From Knowing What to Knowing Where: Modeling Object-Based Attention with Feedback Disinhibition of Activation

2001 ◽  
Vol 13 (4) ◽  
pp. 479-491 ◽  
Author(s):  
Frank van der Velde ◽  
Marc de Kamps
Keyword(s):  
Dorsal Stream ◽  
Gain Control ◽  
Neural Model ◽  
Ventral Stream ◽  
Visual Object ◽  
Selective Activation ◽  
Visual Stream ◽  
Search Tasks ◽  
Object Based ◽  
Feedback Activation

We propose a neural model of visual object-based attention in which the identity of an object is used to select its location in an array of objects. The model is based on neural activity observed in visual search tasks performed by monkeys. In the model, the identity of the object (target) is selected in the higher areas of the ventral stream by means of a cue. Feedback activation from these higher areas carries information about the identity of the target to the (lower) retinotopic areas of the ventral stream. In these areas, the feedback activation interacts with feedforward activation produced by the object array. The interaction occurs in local microcircuits, and results in a selective activation on locations in the retinotopic areas of the visual stream that correspond to the location of the target in the object array. The selective activation consists of a form of gain control, produced by disinhibition. Transmitted to the dorsal stream, this activation directs spatial attention to the location of the target. In this way, an action directed at the target can be generated.

Asynchronies in the Development of Electrophysiological Responses to Motion and Color

2004 ◽  
Vol 16 (8) ◽  
pp. 1363-1374 ◽  
Author(s):  
Teresa V. Mitchell ◽  
Helen J. Neville
Keyword(s):  
Time Course ◽  
Behavioral Plasticity ◽  
Dorsal Stream ◽  
Event Related Potentials ◽  
Developmental Time ◽  
Ventral Stream ◽  
Visual Stream ◽  
Age Related ◽  
Electrophysiological Responses ◽  
Related Potentials

Recent reports have documented greater plasticity in the dorsal visual stream as compared with the ventral visual stream. This study sought to test the hypothesis that this greater plasticity may be related to a more protracted period of development in the dorsal as compared with the ventral stream. Age-related effects on event-related potentials (ERPs) elicited by motion and color stimuli, designed to activate the two visual streams, were assessed in healthy individuals aged 6 years through adulthood. Although significant developmental effects were observed in amplitudes of ERPs to both color and motion stimuli, marked latency effects were observed only in response to motion. These results provide support for the hypothesis that the dorsal stream displays a longer developmental time course across the early school years than the ventral stream. Implications for neural and behavioral plasticity are discussed.

Functional Reorganization of the Visual Dorsal Stream as Probed by 3-D Visual Coherence in Williams Syndrome

2014 ◽  
Vol 26 (11) ◽  
pp. 2624-2636 ◽  
Author(s):  
Inês Bernardino ◽  
José Rebola ◽  
Reza Farivar ◽  
Eduardo Silva ◽  
Miguel Castelo-Branco
Keyword(s):  
Williams Syndrome ◽  
Visual Information ◽  
Dorsal Stream ◽  
Occipital Cortex ◽  
Retrosplenial Cortex ◽  
Ventral Stream ◽  
Object Categorization ◽  
Depth Information ◽  
Visual Stream ◽  
Dorsal Pathway

Object and depth perception from motion cues involves the recruitment of visual dorsal stream brain areas. In 3-D structure-from-motion (SFM) perception, motion and depth information are first extracted in this visual stream to allow object categorization, which is in turn mediated by the ventral visual stream. Such interplay justifies the use of SFM paradigms to understand dorsal–ventral integration of visual information. The nature of such processing is particularly interesting to be investigated in a neurological model of cognitive dissociation between dorsal (impaired) and ventral stream (relatively preserved) processing, Williams syndrome (WS). In the current fMRI study, we assessed dorsal versus ventral stream processing by using a performance-matched 3-D SFM object categorization task. We found evidence for substantial reorganization of the dorsal stream in WS as assessed by whole-brain ANOVA random effects analysis, with subtle differences in ventral activation. Dorsal reorganization was expressed by larger medial recruitment in WS (cuneus, precuneus, and retrosplenial cortex) in contrast with controls, which showed the expected dorsolateral pattern (caudal intraparietal sulcus and lateral occipital cortex). In summary, we found a substantial reorganization of dorsal stream regions in WS in response to simple visual categories and 3-D SFM perception, with less affected ventral stream. Our results corroborate the existence of a medial dorsal pathway that provides the substrate for information rerouting and reorganization in the presence of lateral dorsal stream vulnerability. This interpretation is consistent with recent findings suggesting parallel routing of information in medial and lateral parts of dorsal stream.

