Laurent Madelain

• PhD
• Professor (Full) at University of Lille

Both the gap and overlap paradigm may reveal the interaction between fixating and moving the eyes, but the effects of the overlap paradigm have not been fully characterized yet. Here we present a series of experiments probing how an overlap paradigm, combined with the manipulation of stimuli durations, saliency and transient changes might modulate...

Abstract That saccadic reaction times (SRTs) may depend on reinforcement contingencies has been repeatedly demonstrated. It follows that one must be able to discriminate one’s latencies to adequately assign credit to one’s actions, which is to connect behaviour to its consequence. To quantify the ability to perceive one’s SRT, we used an adaptive p...

The Contingency-Discriminability model of choice has generally used a constant (p or m) to describe confusion between response location and reinforcers when location is unchanging, and the same approach has usually been taken in the development in models that combine control of elapsed time and reinforcer location. The value of m is the probability...

Saccadic eye movements bring events of interest to the center of the retina, enabling detailed visual analysis. This study explored whether irrelevant auditory (experiments A, B & F), visual (C & D) or tactile signals (E & F) delivered around the onset of a visual target modulates saccade latency. Participants were instructed to execute a quick sac...

Many daily life situations (e.g. dodging an approaching object or hitting a moving target) require people to correct planning of future movements based on previous temporal errors. However, the actual temporal error can be difficult to perceive: imagine a baseball batter that swings and misses a fastball. Here we show that in such situations people...

Saccadic eye movements bring events of interest to the center of the retina, enabling detailed visual analysis. This study explored whether irrelevant auditory (experiments A, B & F), visual (C & D) or tactile signals (E & F) delivered around the onset of a visual target modulates saccade latency. Participants were instructed to execute a quick sac...

Saccadic latencies are known to change as a function of target eccentricity and size. Recently, it has been shown that latencies consistently change according to the amplitude of the step in proportion to the size of the target (Madelain, Krauzlis, & Wallman, 2005; Harwood, Madelain, Krauzlis, & Wallman, 2008; De Vries, Azadi, & Harwood, 2016). Thi...

Recent studies have demonstrated that saccadic reaction times (SRTs) are influenced by the temporal regularities of dynamic environments (Vullings & Madelain, 2018). Here, we ask whether discriminative control (i.e., the possibility to use external stimuli signaling the future state of the environment) of latencies in a search task might be establi...

When predictive information about target motion is available, anticipatory smooth pursuit eye movements (aSPEM) are consistently generated before target appearance, thereby reducing the typical sensorimotor delay between target motion onset and foveation. By manipulating the probability for target motion direction, we were able to bias the directio...

Correction on the basis of previous errors is paramount to sensorimotor learning. While corrections of spatial errors have been studied extensively, little is known about corrections of previous temporal errors. We tackled this problem in different conditions involving arm movements (AM), saccadic eye movements (SM) or button presses (BP). The task...

Both the gap and overlap paradigm may reveal the interaction between fixating and moving the eyes, but the effects of the overlap paradigm have not been fully characterized yet. Here we present a series of experiments probing how an overlap paradigm, combined with the manipulation of stimuli durations, saliency and transient changes might modulate...

Previous studies showed that a temporal overlapping of the fixation-target with the saccade-target onset induces a shift of saccade reaction time distributions towards longer values. Here we present a series of experiments probing how an overlap paradigm, combined with the manipulation of stimuli durations, energy and transient changes might modula...

-

Saccadic adaptation reflects the oculomotor system ability to adapt in response to changes in sensorimotor contingencies. Reinforcement learning can induce saccade adaptation in the absence of a visual position error suggesting that conventional saccade adaptation might involve general learning mechanisms rather than only specific motor calibration...

Conventional decision models view reaction time as a consequence of the duration of decision-making process. However, some studies have shown that reaction time distributions may be strongly affected by reinforcement contingencies (Madelain et al., 2007). Here, we probe the possibility to voluntarily control saccadic latencies in a choice paradigm....

Previous studies have shown that smooth pursuit can be modulated by reward either during transient target blanking (Madelain and Krauzlis, 2003), or during pursuit of an ambiguous stimulus (Schütz et al, 2015). Moreover, anticipatory smooth pursuit eye movements (aSPEM) are observed before target appearance when predictive information about target...

