childhood experience in France sparked my lifelong need to return here as much as possible, bringing me to the LPP, where I am an intern in the visual attention center. I have also cherished a passion for dance since the age of three, and I hope to succeed in linking my academic and artistic interests in an intimate and complementary way that allows me to avoid abandoning either one. I look forward to doing research on the phenomenon of muscle memory which I observe in dance as the transition from conscious motor processes to seemingly autonomic signals drawn from memory after frequent repetition. Of course, at 19 years old, all this is yet to come for me!
Thi Bich Doan