Anna Montagnini

Anna Montagnini
French National Centre for Scientific Research | CNRS · Institut de Neurosciences de la Timone

PhD

About

76
Publications
4,256
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1,021
Citations

Publications

Publications (76)
Article
Full-text available
In fast vision, local spatial properties of the visual scene can automatically capture the observer’s attention. We used specific local features, predicted by a constrained maximum-entropy model to be optimal information-carriers, as candidate “salient features''. Previous studies showed that participants choose these optimal features as “more sali...
Article
Full-text available
Under fast viewing conditions, the visual system extracts salient and simplified representations of complex visual scenes. Saccadic eye movements optimize such visual analysis through the dynamic sampling of the most informative and salient regions in the scene. However, a general definition of saliency, as well as its role for natural active visio...
Article
Smooth pursuit eye movements and visual motion perception rely on the integration of current sensory signals with past experience. Experience shapes our expectation of current visual events and can drive eye movement responses made in anticipation of a target, such as anticipatory pursuit. Previous research revealed consistent effects of expectatio...
Preprint
Full-text available
Smooth pursuit eye movements and visual motion perception rely on the integration of current sensory signals with past experience. Experience shapes our expectation of current visual events and can drive eye movement responses made in anticipation of a target, such as anticipatory pursuit. Previous research revealed consistent effects of expectatio...
Article
Full-text available
Animal behavior constantly adapts to changes, for example when the statistical properties of the environment change unexpectedly. For an agent that interacts with this volatile setting, it is important to react accurately and as quickly as possible. It has already been shown that when a random sequence of motion ramps of a visual target is biased t...
Preprint
Full-text available
Animal behavior constantly adapts to changes, for example when the statistical properties of the environment change unexpectedly. For an agent that interacts with this volatile setting, it is important to react accurately and as quickly as possible. It has already been shown that when a random sequence of motion ramps of a visual target is biased t...
Poster
Visual decision-making is a widely explored area of research, yet several aspects of such complex phenomenon remain unclear. In the present work, we focused on a motion discrimination task and analysed spontaneous smooth eye movements (as well as pupil size), and their relationship with behavioural performance while manipulating task difficulty (i....
Article
Full-text available
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...
Poster
Full-text available
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...
Conference Paper
Full-text available
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...
Article
Full-text available
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...
Article
Illusory hand movements can be elicited by a textured disk or a visual pattern rotating under one's hand, while proprioceptive inputs convey immobility information (Blanchard et al., 2013). Here we investigated whether visuo-tactile integration can optimize velocity discrimination of illusory hand movements in line with Bayesian predictions. We ind...
Article
A current challenge for decision-making research is in extending models of simple decisions to more complex and ecological choice situations. Conflict tasks (e.g., Simon, Stroop, Eriksen flanker) have been the focus of much interest, because they provide a decision-making context representative of everyday life experiences. Modeling efforts have le...
Article
Full-text available
Humans are highly sensitive to symmetry. During scene exploration, the area of the retina with dense light receptor coverage acquires most information from relevant locations determined by gaze fixation. We characterised patterns of fixational eye movements made by observers staring at synthetic scenes either freely (i.e. free exploration) or durin...
Article
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...
Article
Full-text available
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...
Chapter
Understanding the effects of various sources of noise and ambiguities can change one's views on the two faces of the sensorimotor transformation. This chapter explains how visual motion information is encoded in neural populations and the relationships between these population activities and behaviors. Second, it summarizes how nonsensory, predicti...
Article
Full-text available
Unlabelled: Most decisions that we make build upon multiple streams of sensory evidence and control mechanisms are needed to filter out irrelevant information. Sequential sampling models of perceptual decision making have recently been enriched by attentional mechanisms that weight sensory evidence in a dynamic and goal-directed way. However, the...
Article
Full-text available
Formal models of decision-making have traditionally focused on simple, two-choice perceptual decisions. To date, one of the most influential account of this process is Ratcliff's drift diffusion model (DDM). However, the extension of the model to more complex decisions is not straightforward. In particular, conflicting situations, such as the Eriks...
Article
Full-text available
Due to the aperture problem, the initial direction of tracking responses to a translating bar is biased towards the direction orthogonal to the bar. This observation offers a powerful way to explore the interactions between retinal and extraretinal signals in controlling our actions. We conducted two experiments to probe these interactions by brief...
Article
The visual system does not process information instantaneously, but rather integrates over time. Integration occurs both for stationary objects and moving objects, with very similar time constants (Burr, 1981). We measured, as a function of exposure duration, speed discrimination and ocular following performance for rich textured motion stimuli of...
Article
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...
Article
Full-text available
Moving objects generate motion information at different scales, which are processed in the visual system with a bank of spatiotemporal frequency channels. It is not known how the brain pools this information to reconstruct object speed and whether this pooling is generic or adaptive; that is, dependent on the behavioral task. We used rich textured...
Article
Full-text available
Sensory responses of the brain are known to be highly variable, but the origin and functional relevance of this variability have long remained enigmatic. Using the variable foreperiod of a visual discrimination task to assess variability in the primate cerebral cortex, we report that visual evoked response variability is not only tied to variabilit...
Data
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Supporting figures and text. (PDF)
Article
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...
Article
Full-text available
Camera-based eye trackers are the mainstay of today's eye movement research and countless practical applications of eye tracking. Recently, a significant impact of changes in pupil size on the accuracy of camera-based eye trackers during fixation has been reported [Wyatt 2010]. We compared the pupil-size effect between a scleral search coil based e...