Saccade adaptation is a form of motor learning that maintains saccade accuracy when facing new sensorimotor contingencies. Researchers have shown that distinct saccade gain states can be adapted simultaneously in a double-step paradigm depending on contexts acting on the motor command (e.g. velocity or direction of target motion, head tilt, orbital...

Saccade adaptation is a form of motor learning that maintains saccade accuracy when facing new sensorimotor contingencies. Researchers have shown that distinct saccade gain states can be adapted simultaneously in a double-step paradigm depending on contexts acting on the motor command (e.g. velocity or direction of target motion, head tilt, orbital...

Previous work has shown that the ability to track with the eye a moving target is substantially improved when the target is self-moved by the subject's hand in comparison to when being externally-moved. Here we explored a situation in which the mapping between hand movement and target motion was perturbed by simulating an elastic relationship betwe...

-

A recent series of experiments has shown that the effects of near-threshold stimuli on perceptual and motor responses are highly dependent on experimental conditions. In particular, motor influences of near-threshold distractors were observed when using low contrast unmasked stimuli and high contrast masked stimuli although only the latter affected...

When an object is moving in the visual field, we are able to accurately track it with a combination of saccades and smooth eye movements. These movements allow us to align and stabilize the object on the fovea, thus enabling visual analysis with high acuity. Importantly, when predictive information is available about the target motion, anticipatory...

-

Saccade adaptation is a form of motor learning that maintains saccade accuracy in response to new sensorimotor contingencies. Several studies have shown that saccade gain can be adapted separately in double-step paradigms depending on cues affecting the motor command (velocity or direction of target motion, orbital eccentricity, or vergence). Howev...

When an object is moving in the visual field, we are able to accurately track it with a combination of saccades and smooth eye movements. These movements allow us to align and stabilize the object on the fovea, thus enabling visual analysis with high acuity. Importantly, when predictive information is available about the target motion, anticipatory...

Human observers often adopt rigid scanning strategies in visual search tasks, even though this may lead to suboptimal performance. Here we ask whether specific levels of saccadic amplitude variability may be induced in a visual search task using reinforcement learning. We designed a new gaze-contingent visual foraging task in which finding a target...

Studies of decision-making process revealed that animals are sensitive to the sources and timing of rewards and use these variables to choose among alternatives. In particular experiments on foraging behavior indicate that the distribution of time among foraging sites is proportional to their relative value. These relations were expanded to a gener...

At slow target velocities, there is a linear increase in smooth pursuit eye velocity gain with increasing contrast, a phenomenon which supports the assumption that perceptual and motor responses are driven by a shared signal: low-contrast stimuli consistently appear slower than the same targets presented at higher contrast. The "footstep" illusion...

The observation that near threshold low contrast visual distractors can equally influence perceptual state and goal-directed motor responses was recently taken as an argument against a sharp separation between a conscious vision for perception and an unconscious vision for action. However, data supporting the dual visual system theory have principa...

The oculomotor system maintains saccade accuracy by adjusting saccades that are consistently inaccurate. Four experiments were performed to determine the relative contribution of background and target postsaccadic displacement. Unlike typical saccade adaptation experiments, we used natural image scenes and masked target and background displacements...

Purpose. When a target is surreptitiously displaced forward or backward during a saccade the saccadic amplitude progressively changes. This saccadic adaptation is often viewed as being driven by the mismatch between a predicted and an actual post-saccadic visual position error. However, we recently demonstrated that saccadic adaptation may be induc...

Purpose We recently showed that part of saccadic amplitude variability may be controlled by operant learning (Paeye & Madelain, 2011). Saccadic amplitude distributions were reinforced with a tone depending on amplitude variability criteria. In the present study we designed a new paradigm involving a visual search task to test whether finding a targ...

The aim of this review is to present empirical and neurobiological evidence in favour of a coupling between spatial attention and saccadic control. Visual exploration involves complex attentional processes in charge for the inhibition of non-relevant parts of the visual field in order to select areas of interest. An overview of the literature empha...

The aim of this review is to present empirical and neurobiological evidence in favour of a coupling between spatial attention and saccadic control. Visual exploration involves complex attentional processes in charge for the inhibition of non-relevant parts of the visual field in order to select areas of interest. An overview of the literature empha...

