A Cortical Mechanism for Triggering Top-Down Facilitation in Visual Object Recognition

2003 ◽  
Vol 15 (4) ◽  
pp. 600-609 ◽  
Author(s):  
Moshe Bar
Keyword(s):  
Object Recognition ◽  
Visual Recognition ◽  
Temporal Cortex ◽  
Input Image ◽  
Initial Guess ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Top Down ◽  
Bottom Up ◽  
Level Information

The majority of the research related to visual recognition has so far focused on bottom-up analysis, where the input is processed in a cascade of cortical regions that analyze increasingly complex information. Gradually more studies emphasize the role of top-down facilitation in cortical analysis, but it remains something of a mystery how such processing would be initiated. After all, top-down facilitation implies that high-level information is activated earlier than some relevant lower-level information. Building on previous studies, I propose a specific mechanism for the activation of top-down facilitation during visual object recognition. The gist of this hypothesis is that a partially analyzed version of the input image (i.e., a blurred image) is projected rapidly from early visual areas directly to the prefrontal cortex (PFC). This coarse representation activates in the PFC expectations about the most likely interpretations of the input image, which are then back-projected as an “initial guess” to the temporal cortex to be integrated with the bottom-up analysis. The top-down process facilitates recognition by substantially limiting the number of object representations that need to be considered. Furthermore, such a rapid mechanism may provide critical information when a quick response is necessary.

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

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.

Minimal Recognizable Configurations Elicit Category-selective Responses in Higher Order Visual Cortex

2019 ◽  
Vol 31 (9) ◽  
pp. 1354-1367
Author(s):  
Yael Holzinger ◽  
Shimon Ullman ◽  
Daniel Harari ◽  
Marlene Behrmann ◽  
Galia Avidan
Keyword(s):  
Visual Cortex ◽  
Object Recognition ◽  
Visual Recognition ◽  
Recognition Performance ◽  
Occipital Cortex ◽  
Building Blocks ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Face Area ◽  
Early Visual Cortex

Visual object recognition is performed effortlessly by humans notwithstanding the fact that it requires a series of complex computations, which are, as yet, not well understood. Here, we tested a novel account of the representations used for visual recognition and their neural correlates using fMRI. The rationale is based on previous research showing that a set of representations, termed “minimal recognizable configurations” (MIRCs), which are computationally derived and have unique psychophysical characteristics, serve as the building blocks of object recognition. We contrasted the BOLD responses elicited by MIRC images, derived from different categories (faces, objects, and places), sub-MIRCs, which are visually similar to MIRCs, but, instead, result in poor recognition and scrambled, unrecognizable images. Stimuli were presented in blocks, and participants indicated yes/no recognition for each image. We confirmed that MIRCs elicited higher recognition performance compared to sub-MIRCs for all three categories. Whereas fMRI activation in early visual cortex for both MIRCs and sub-MIRCs of each category did not differ from that elicited by scrambled images, high-level visual regions exhibited overall greater activation for MIRCs compared to sub-MIRCs or scrambled images. Moreover, MIRCs and sub-MIRCs from each category elicited enhanced activation in corresponding category-selective regions including fusiform face area and occipital face area (faces), lateral occipital cortex (objects), and parahippocampal place area and transverse occipital sulcus (places). These findings reveal the psychological and neural relevance of MIRCs and enable us to make progress in developing a more complete account of object recognition.

The Role of Visual Field Position in Object Recognition

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 126-126
Author(s):  
M Dill ◽  
S Edelman
Keyword(s):  
Object Recognition ◽  
Visual Recognition ◽  
Human Subjects ◽  
Visual Object ◽  
Translation Invariance ◽  
Visual Object Recognition ◽  
Theoretical Approaches ◽  
Object Based ◽  
New Locations ◽  
Incomplete Performance

Visual recognition of objects is generally assumed to be independent of the location in the field of view. Experiments have shown, however, that for stimuli such as random-dot clouds recognition can be severely affected by retinal displacement (Foster and Kahn, 1985 Biological Cybernetics51 305 – 312; Nazir and O'Regan, 1990 Spatial Vision5 81 – 100; Dill and Fahle, Perception & Psychophysics in press). In a series of new experiments, we tested whether similar shortcomings of translation invariance can be obtained also with more natural-looking objects. For that purpose, we tested human subjects with 3-D animal-like shapes that had been employed previously in studies of rotation invariance (Edelman, 1995 Biological Cybernetics72 207 – 220). Some of our experiments included same - different discrimination, while in others the subjects had to label the briefly displayed stimulus with one of two possible labels. In both tasks, translation invariance was found to be incomplete: performance was significantly reduced when object memory had to be transferred to new locations. This positional specificity parallels the imperfect generalisation of recognition over rotation in depth, reported in the past years by many research groups. Similar to those findings, our present results suggest that the mechanisms of visual object recognition may be view-based rather than object-based. As before, these results have implications concerning the various theoretical approaches to the understanding of recognition currently under consideration.

Top-Down Facilitation in Visual Object Recognition

2004 ◽  
Author(s):  
Annette M. Schmid ◽  
Marianna D. Eddy ◽  
Phillip J. Holcomb
Keyword(s):  
Object Recognition ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Top Down

Visual Recognition

2005 ◽  
Vol 16 (2) ◽  
pp. 152-160 ◽  
Author(s):  
Kalanit Grill-Spector ◽  
Nancy Kanwisher
Keyword(s):  
Object Recognition ◽  
Exposure Duration ◽  
Visual Recognition ◽  
Natural Images ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Perceptual Categorization ◽  
Identification Task ◽  
Categorization Task ◽  
Processing Steps

What is the sequence of processing steps involved in visual object recognition? We varied the exposure duration of natural images and measured subjects' performance on three different tasks, each designed to tap a different candidate component process of object recognition. For each exposure duration, accuracy was lower and reaction time longer on a within-category identification task (e.g., distinguishing pigeons from other birds) than on a perceptual categorization task (e.g., birds vs. cars). However, strikingly, at each exposure duration, subjects performed just as quickly and accurately on the categorization task as they did on a task requiring only object detection: By the time subjects knew an image contained an object at all, they already knew its category. These findings place powerful constraints on theories of object recognition.

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