Preserved Expert Object Recognition in a Case of Visual Hemiagnosia

We examined a stroke patient (HWS) with a unilateral lesion of the right medial ventral visual stream, involving the right fusiform and parahippocampal gyri. In a number of object recognition tests with lateralized presentations of target stimuli, HWS showed significant symptoms of hemiagnosia with contralesional recognition deficits for everyday objects. We further explored the patient's capacities of visual expertise that were acquired before the current perceptual impairment became effective. We confronted him with objects he was an expert for already before stroke onset and compared this performance with the recognition of familiar everyday objects. HWS was able to identify significantly more of the specific (“expert”) than of the everyday objects on the affected contralesional side. This observation of better expert object recognition in visual hemiagnosia allows for several interpretations. The results may be caused by enhanced information processing for expert objects in the ventral system in the affected or the intact hemisphere. Expert knowledge could trigger top–down mechanisms supporting object recognition despite of impaired basic functions of object processing. More importantly, the current work demonstrates that top–down mechanisms of visual expertise influence object recognition at an early stage, probably before visual object information propagates to modules of higher object recognition. Because HWS showed a lesion to the fusiform gyrus and spared capacities of expert object recognition, the current study emphasizes possible contributions of areas outside the ventral stream to visual expertise.

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

10.1101/2021.07.07.451407 ◽

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.

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Exploring Cortical Attentional System by Using fMRI during a Continuous Perfomance Test

Computational Intelligence and Neuroscience ◽

10.1155/2010/329213 ◽

2010 ◽

Vol 2010 ◽

pp. 1-6 ◽

Cited By ~ 31

Author(s):

M. G. Tana ◽

E. Montin ◽

S. Cerutti ◽

A. M. Bianchi

Keyword(s):

Performance Test ◽

Continuous Performance Test ◽

Blood Oxygen Level Dependent ◽

Brain Regions ◽

Brain Network ◽

Anterior Cingulate ◽

Visual Object ◽

Bold Response ◽

Object Processing ◽

The Right

Functional magnetic resonance imaging (fMRI) was performed in eight healthy subjects to identify the localization, magnitude, and volume extent of activation in brain regions that are involved in blood oxygen level-dependent (BOLD) response during the performance of Conners' Continuous Performance Test (CPT). An extensive brain network was activated during the task including frontal, temporal, and occipital cortical areas and left cerebellum. The more activated cluster in terms of volume extent and magnitude was located in the right anterior cingulate cortex (ACC). Analyzing the dynamic trend of the activation in the identified areas during the entire duration of the sustained attention test, we found a progressive decreasing of BOLD response probably due to a habituation effect without any deterioration of the performances. The observed brain network is consistent with existing models of visual object processing and attentional control and may serve as a basis for fMRI studies in clinical populations with neuropsychological deficits in Conners' CPT performance.

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Chapter 1 Top-down facilitation of visual object recognition: object-based and context-based contributions

Progress in Brain Research - Visual Perception - Fundamentals of Awareness: Multi-Sensory Integration and High-Order Perception ◽

10.1016/s0079-6123(06)55001-0 ◽

2006 ◽

pp. 3-21 ◽

Cited By ~ 104

Author(s):

Mark J. Fenske ◽

Elissa Aminoff ◽

Nurit Gronau ◽

Moshe Bar

Keyword(s):

Object Recognition ◽

Visual Object ◽

Visual Object Recognition ◽

Top Down ◽

Object Based

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Age-Related Changes in the Neural Dynamics of Bottom-Up and Top-Down Processing During Visual Object Recognition: An Electrophysiological Investigation

10.1101/608240 ◽

2019 ◽

Author(s):

Leslie Y. Lai ◽

Romy Frömer ◽

Elena K. Festa ◽

William C. Heindel

Keyword(s):

Object Recognition ◽

Visual Processing ◽

Semantic Integration ◽

Object Identification ◽

Neural Dynamics ◽

Visual Object ◽

Elderly Adults ◽

Top Down ◽

Bottom Up ◽

Increased Sensitivity

ABSTRACTWhen recognizing objects in our environments, we rely on both what we see and what we know. While elderly adults have been found to display increased sensitivity to top-down influences of contextual information during object recognition, the locus of this increased sensitivity remains unresolved. To address this issue, we examined the effects of aging on the neural dynamics of bottom-up and top-down visual processing during rapid object recognition. Specific EEG ERP components indexing bottom-up and top-down processes along the visual processing stream were assessed while systematically manipulating the degree of object ambiguity and scene context congruity. An increase in early attentional feedback mechanisms (as indexed by N1) as well as a functional reallocation of executive attentional resources (as indexed by P200) prior to object identification were observed in elderly adults, while post-perceptual semantic integration (as indexed by N400) remained intact. These findings suggest that compromised bottom-up perceptual processing of visual input in healthy aging leads to an increased involvement of top-down processes to resolve greater perceptual ambiguity during object recognition.

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

10.1101/036475 ◽

2016 ◽

Cited By ~ 8

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.

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Two Categorical Stages of Object Recognition

Perception ◽

10.1068/p070695 ◽

1978 ◽

Vol 7 (6) ◽

pp. 695-705 ◽

Cited By ~ 254

Author(s):

Elizabeth K Warrington ◽

Angela M Taylor

Keyword(s):

Object Recognition ◽

Left Hemisphere ◽

Right Hemisphere ◽

Visual Object ◽

Visual Object Recognition ◽

Perceptual Categorization ◽

Categorization Task ◽

Semantic Categorization ◽

Tentative Model ◽

The Right

Visual object recognition was investigated in a group of eighty-one patients with right- or left-hemisphere lesions. Two tasks were used, one maximizing perceptual categorization by physical identity, the other maximizing semantic categorization by functional identity. The right-hemisphere group showed impairment on the perceptual categorization task and the left-hemisphere group were impaired on the semantic categorization task. The findings are discussed in terms of categorical stages of object recognition. A tentative model of their cerebral organization is suggested.

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The Evolution of Meaning: Spatio-temporal Dynamics of Visual Object Recognition

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2010.21544 ◽

2011 ◽

Vol 23 (8) ◽

pp. 1887-1899 ◽

Cited By ~ 62

Author(s):

Alex Clarke ◽

Kirsten I. Taylor ◽

Lorraine K. Tyler

Keyword(s):

Object Recognition ◽

Semantic Information ◽

Phase Synchronization ◽

Temporal Dynamics ◽

Semantic Integration ◽

Visual Object ◽

Visual Object Recognition ◽

Object Processing ◽

Spatio Temporal ◽

Time Courses

Research on the spatio-temporal dynamics of visual object recognition suggests a recurrent, interactive model whereby an initial feedforward sweep through the ventral stream to prefrontal cortex is followed by recurrent interactions. However, critical questions remain regarding the factors that mediate the degree of recurrent interactions necessary for meaningful object recognition. The novel prediction we test here is that recurrent interactivity is driven by increasing semantic integration demands as defined by the complexity of semantic information required by the task and driven by the stimuli. To test this prediction, we recorded magnetoencephalography data while participants named living and nonliving objects during two naming tasks. We found that the spatio-temporal dynamics of neural activity were modulated by the level of semantic integration required. Specifically, source reconstructed time courses and phase synchronization measures showed increased recurrent interactions as a function of semantic integration demands. These findings demonstrate that the cortical dynamics of object processing are modulated by the complexity of semantic information required from the visual input.

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