scholarly journals A step toward understanding the human ventral visual pathway

2017 ◽  
Vol 117 (3) ◽  
pp. 872-875 ◽  
Author(s):  
Erin Goddard
Keyword(s):  
Temporal Cortex ◽  
Visual Pathway ◽  
Higher Order ◽  
Inferior Temporal Cortex ◽  
Cortical Region ◽  
Functional Responses ◽  
Form Processing ◽  
Ventral Visual Pathway ◽  
New Evidence ◽  
Organizational Principles

The human ventral visual pathway is implicated in higher order form processing, but the organizational principles within this region are not yet well understood. Recently, Lafer-Sousa, Conway, and Kanwisher ( J Neurosci 36: 1682–1697, 2016) used functional magnetic resonance imaging to demonstrate that functional responses in the human ventral visual pathway share a broad homology with the those in macaque inferior temporal cortex, providing new evidence supporting the validity of the macaque as a model of the human visual system in this region. In addition, these results give new clues for understanding the organizational principles within the ventral visual pathway and the processing of higher order color and form, suggesting new avenues for research into this cortical region.

Disparity-Selective Neurons in Area V4 of Macaque Monkeys

2002 ◽  
Vol 87 (4) ◽  
pp. 1960-1973 ◽  
Author(s):  
Masayuki Watanabe ◽  
Hiroki Tanaka ◽  
Takanori Uka ◽  
Ichiro Fujita
Keyword(s):  
Receptive Field ◽  
Binocular Disparity ◽  
Temporal Cortex ◽  
Intermediate Stage ◽  
Visual Pathway ◽  
Inferior Temporal Cortex ◽  
Tuning Curves ◽  
Area V4 ◽  
Ventral Visual Pathway ◽  
V4 Neurons

Area V4 is an intermediate stage of the ventral visual pathway providing major input to the final stages in the inferior temporal cortex (IT). This pathway is involved in the processing of shape, color, and texture. IT neurons are also sensitive to horizontal binocular disparity, suggesting that binocular disparity is processed along the ventral visual pathway. In the present study, we examined the processing of binocular disparity information by V4 neurons. We recorded responses of V4 neurons to binocularly disparate stimuli. A population of V4 neurons modified their responses according to changes of stimulus disparity; neither monocular responses nor eye movements could account for this modulation. Disparity-tuning curves were similar for different locations within a neuron's receptive field. Neighboring neurons recorded using a single electrode displayed similar disparity-tuning properties. These findings indicate that a population of V4 neurons is selective for binocular disparity, invariant for the position of the stimulus within the receptive field. The finding that V4 neurons with similar disparity selectivity are clustered suggests the existence of functional modules for disparity processing in V4.

scholarly journals Representation of Color, Form, and their Conjunction across the Human Ventral Visual Pathway

2020 ◽  
Author(s):  
JohnMark Taylor ◽  
Yaoda Xu
Keyword(s):  
Visual Cortex ◽  
Temporal Cortex ◽  
Visual Pathway ◽  
Significant Feature ◽  
Form Processing ◽  
Neuroscience Research ◽  
Ventral Visual Pathway ◽  
Early Visual Cortex ◽  
Form Feature ◽  
Interactive Coding

AbstractDespite decades of neuroscience research, our understanding of the relationship between color and form processing in the primate ventral visual pathway remains incomplete. Using fMRI multivoxel pattern analysis, this study examined the coding of color with both a simple form feature (orientation) and a mid-level form feature (curvature) in human early visual areas V1 to V4, posterior and central color regions, and shape areas in ventral and lateral occipito-temporal cortex. With the exception of the central color region (which showed color but not form decoding), successful color and form decoding was found in all other regions examined, even for color and shape regions showing univariate sensitivity to one feature. That said, all regions exhibited significant feature decoding biases, with decoding from color and shape regions largely consistent with their univariate preferences. Color and form are thus represented in neither a completely distributed nor a completely modular manner, but a biased distributed manner. Interestingly, coding of one feature in a brain region was always tolerant to changes in the other feature, indicating relative independence of color and form coding throughout the ventral visual cortex. Although evidence for interactive coding of color and form also existed, the effect was weak and only existed for color and orientation conjunctions in early visual cortex. No evidence for interactive coding of color and curvature was found. The predominant relationship between color and form coding in the human brain appears to be one of anatomical coexistence (in a biased distributed manner), but representational independence.