scholarly journals A performance-optimized model of neural responses across the ventral visual stream

2016 ◽  
Author(s):  
Darren Seibert ◽  
Daniel L Yamins ◽  
Diego Ardila ◽  
Ha Hong ◽  
James J DiCarlo ◽  
...  
Keyword(s):  
Neural Network ◽  
Visual Cortex ◽  
Object Recognition ◽  
Recognition Performance ◽  
Ventral Stream ◽  
Visual Object ◽  
Emergent Properties ◽  
Visual Stream ◽  
Response Properties ◽  
High Level

Human visual object recognition is subserved by a multitude of cortical areas. To make sense of this system, one line of research focused on response properties of primary visual cortex neurons and developed theoretical models of a set of canonical computations such as convolution, thresholding, exponentiating and normalization that could be hierarchically repeated to give rise to more complex representations. Another line or research focused on response properties of high-level visual cortex and linked these to semantic categories useful for object recognition. Here, we hypothesized that the panoply of visual representations in the human ventral stream may be understood as emergent properties of a system constrained both by simple canonical computations and by top-level, object recognition functionality in a single unified framework (Yamins et al., 2014; Khaligh-Razavi and Kriegeskorte, 2014; Guclu and van Gerven, 2015). We built a deep convolutional neural network model optimized for object recognition and compared representations at various model levels using representational similarity analysis to human functional imaging responses elicited from viewing hundreds of image stimuli. Neural network layers developed representations that corresponded in a hierarchical consistent fashion to visual areas from V1 to LOC. This correspondence increased with optimization of the model's recognition performance. These findings support a unified view of the ventral stream in which representations from the earliest to the latest stages can be understood as being built from basic computations inspired by modeling of early visual cortex shaped by optimization for high-level object-based performance constraints.

scholarly journals Wiring Up Vision: Minimizing Supervised Synaptic Updates Needed to Produce a Primate Ventral Stream

2020 ◽  
Author(s):  
Franziska Geiger ◽  
Martin Schrimpf ◽  
Tiago Marques ◽  
James J. DiCarlo
Keyword(s):  
Visual System ◽  
Visual Processing ◽  
Ventral Stream ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Visual Stream ◽  
Ongoing Research ◽  
Ventral Visual Stream ◽  
And Behavior ◽  
The Brain

AbstractAfter training on large datasets, certain deep neural networks are surprisingly good models of the neural mechanisms of adult primate visual object recognition. Nevertheless, these models are poor models of the development of the visual system because they posit millions of sequential, precisely coordinated synaptic updates, each based on a labeled image. While ongoing research is pursuing the use of unsupervised proxies for labels, we here explore a complementary strategy of reducing the required number of supervised synaptic updates to produce an adult-like ventral visual stream (as judged by the match to V1, V2, V4, IT, and behavior). Such models might require less precise machinery and energy expenditure to coordinate these updates and would thus move us closer to viable neuroscientific hypotheses about how the visual system wires itself up. Relative to the current leading model of the adult ventral stream, we here demonstrate that the total number of supervised weight updates can be substantially reduced using three complementary strategies: First, we find that only 2% of supervised updates (epochs and images) are needed to achieve ~80% of the match to adult ventral stream. Second, by improving the random distribution of synaptic connectivity, we find that 54% of the brain match can already be achieved “at birth” (i.e. no training at all). Third, we find that, by training only ~5% of model synapses, we can still achieve nearly 80% of the match to the ventral stream. When these three strategies are applied in combination, we find that these new models achieve ~80% of a fully trained model’s match to the brain, while using two orders of magnitude fewer supervised synaptic updates. These results reflect first steps in modeling not just primate adult visual processing during inference, but also how the ventral visual stream might be “wired up” by evolution (a model’s “birth” state) and by developmental learning (a model’s updates based on visual experience).

scholarly journals Lessons from human vision for robotic design

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Melvyn A. Goodale
Keyword(s):  
Visual Information ◽  
Posterior Parietal Cortex ◽  
Temporal Cortex ◽  
Dorsal Stream ◽  
Division Of Labour ◽  
Ventral Stream ◽  
Human Vision ◽  
Visual Stream ◽  
Course Of Action ◽  
The World

