scholarly journals The Emergence of Perceived Position in the Visual System

2011 ◽  
Vol 23 (1) ◽  
pp. 119-136 ◽  
Author(s):  
Jason Fischer ◽  
Nicole Spotswood ◽  
David Whitney
Keyword(s):  
Visual System ◽  
Occipital Cortex ◽  
Multivariate Pattern Analysis ◽  
Retinal Position ◽  
Object Position ◽  
Face Area ◽  
Visual Areas ◽  
Position Coding ◽  
Multivariate Pattern ◽  
Spatial Topography

Representing object position is one of the most critical functions of the visual system, but this task is not as simple as reading off an object's retinal coordinates. A rich body of literature has demonstrated that the position in which we perceive an object depends not only on retinotopy but also on factors such as attention, eye movements, object and scene motion, and frames of reference, to name a few. Despite the distinction between perceived and retinal position, strikingly little is known about how or where perceived position is represented in the brain. In the present study, we dissociated retinal and perceived object position to test the relative precision of retina-centered versus percept-centered position coding in a number of independently defined visual areas. In an fMRI experiment, subjects performed a five-alternative forced-choice position discrimination task; our analysis focused on the trials in which subjects misperceived the positions of the stimuli. Using a multivariate pattern analysis to track the coupling of the BOLD response with incremental changes in physical and perceived position, we found that activity in higher level areas—middle temporal complex, fusiform face area, parahippocampal place area, lateral occipital cortex, and posterior fusiform gyrus—more precisely reflected the reported positions than the physical positions of the stimuli. In early visual areas, this preferential coding of perceived position was absent or reversed. Our results demonstrate a new kind of spatial topography present in higher level visual areas in which an object's position is encoded according to its perceived rather than retinal location. We term such percept-centered encoding “perceptotopy”.

scholarly journals Individual face and house-related eye movement patterns distinctively activate FFA and PPA in the absence of faces and houses

2019 ◽  
Author(s):  
Lihui Wang ◽  
Florian Baumgartner ◽  
Falko R. Kaule ◽  
Michael Hanke ◽  
Stefan Pollmann
Keyword(s):  
Pattern Analysis ◽  
Perception And Action ◽  
Fusiform Face Area ◽  
Multivariate Pattern Analysis ◽  
Face Area ◽  
Gaze Patterns ◽  
Visual Areas ◽  
Uniform Background ◽  
Multivariate Pattern ◽  
Parahippocampal Place Area

We investigated if the fusiform face area (FFA) and the parahippocampal place area (PPA) contain a representation of fixation sequences that are typically used when looking at faces or houses. For this purpose, we instructed observers to follow a dot presented on a uniform background. The dot's movements represented gaze paths acquired separately while observers were looking at face or house pictures. Even when gaze dispersion differences were controlled, face- and house-associated gaze patterns could be discriminated by multivariate pattern analysis in the FFA and PPA. The discrimination of face- and house-associated gaze patterns in FFA and PPA was more sensitive for the current observer’s own gazes than for another observer’s gaze. Moreover, the discrimination of the observer’s own gaze patterns was specific to FFA and PPA, but was not observed in early visual areas (V1 – V4) or superior parietal lobule and frontal eye fields. These findings indicate a link between perception and action - the complex gaze patterns that are used to explore faces and houses - in the FFA and PPA.

scholarly journals Individual face- and house-related eye movement patterns distinctively activate FFA and PPA

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lihui Wang ◽  
Florian Baumgartner ◽  
Falko R. Kaule ◽  
Michael Hanke ◽  
Stefan Pollmann
Keyword(s):  
Pattern Analysis ◽  
Perception And Action ◽  
Fusiform Face Area ◽  
Multivariate Pattern Analysis ◽  
Face Area ◽  
Gaze Patterns ◽  
Visual Areas ◽  
Uniform Background ◽  
Multivariate Pattern ◽  
Parahippocampal Place Area

AbstractWe investigated if the fusiform face area (FFA) and the parahippocampal place area (PPA) contain a representation of fixation sequences that are typically used when looking at faces or houses. Here, we instructed observers to follow a dot presented on a uniform background. The dot’s movements represented gaze paths acquired separately from observers looking at face or house pictures. Even when gaze dispersion differences were controlled, face- and house-associated gaze patterns could be discriminated by fMRI multivariate pattern analysis in FFA and PPA, more so for the current observer’s own gazes than for another observer’s gaze. The discrimination of the observer’s own gaze patterns was not observed in early visual areas (V1 – V4) or superior parietal lobule and frontal eye fields. These findings indicate a link between perception and action—the complex gaze patterns that are used to explore faces and houses—in the FFA and PPA.