Control of saccadic gain is often viewed as a simple compensatory process in which gain is adjusted over many trials by the postsaccadic retinal error, thereby maintaining saccadic accuracy. Here, we propose that gain might also be changed by a reinforcement process not requiring a visual error. To test this hypothesis, we used experimental paradig...

Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we rein...

Saccade and smooth pursuit are the eye movements used by primates to shift gaze. In this article we review evidence for the effects of reinforcement on several dimensions of these responses such as their latencies, velocities or amplitudes. We propose that these responses are operant behaviours controlled by their consequences on performance of vis...

Purpose: During smooth pursuit of a compound stimulus (2 concentric rings, one 0.8 deg, the other 8 deg), the latency of saccades to a 1.5 deg perturbation is shorter when the spatial scale of attention is narrow (directed to small ring) than when it is broad (Madelain, Krauzlis & Wallman, Society for Neuroscience, 2001). A possible explanation for...

Providing evidence against a dissociation between conscious vision for perception and unconscious vision for action, recent studies have suggested that perceptual and motor decisions are based on a unique signal but distinct decisional thresholds. The aim of the present study was to provide a direct test of this assumption in a perceptual-motor dua...

Saccade adaptation has been extensively studied using a paradigm in which a target is displaced during the saccade, inducing an adjustment in saccade amplitude or direction. These changes in saccade amplitude are widely considered to be controlled by the post-saccadic position of the target relative to the fovea. However, because such experiments g...

It is widely held that the targets of saccades (and perhaps of attention as well) are typically selected by a winner-take-all mechanism in which maximal neural activity on some brain map (perhaps in the superior colliculus or frontal eye field) converges on one location, inhibiting other locations. If circumstances permitted the brain regions in ea...

The predominant view of saccade adaptation is that it is largely guided by retinal error–the postsaccadic distance of the target from the fovea. In laboratory experiments with the target as the only visible stimulus, the retinal error is unambiguous, unlike real life, in which any of a multitude of stimuli might be on or near the fovea after any sa...

PURPOSE. Studies of reaction time distributions provide a useful quantitative approach to understand decision processes at the neural level and at the behavioral level. A strong relationship between the spread of latencies and the median is generally accepted even though there has been no attempt to disentangle experimentally these two parameters....

Does saccadic gain adaptation, often described as a simple form of learning, have much in common with other forms of learning, in particular those guided by reinforcement? We investigated whether saccade adaptation could be guided by reinforcement if no retinal error existed. To eliminate retinal error, we either had the target vanish when the sacc...

Purpose: We previously showed that, when viewing two concentric rings (0.8 and 8 deg diameter) that together undergo a step displacement (< 8 deg), subjects make saccades at shorter latencies if they attend to the inner ring. We proposed that saccades are triggered faster when the target object leaves the spotlight of attention. We now test three o...

We have previously shown that when a stimulus consisting of two concentric rings moves, saccade latencies are much longer (by 150 ms) when attention is directed to the larger ring than to the smaller ring. Here, we investigated whether this effect can be explained by a deferral of the "cost" of making a saccade while the target remains inside the a...

Studies of reaction-time distributions provide a useful quantitative approach to understand decision processes at the neural level and at the behavioral level. A strong relationship between the spread of latencies and the median is generally accepted even though there has been no attempt to disentangle experimentally these two parameters. Here we t...

We examined the effects of changing spatial aspects of attention during oculomotor tracking. Human subjects were instructed to make a discrimination on either the small (0.8 degrees ) central or the large (8 degrees ) peripheral part of a compound stimulus (two counter-rotating concentric rings) while the stimulus either translated across the scree...

Previous research has demonstrated learning in the pursuit system, but it is unclear whether these effects are the result of changes in visual or motor processing. The ability to maintain smooth pursuit during the transient disappearance of a visual target provides a way to assess pursuit properties in the absence of visual inputs. To study the lon...

Pursuit can be guided by perceived rather than physical motion, but the temporal relationship between motion perception and pursuit is unknown. We used an apparent motion stimulus consisting of a horizontal row of evenly spaced Kanizsa illusory squares (1.44 deg2): the illusory contours appeared at the midpoints of the illusory squares presented in...

Smooth pursuit is a complex behaviour which is not considered as totally functional at birth. The lack of maturation of the visuo-motor systems is generally invoked to explain this phenomenon. However, if this oculomotor response is an operant behaviour, an alternate explanation may be found in the absence of previous confrontation with the environ...