AbstractThe visual guidance of goal-directed movements requires transformations of incoming visual information that are different from those required for visual perception. For us to grasp an object successfully, our brain must use just-in-time computations of the object’s real-world size and shape, and its orientation and disposition with respect to our hand. These requirements have led to the emergence of dedicated visuomotor modules in the posterior parietal cortex of the human brain (the dorsal visual stream) that are functionally distinct from networks in the occipito-temporal cortex (the ventral visual stream) that mediate our conscious perception of the world. Although the identification and selection of goal objects and an appropriate course of action depends on the perceptual machinery of the ventral stream and associated cognitive modules, the execution of the subsequent goal-directed action is mediated by dedicated online control systems in the dorsal stream and associated motor areas. The dorsal stream allows an observer to reach out and grasp objects with exquisite ease, but by itself, deals only with objects that are visible at the moment the action is being programmed. The ventral stream, however, allows an observer to escape the present and bring to bear information from the past – including information about the function of objects, their intrinsic properties, and their location with reference to other objects in the world. Ultimately then, both streams contribute to the production of goal-directed actions. The principles underlying this division of labour between the dorsal and ventral streams are relevant to the design and implementation of autonomous robotic systems.

scholarly journals The role of posterior ventral stream areas for viewpoint-invariant object recognition

2021 ◽  
Author(s):  
Sophia Nestmann ◽  
Hans-Otto Karnath ◽  
Johannes Rennig
Keyword(s):  
Object Recognition ◽  
Object Perception ◽  
Ventral Stream ◽  
Visual Object ◽  
Visual Stream ◽  
Activation Patterns ◽  
Object Constancy ◽  
Invariant Object Recognition ◽  
Fmri Experiment ◽  
The Right

Object constancy is one of the most crucial mechanisms of the human visual system enabling viewpoint invariant object recognition. However, the neuronal foundations of object constancy are widely unknown. Research has shown that the ventral visual stream is involved in processing of various kinds of object stimuli and that several regions along the ventral stream are possibly sensitive to the orientation of an object in space. To systematically address the question of viewpoint sensitive object perception, we conducted a study with stroke patients as well as an fMRI experiment with healthy participants applying object stimuli in several spatial orientations, for example in typical and atypical viewing conditions. In the fMRI experiment, we found stronger BOLD signals and above-chance classification accuracies for objects presented in atypical viewing conditions in fusiform face sensitive and lateral occipito-temporal object preferring areas. In the behavioral patient study, we observed that lesions of the right fusiform gyrus were associated with lower performance in object recognition for atypical views. The complementary results from both experiments emphasize the contributions of fusiform and lateral-occipital areas to visual object constancy and indicate that visual object constancy is particularly enabled through increased neuronal activity and specific activation patterns for objects in demanding viewing conditions.

scholarly journals Detecting Diffusion Imaging constructive connectivity analysis for What stream Visual Pathways with correlations to Visual Agnosia

2018 ◽  
Author(s):  
GANESH ELUMALAI ◽  
Geethanjali Vinodhanand ◽  
Valencia Lasandra Camoya Brown ◽  
Jessica Dasari ◽  
Venkata Hari Krishna Kurra ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Perception ◽  
Structural Connectivity ◽  
Visual Pathways ◽  
Ventral Stream ◽  
Visual Object ◽  
Visual Agnosia ◽  
Visual Stream ◽  
Observational Analysis ◽  
Inferior Temporal Gyrus

Visual perception is the ability to interpret the surrounding environment. A hypothetical ventral stream visual pathway explains how we perceive objects with respect to spatial orientation. The ventral stream fibers extend between Visual cortex to Inferior temporal gyrus. The previous studies have failed to prove any indications on the structural connectivity of this pathway. This study is designed to trace the existence of neural structural connectivity between Visual cortex with Inferior temporal gyrus using Diffusion Tensor Imaging Tractography, which aims to correlate its functional importance with visual object perception. The observational analysis used thirty two healthy adults, ultrahigh b-value and diffusion MRI datasets from an Open access research platform. The datasets range from both sexes, between 20 to 49 years, with mean age of 30.4 years. The confirmatory observational analysis process includes datasets acquisition, pre-processing, processing, reconstruction, fiber tractography and analysis using software tools. All the datasets confirmed the fibre structural extension between, Visual cortex to Inferior temporal gyrus in both the sexes may responsible for the visual perception of objects. This new fiber connectivity evidence justifies the structural relevance of visual perception impairments, such as visual object agnosia. Keywords: Ventral Visual Stream, Dorsal Visual Stream, Visual Agnosia, Where visual pathways

scholarly journals “Real-time” obstacle avoidance in the absence of primary visual cortex

2009 ◽  
Vol 106 (37) ◽  
pp. 15996-16001 ◽  
Author(s):  
Christopher L. Striemer ◽  
Craig S. Chapman ◽  
Melvyn A. Goodale
Keyword(s):  
Visual Cortex ◽  
Real Time ◽  
Obstacle Avoidance ◽  
Primary Visual Cortex ◽  
Posterior Parietal Cortex ◽  
Dorsal Stream ◽  
Visual Pathways ◽  
Visual Stream ◽  
Reaching Task ◽  
Visual Inputs