scholarly journals Neural correlates of conscious visual perception lie outside the visual system: evidence from the double-drift illusion

2019 ◽  
Author(s):  
Sirui Liu ◽  
Qing Yu ◽  
Peter U. Tse ◽  
Patrick Cavanagh
Keyword(s):  
Visual System ◽  
Visual Processing ◽  
Pattern Analysis ◽  
Activity Patterns ◽  
Neural Correlates ◽  
Multivariate Pattern Analysis ◽  
Visual Areas ◽  
Visual Cortices ◽  
Multivariate Pattern ◽  
The Brain

SummaryWhen perception differs from the physical stimulus, as it does for visual illusions and binocular rivalry, the opportunity arises to localize where perception emerges in the visual processing hierarchy. Representations prior to that stage differ from the eventual conscious percept even though they provide input to it. Here we investigate where and how a remarkable misperception of position emerges in the brain. This “double-drift” illusion causes a dramatic mismatch between retinal and perceived location, producing a perceived path that can differ from its physical path by 45° or more [1]. The deviations in the perceived trajectory can accumulate over at least a second [1] whereas other motion-induced position shifts accumulate over only 80 to 100 ms before saturating [2]. Using fMRI and multivariate pattern analysis, we find that the illusory path does not share activity patterns with a matched physical path in any early visual areas. In contrast, a whole-brain searchlight analysis reveals a shared representation in more anterior regions of the brain. These higher-order areas would have the longer time constants required to accumulate the small moment-to-moment position offsets that presumably originate in early visual cortices, and then transform these sensory inputs into a final conscious percept. The dissociation between perception and the activity in early sensory cortex suggests that perceived position does not emerge in what is traditionally regarded as the visual system but emerges instead at a much higher level.

Revisiting the Role of the Fusiform Face Area in Expertise

2016 ◽  
Vol 28 (9) ◽  
pp. 1345-1357 ◽  
Author(s):  
Merim Bilalić
Keyword(s):  
Pattern Analysis ◽  
Spatial Relations ◽  
Fusiform Face Area ◽  
Multivariate Pattern Analysis ◽  
Multiple Objects ◽  
Activation Patterns ◽  
Face Area ◽  
Single Category ◽  
Multivariate Pattern

The fusiform face area (FFA) is considered to be a highly specialized brain module because of its central importance for face perception. However, many researchers claim that the FFA is a general visual expertise module that distinguishes between individual examples within a single category. Here, I circumvent the shortcomings of some previous studies on the FFA controversy by using chess stimuli, which do not visually resemble faces, together with more sensitive methods of analysis such as multivariate pattern analysis. I also extend the previous research by presenting chess positions, complex scenes with multiple objects, and their interrelations to chess experts and novices as well as isolated chess objects. The first experiment demonstrates that chess expertise modulated the FFA activation when chess positions were presented. In contrast, single chess objects did not produce different activation patterns among experts and novices even when the multivariate pattern analysis was used. The second experiment focused on the single chess objects and featured an explicit task of identifying the chess objects but failed to demonstrate expertise effects in the FFA. The experiments provide support for the general expertise view of the FFA function but also extend the scope of our understanding about the function of the FFA. The FFA does not merely distinguish between different exemplars within the same category of stimuli. More likely, it parses complex multiobject stimuli that contain numerous functional and spatial relations.

Single Units and Visual Cortical Organization

Perception ◽  
1998 ◽  
Vol 27 (8) ◽  
pp. 889-935 ◽  
Author(s):  
Peter Lennie
Keyword(s):  
Visual System ◽  
Striate Cortex ◽  
Occipital Cortex ◽  
Relevant Information ◽  
Hierarchical Organization ◽  
Cortical Organization ◽  
Visual Areas ◽  
The World ◽  
Visual Cortical ◽  
Extrastriate Areas

The visual system has a parallel and hierarchical organization, evident at every stage from the retina onwards. Although the general benefits of parallel and hierarchical organization in the visual system are easily understood, it has not been easy to discern the function of the visual cortical modules. I explore the view that striate cortex segregates information about different attributes of the image, and dispatches it for analysis to different extrastriate areas. I argue that visual cortex does not undertake multiple relatively independent analyses of the image from which it assembles a unified representation that can be interrogated about the what and where of the world. Instead, occipital cortex is organized so that perceptually relevant information can be recovered at every level in the hierarchy, that information used in making decisions at one level is not passed on to the next level, and, with one rather special exception (area MT), through all stages of analysis all dimensions of the image remain intimately coupled in a retinotopic map. I then offer some explicit suggestions about the analyses undertaken by visual areas in occipital cortex, and conclude by examining some objections to the proposals.

