Marco Boi

Marco Boi
Boston University | BU · Department of Psychology

About

36
Publications
845
Reads
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203
Citations
Introduction
Additional affiliations
November 2006 - December 2010
École Polytechnique Fédérale de Lausanne
Position
  • Non-Retinotopic Processing
Description
  • Visual Stability Eye Movements Motion Attention Motion Aftereffect Tilt Aftereffect Exogenous Attention Visual Search Saliency Maps
Education
November 2006 - December 2010
École Polytechnique Fédérale de Lausanne
Field of study
  • Visual Neuroscience

Publications

Publications (36)
Article
Full-text available
Humans use rapid gaze shifts, known as saccades, to explore visual scenes. These movements yield abrupt luminance changes on the retina, which elicit robust neural discharges at fixation onsets. Yet little is known about the spatial content of saccade transients. Here, we show that saccades redistribute spatial information within the temporal range...
Article
Much evidence indicates that humans and other species process large-scale visual information before fine spatial detail. Neurophysiological data obtained with paralyzed eyes suggest that this coarse-to-fine sequence results from spatiotemporal filtering by neurons in the early visual pathway. However, the eyes are normally never stationary: rapid g...
Article
Magnocellular and parvocellular neurons in the retina and lateral geniculate nucleus tend to prefer complementary spatial frequency ranges, with magnocellular neurons sensitive to lower frequencies than parvocellular ones. Interestingly, these neurons also exhibit different temporal preferences: magnocellular neurons tend to be more responsive to t...
Article
Under natural viewing conditions, fast relocations of gaze (saccades) separate brief periods of "fixation", in which microscopic eye movements continually occur. It is well known that the visual system is highly sensitive to temporal transients, and we have previously shown that fixational instability equalizes the amplitude of the luminance modula...
Article
Full-text available
Like all saccades, microsaccades cause both spatial and temporal changes in the input to the retina. In space, recent studies have shown that these small shifts precisely relocate a narrow (smaller than the foveola) high-acuity retinal locus on the stimulus. However, it has long been questioned whether the temporal modulations resulting from micros...
Article
In binocular rivalry, only one image is perceived consciously when different, incompatible images are presented to the left and right eye, respectively. The other image is suppressed. Binocular suppression is generally assumed to occur within retinotopic coordinates. However, the world is continuously shifting on our retina because of the movements...
Article
Attention is crucial for visual perception because it allows the visual system to effectively use its limited resources by selecting behaviorally and cognitively relevant stimuli from the large amount of information impinging on the eyes. Reflexive, stimulus-driven attention is essential for successful interactions with the environment because it c...
Article
Recent studies have shown that a variety of aftereffects occurs in a non-retinotopic frame of reference. These findings have been taken as strong evidence that remapping of visual information occurs in a hierarchic manner in the human cortex with an increasing magnitude from early to higher levels. Other studies, however, failed to find non-retinot...
Article
Several experiments on human subjects evidenced how they are endowed with a good ability to recognize unambiguously a motor action, whilst they are not able to recognize without uncertainty an action from a single image frame representing the same action. In fact, the movement is a motion characterized by a whole spatio-temporal pattern, with speci...
Article
Purpose: To study a new Illusion of misalignment. Given a two-dimensional configuration made up of a white vertical rectangle partially occluded by a black horizontal one, so that the two extreme components of the occluded rectangle remain visible, when the figure is monocularly viewed, the two components, geometrically aligned, appear misaligned....
Article
Attentional capture by an exogenous spatial-cue is generally believed to be mediated by retinotopic mechanisms. Using a Ternus-Pikler display, we show that attentional capture occurs in non-retinotopic coordinates. In a first frame, three squares were presented for 200ms followed by a 70ms ISI and a second frame containing the same three squares sh...
Article
At the heart of feature integration theory there is a master map that operates on the various features maps. Explicitly or implicitly, it is assumed that these feature maps are organized retinotopically. If in conjunction search, for example, a horizontal green line must be found, the master map would look at the retinotopic position (x,y) in both...
Article
A novel motion illusion is shown consisting of a white circle moving across or behind black parallel lines on a grey background. When the gaze is kept on the centre of the circle, the circle appears to rotate even if it is, in fact, translating. The apparent motion can only be perceived in peripheral vision. Phenomenology of the illusion: (i) the r...
Article
An array of black discs surrounded by a set of coloured annuli forming a ramp, whose luminance increases outward, is perceived scintillating of complementary colours when moving the gaze from an element to another. We call this illusion Coloured Flashing Spots (CFS). It differs from simple colour contrast in being vivid, self luminous and lustrous,...
Article
At every moment, the image the world projects on our eyes undergoes rapid and dramatic changes due to the eye movements and to the motion of the objects. Surprisingly, we are not aware of these changes, experiencing the world as stable and constant. This apparent contradiction suggests that our visual system uses non-retinotopic representations of...
Article
Full-text available
In human vision, the optics of the eye map neighboring points of the environment onto neighboring photoreceptors in the retina. This retinotopic encoding principle is preserved in the early visual areas. Under normal viewing conditions, due to the motion of objects and to eye movements, the retinotopic representation of the environment undergoes fa...
Article
At the heart of feature integration theory is a master map which operates on dimension-based feature maps. It is assumed that these feature maps are organized retinotopically. If in conjunction search, for example, a horizontal green line has to be searched for, the master map 'looks' at the retinotopic position (x,y) in both the color and the orie...
Article
Most visual cortical areas are retinotopically organized and accordingly most visual processing is assumed to be processed within a retinotopic coordinate frame. However, in a series of psychophysical experiments, we have shown that features of elements are often non-retinotopically integrated when the corresponding elements are motion grouped. Whe...
Article
Motion processing is usually deemed to rely on retinotopic coordinates. Using a Ternus-Pikler display, we present an instance in which coherent motion of a dot can only be perceived when its position is integrated non-retinotopically. The stimulus consists of a traditional Ternus-Pikler display where three discs are perceived to move back and forth...
Chapter
In this paper we are interested in the perceptual aspect of face recognition that is the process that categorizes the visually perceived face into a perceptive space made by as many categories as the possible discriminations are. The question we want to answer to is if it is possible to model some aspect of face perception using a neural network ar...
Article
Distinctiveness is the ease with which a particular exemplar can be recognized among similar ones. In humans, face distinctiveness is related to a facilitation in recognition: in particular (Valentine and Bruce,1986 Perception 15 525-535; Light et al, 1979 Journal of Experimental Psychology 5 212-228) atypical faces seems to be recognized better an...

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Projects

Project (1)
Project
Visual information is not just encoded by the position of receptive fields; luminance transients caused by eye movements play a critical role.