Article
Countless aspects of visual processing are reflected in eye movements and analyzing eye movements during visual stimulation has become the methodology of choice for many researchers in vision science and beyond. For decades, the scleral searchcoil technique has been considered the “gold standard” in terms of precision and signal to noise ratio, at...
Article
Many neurophysiological studies in monkeys have indicated that visual motion information for the guidance of perception and smooth pursuit eye movements is - at an early stage - processed in the same visual pathway in the brain, crucially involving the middle temporal area (MT). However, these studies left some questions unanswered: Are perception...
Article
Accuracy in estimating an object's global motion over time is not only affected by the noise in visual motion information but also by the spatial limitation of the local motion analyzers (aperture problem). Perceptual and oculomotor data demonstrate that during the initial stages of the motion information processing, 1D motion cues related to the o...
Article
The quality of the estimate of an object's global motion, over time is not only affected by the noise in motion information but also by the spatial limitation of the local motion analyzers (aperture problem). Perceptual and oculomotor data demonstrate that during the initial stages of the motion information processing, 1D motion cues related to the...
Presentation
Predictive information plays a major role in the control of eye movements. When a visual event can be predicted with some confidence the delay to initiate an oculomotor response is reduced and anticipatory movements oriented toward the predicted event can be observed. These effects of predictability unveil the expectancy state (or prior) of the vis...
Conference Paper
Full-text available
We present an ideal observer analysis of single word reading in normal readers and central scotoma patients. Using this technique we are able to predict the spatio-temporal pattern of saccades in terms of pixels. This enables us to contrast theories that are impossible to compare using the traditional letter-slot approaches to modelling reading.
Article
Purpose: Pursuit of a tilted bar has a complex dynamics: tracking is initiated in the direction orthogonal to the bar (1D motion signals) before slowly converging on the actual 2D object motion trajectory. We investigated how 1D and 2D motion signals are combined with internal signals (eye velocity memory or object velocity prediction) related to 2...
Article
During the preparation of a saccadic eye movement a visual stimulus is more efficiently processed when it is spatially coincident with the saccadic target as compared to when the visual and saccadic targets are displayed at different locations. We have previously characterized the time-course of this selective deployment of visual resources (visual...
Conference Paper
Smooth pursuit eye movements in primates unveil the temporal dynamics of 2D motion integration. Tracking of single, tilted bars is always initiated in a direction close to the velocity orthogonal to the bar orientation. This initial bias is gradually reduced: 300ms after visual motion onset both target and eye movement directions are perfectly alig...
Chapter
Full-text available
To accurately track a moving object of interest with appropriate smooth eye movements, the brain needs to reconstruct a single velocity vector describing the global motion of this object. Because of the aperture problem (see Chap. 1), the visual system must integrate piecewise local information from either elongated edges and contours or particular...
Article
We investigated human oculomotor behaviour in a Go–NoGo saccadic task in which the saccadic response to a peripheral visual target was to be inhibited in a minority of trials (NoGo trials). Different from classical experimental paradigms on the inhibitory control of intended actions, in our task the inhibitory cue was identical to the saccadic targ...
Article
Full-text available
Visual processing of color and luminance for smooth pursuit and saccadic eye movements was investigated using a target selection paradigm. In two experiments, stimuli were varied along the dimensions color and luminance, and selection of the more salient target was compared in pursuit and saccades. Initial pursuit was biased in the direction of the...
Article
Full-text available
The quality of the representation of an object's motion is limited by the noise in the sensory input as well as by an intrinsic ambiguity due to the spatial limitation of the visual motion analyzers (aperture problem). Perceptual and oculomotor data demonstrate that motion processing of extended objects is initially dominated by the local 1D motion...
Article
Full-text available
During the preparation of a saccadic eye movement, a visual stimulus is more efficiently processed when it is spatially coincident with the saccadic target as compared to when the visual and the saccadic targets are displayed at different locations. We studied the coupling between visual selective attention and saccadic preparation by measuring ori...
Article
Full-text available
Smooth pursuit eye movements reflect the temporal dynamics of bidimensional (2D) visual motion integration. When tracking a single, tilted line, initial pursuit direction is biased toward unidimensional (1D) edge motion signals, which are orthogonal to the line orientation. Over 200 ms, tracking direction is slowly corrected to finally match the 2D...
Article
Full-text available
The dynamics of attentional deployment before saccade execution was studied with a dual-task paradigm. Observers made a horizontal saccade whose direction was indicated by a symbolic precue and had to discriminate the orientation of a Gabor patch displayed at different delays after the precue (but before saccade onset). The patch location relative...
Article
Researchers have shown that the promptness to initiate a saccade is modulated by countless factors pertaining to the visual context and the task. However, experiments on saccadic eye movements are usually designed in such a way that oculomotor performance is dissociated from the natural role of saccades, namely that of making crucial perceptual inf...
Article
We analyse some of the most important anatomical and functional features emerging at different stages of mammalian brain evolution in terms of a possible computational advantage. At the transition from reptiles to mammals, a major anatomical change occurs in the originally sensory dorsal cortex. The principal layer of pyramidal cells is split by th...
Article
Full-text available
We address the problem of relating thermodynamics to mechanics in the case of microscopic dynamics without a finite time scale. The solution is obtained by expressing the Tsallis entropic index q as a function of the Lévy index α, and using dynamic rather than probabilistic arguments.
Article
The numerical treatment of anomalous diffusion shows that in some cases Hurst's analysis and the second moment technique express the long-range properties by means of distinctly different rescaling coefficients, With theoretical arguments we show this effect to be determined by the finite speed of the propagation front. (C) 1998 Elsevier Science B....

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