scholarly journals Mapping brain activation and information during category-specific visual working memory

2012 ◽  
Vol 107 (2) ◽  
pp. 628-639 ◽  
Author(s):  
David E. J. Linden ◽  
Nikolaas N. Oosterhof ◽  
Christoph Klein ◽  
Paul E. Downing
Keyword(s):  
Working Memory ◽  
Cortical Activation ◽  
Multivariate Pattern Analysis ◽  
Frontoparietal Network ◽  
Visual Areas ◽  
Occipitotemporal Cortex ◽  
Initial Processing ◽  
Multivariate Pattern ◽  
The Brain ◽  
Term Maintenance

How is working memory for different visual categories supported in the brain? Do the same principles of cortical specialization that govern the initial processing and encoding of visual stimuli also apply to their short-term maintenance? We investigated these questions with a delayed discrimination paradigm for faces, bodies, flowers, and scenes and applied both univariate and multivariate analyses to functional magnetic resonance imaging (fMRI) data. Activity during encoding followed the well-known specialization in posterior areas. During the delay interval, activity shifted to frontal and parietal regions but was not specialized for category. Conversely, activity in visual areas returned to baseline during that interval but showed some evidence of category specialization on multivariate pattern analysis (MVPA). We conclude that principles of cortical activation differ between encoding and maintenance of visual material. Whereas perceptual processes rely on specialized regions in occipitotemporal cortex, maintenance involves the activation of a frontoparietal network that seems to require little specialization at the category level. We also confirm previous findings that MVPA can extract information from fMRI signals in the absence of suprathreshold activation and that such signals from visual areas can reflect the material stored in memory.

scholarly journals Investigating the Impact of the Missing Significant Objects in Scene Recognition Using Multivariate Pattern Analysis

2020 ◽  
Vol 14 ◽  
Author(s):  
Jin Gu ◽  
Baolin Liu ◽  
Weiran Yan ◽  
Qiaomu Miao ◽  
Jianguo Wei
Keyword(s):  
Pattern Analysis ◽  
Spatial Information ◽  
Occipital Cortex ◽  
Scene Recognition ◽  
Multivariate Pattern Analysis ◽  
Lateral Occipital Complex ◽  
Average Signal Intensity ◽  
Multivariate Pattern ◽  
The Impact ◽  
Lateral Occipital Cortex

Significant objects in a scene can make a great contribution to scene recognition. Besides the three scene-selective regions: parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area (OPA), some neuroimaging studies have shown that the lateral occipital complex (LOC) is also engaged in scene recognition processing. In this study, the multivariate pattern analysis was adopted to explore the object-scene association in scene recognition when different amounts of significant objects were masked. The scene classification only succeeded in the intact scene in the ROIs. In addition, the average signal intensity in LOC [including the lateral occipital cortex (LO) and the posterior fusiform area (pF)] decreased when there were masked objects, but such a decrease was not observed in scene-selective regions. These results suggested that LOC was sensitive to the loss of significant objects and mainly involved in scene recognition by the object-scene semantic association. The performance of the scene-selective areas may be mainly due to the fact that they responded to the change of the scene's entire attribute, such as the spatial information, when they were employed in the scene recognition processing. These findings further enrich our knowledge of the significant objects' influence on the activation pattern during the process of scene recognition.

scholarly journals Real-world structure facilitates the rapid emergence of scene category information in visual brain signals

2020 ◽  
Author(s):  
Daniel Kaiser ◽  
Greta Häberle ◽  
Radoslaw M. Cichy
Keyword(s):  
Visual System ◽  
Real World ◽  
Visual Processing ◽  
Relevant Information ◽  
Natural Environments ◽  
Multivariate Pattern Analysis ◽  
Categorical Analysis ◽  
Category Information ◽  
Brain Signals ◽  
Multivariate Pattern