When we reach toward objects, we easily avoid potential obstacles located in the workspace. Previous studies suggest that obstacle avoidance relies on mechanisms in the dorsal visual stream in the posterior parietal cortex. One fundamental question that remains unanswered is where the visual inputs to these dorsal-stream mechanisms are coming from. Here, we provide compelling evidence that these mechanisms can operate in “real-time” without direct input from primary visual cortex (V1). In our first experiment, we used a reaching task to demonstrate that an individual with a dense left visual field hemianopia after damage to V1 remained strikingly sensitive to the position of unseen static obstacles placed in his blind field. Importantly, in a second experiment, we showed that his sensitivity to the same obstacles in his blind field was abolished when a short 2-s delay (without vision) was introduced before reach onset. These findings have far-reaching implications, not only for our understanding of the time constraints under which different visual pathways operate, but also in relation to how these seemingly “primitive” subcortical visual pathways can control complex everyday behavior without recourse to conscious vision.

scholarly journals Sound-identity processing in early areas of the auditory ventral stream in the macaque

2012 ◽  
Vol 107 (4) ◽  
pp. 1123-1141 ◽  
Author(s):  
Paweł Kuśmierek ◽  
Michael Ortiz ◽  
Josef P. Rauschecker
Keyword(s):  
Rhesus Macaques ◽  
Population Analysis ◽  
Activity Patterns ◽  
Dorsal Stream ◽  
Stimulus Onset ◽  
Ventral Stream ◽  
Underlying Mechanisms ◽  
Species Specific ◽  
Rostral Region ◽  
Identity Processing

Auditory cortical processing is thought to be accomplished along two processing streams. The existence of a posterior/dorsal stream dealing, among others, with the processing of spatial aspects of sound has been corroborated by numerous studies in several species. An anterior/ventral stream for the processing of nonspatial sound qualities, including the identification of sounds such as species-specific vocalizations, has also received much support. Originally discovered in anterolateral belt cortex, most recent work on the anterior/ventral pathway has been performed on far anterior superior temporal (ST) areas and on ventrolateral prefrontal cortex (VLPFC). Regions of the anterior/ventral stream near its origin in early auditory areas have been less explored. In the present study, we examined three early auditory regions with different anteroposterior locations (caudal, middle, and rostral) in awake rhesus macaques. We analyzed how well classification based on sound-evoked activity patterns of neuronal populations replicates the original stimulus categories. Of the three regions, the rostral region (rR), which included core area R and medial belt area RM, yielded the greatest classification success across all stimulus classes or between classes of natural sounds. Starting from ∼80 ms past stimulus onset, clustering based on the population response in rR became clearly more successful than clustering based on responses from any other region. Our study demonstrates that specialization for sound-identity processing can be found very early in the auditory ventral stream. Furthermore, the fact that this processing develops over time can shed light on underlying mechanisms. Finally, we show that population analysis is a more sensitive method for revealing functional specialization than conventional types of analysis.

scholarly journals Reading problems and their connection with visual search and attention: The search for a cause continues

2021 ◽  
Author(s):  
Heida Maria Sigurdardottir ◽  
Hilma Ros Omarsdóttir ◽  
Anna Sigridur Valgeirsdottir
Keyword(s):  
Visual Search ◽  
Internal Control ◽  
Search Task ◽  
Conjunction Search ◽  
Reading Problems ◽  
Visual Stream ◽  
Attentional Processes ◽  
Search Tasks ◽  
Reading Abilities ◽  
Gating Mechanism

Attention has been hypothesized to act as a sequential gating mechanism for the orderly processing of letters in words. These same visuo-attentional processes are assumed to partake in some but not all visual search tasks. In the current study, 60 adults with varying degrees of reading abilities, ranging from expert readers to severely impaired dyslexic readers, completed an attentionally demanding visual conjunction search task thought to heavily rely on the dorsal visual stream. A visual feature search task served as an internal control. According to the dorsal view of dyslexia, reading problems should go hand in hand with specific problems in visual conjunction search – particularly elevated conjunction search slopes (time per search item) – which would be interpreted as a problem with visual attention. Results showed that reading problems were associated with slower visual search, especially conjunction search. However, problems with reading were not associated with increased conjunction search slopes but instead with increased conjunction search intercepts, traditionally not interpreted as reflecting attentional processes. Our data are hard to reconcile with hypothesized problems in dyslexia with the serial moving of an attentional spotlight across a visual scene or a page of text.

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