AbstractIn everyday life, our visual surroundings are not arranged randomly, but structured in predictable ways. Although previous studies have shown that the visual system is sensitive to such structural regularities, it remains unclear whether the presence of an intact structure in a scene also facilitates the cortical analysis of the scene’s categorical content. To address this question, we conducted an EEG experiment during which participants viewed natural scene images that were either “intact” (with their quadrants arranged in typical positions) or “jumbled” (with their quadrants arranged into atypical positions). We then used multivariate pattern analysis to decode the scenes’ category from the EEG signals (e.g., whether the participant had seen a church or a supermarket). The category of intact scenes could be decoded rapidly within the first 100ms of visual processing. Critically, within 200ms of processing category decoding was more pronounced for the intact scenes compared to the jumbled scenes, suggesting that the presence of real-world structure facilitates the extraction of scene category information. No such effect was found when the scenes were presented upside-down, indicating that the facilitation of neural category information is indeed linked to a scene’s adherence to typical real-world structure, rather than to differences in visual features between intact and jumbled scenes. Our results demonstrate that early stages of categorical analysis in the visual system exhibit tuning to the structure of the world that may facilitate the rapid extraction of behaviorally relevant information from rich natural environments.

scholarly journals How attention extracts objects from noise

2013 ◽  
Vol 110 (6) ◽  
pp. 1346-1356 ◽  
Author(s):  
Michael S. Pratte ◽  
Sam Ling ◽  
Jascha D. Swisher ◽  
Frank Tong
Keyword(s):  
Visual Processing ◽  
Activity Patterns ◽  
Occipital Cortex ◽  
Relevant Information ◽  
Visual Input ◽  
Visual Noise ◽  
Noise Filtering ◽  
Area V4 ◽  
Face Area ◽  
Visual Areas

The visual system is remarkably proficient at extracting relevant object information from noisy, cluttered environments. Although attention is known to enhance sensory processing, the mechanisms by which attention extracts relevant information from noise are not well understood. According to the perceptual template model, attention may act to amplify responses to all visual input, or it may act as a noise filter, dampening responses to irrelevant visual noise. Amplification allows for improved performance in the absence of visual noise, whereas a noise-filtering mechanism can only improve performance if the target stimulus appears in noise. Here, we used fMRI to investigate how attention modulates cortical responses to objects at multiple levels of the visual pathway. Participants viewed images of faces, houses, chairs, and shoes, presented in various levels of visual noise. We used multivoxel pattern analysis to predict the viewed object category, for attended and unattended stimuli, from cortical activity patterns in individual visual areas. Early visual areas, V1 and V2, exhibited a benefit of attention only at high levels of visual noise, suggesting that attention operates via a noise-filtering mechanism at these early sites. By contrast, attention led to enhanced processing of noise-free images (i.e., amplification) only in higher visual areas, including area V4, fusiform face area, mid-Fusiform area, and the lateral occipital cortex. Together, these results suggest that attention improves people's ability to discriminate objects by de-noising visual input in early visual areas and amplifying this noise-reduced signal at higher stages of visual processing.

scholarly journals Effects of Literacy in Early Visual and Occipitotemporal Areas of Chinese and French Readers

2014 ◽  
Vol 26 (3) ◽  
pp. 459-475 ◽  
Author(s):  
Marcin Szwed ◽  
Emilie Qiao ◽  
Antoinette Jobert ◽  
Stanislas Dehaene ◽  
Laurent Cohen
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Reading Skills ◽  
Occipital Cortex ◽  
Group Differences ◽  
Visual Word Form Area ◽  
Visual Areas ◽  
Fast Processing ◽  
Reading Chinese ◽  
French Words

How does reading expertise change the visual system? Here, we explored whether the visual system could develop dedicated perceptual mechanisms in early and intermediate visual cortex under the pressure for fast processing that is particularly strong in reading. We compared fMRI activations in Chinese participants with limited knowledge of French and in French participants with no knowledge of Chinese, exploiting these doubly dissociated reading skills as a tool to study the neural correlates of visual expertise. All participants viewed the same stimuli: words in both languages and matched visual controls, presented at a fast rate comparable with fluent reading. In the Visual Word Form Area, all participants showed enhanced responses to their known scripts. However, group differences were found in occipital cortex. In French readers reading French, activations were enhanced in left-hemisphere visual area V1, with the strongest differences between French words and their controls found at the central and horizontal meridian representations. Chinese participants, who were not expert French readers, did not show these early visual activations. In contrast, Chinese readers reading Chinese showed enhanced activations in intermediate visual areas V3v/hV4, absent in French participants. Together with our previous findings [Szwed, M., Dehaene, S., Kleinschmidt, A., Eger, E., Valabregue, R., Amadon, A., et al. Specialization for written words over objects in the visual cortex. Neuroimage, 56, 330–344, 2011], our results suggest that the effects of extensive practice can be found at the lowest levels of the visual system. They also reveal their cross-script variability: Alphabetic reading involves enhanced engagement of central and right meridian V1 representations that are particularly used in left-to-right reading, whereas Chinese characters put greater emphasis on intermediate visual areas.

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