Form-From-Motion: MEG Evidence for Time Course and Processing Sequence

2003 ◽  
Vol 15 (2) ◽  
pp. 157-172 ◽  
Author(s):  
M. A. Schoenfeld ◽  
M. Woldorff ◽  
E. Düzel ◽  
H. Scheich ◽  
H.-J. Heinze ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Time Course ◽  
Temporal Cortex ◽  
Occipital Cortex ◽  
Inferior Temporal Cortex ◽  
Cortical Region ◽  
Motion Cues ◽  
Form Analysis ◽  
Msec Delay ◽  
Visual Cortical

The neural mechanisms and role of attention in the processing of visual form defined by luminance or motion cues were studied using magnetoencephalography. Subjects viewed bilateral stimuli composed of moving random dots and were instructed to covertly attend to either left or right hemifield stimuli in order to detect designated target stimuli that required a response. To generate form-from-motion (FFMo) stimuli, a subset of the dots could begin to move coherently to create the appearance of a simple form (e.g., square). In other blocks, to generate form-from-luminance (FFLu) stimuli that served as a control, a gray stimulus was presented superimposed on the randomly moving dots. Neuromagnetic responses were observed to both the FFLu and FFMo stimuli and localized to multiple visual cortical stages of analysis. Early activity in low-level visual cortical areas (striate/early extrastriate) did not differ for FFLu versus FFMo stimuli, nor as a function of spatial attention. Longer latency responses elicited by the FFLu stimuli were localized to the ventral-lateral occipital cortex (LO) and the inferior temporal cortex (IT). The FFMo stimuli also generated activity in the LO and IT, but only after first eliciting activity in the lateral occipital cortical region corresponding to MT/V5, resulting in a 50–60 msec delay in activity. All of these late responses (MT/V5, LO, and IT) were significantly modulated by spatial attention, being greatly attenuated for ignored FFLu and FFMo stimuli. These findings argue that processing of form in IT that is defined by motion requires a serial processing of information, first in the motion analysis pathway from V1 to MT/V5 and thereafter via the form analysis stream in the ventral visual pathway to IT.

scholarly journals The Organization and Operation of Inferior Temporal Cortex

2018 ◽  
Vol 4 (1) ◽  
pp. 381-402 ◽  
Author(s):  
Bevil R. Conway
Keyword(s):  
Scene Perception ◽  
Temporal Cortex ◽  
Spatial Relationship ◽  
Inferior Temporal Cortex ◽  
Future Research ◽  
Functional Responses ◽  
Form And Function ◽  
High Acuity ◽  
The Face ◽  
And Function

Inferior temporal cortex (IT) is a key part of the ventral visual pathway implicated in object, face, and scene perception. But how does IT work? Here, I describe an organizational scheme that marries form and function and provides a framework for future research. The scheme consists of a series of stages arranged along the posterior-anterior axis of IT, defined by anatomical connections and functional responses. Each stage comprises a complement of subregions that have a systematic spatial relationship. The organization of each stage is governed by an eccentricity template, and corresponding eccentricity representations across stages are interconnected. Foveal representations take on a role in high-acuity object vision (including face recognition); intermediate representations compute other aspects of object vision such as behavioral valence (using color and surface cues); and peripheral representations encode information about scenes. This multistage, parallel-processing model invokes an innately determined organization refined by visual experience that is consistent with principles of cortical development. The model is also consistent with principles of evolution, which suggest that visual cortex expanded through replication of retinotopic areas. Finally, the model predicts that the most extensively studied network within IT—the face patches—is not unique but rather one manifestation of a canonical set of operations that reveal general principles of how IT works.

scholarly journals The Representation of Objects in the Human Occipital and Temporal Cortex

2000 ◽  
Vol 12 (supplement 2) ◽  
pp. 35-51 ◽  
Author(s):  
Alumit Ishai ◽  
Leslie G. Ungerleider ◽  
Alex Martin ◽  
James V. Haxby
Keyword(s):  
Temporal Cortex ◽  
Occipital Cortex ◽  
Visual Pathway ◽  
Distributed Representation ◽  
National Academy Of Sciences ◽  
Line Drawings ◽  
Ventral Visual Pathway ◽  
Presentation Formats ◽  
Ventral Temporal Cortex ◽  
Object Form

Recently, we identified, using fMRI, three bilateral regions in the ventral temporal cortex that responded preferentially to faces, houses, and chairs [Ishai, A., Ungerleider, L. G., Martin, A., Schouten, J. L., & Haxby, J. Y. (1999). Distributed representation of objects in the human ventral visual pathway. Proceedings of the National Academy of Sciences, U.S.A., 96, 9379-9384]. Here, we report differential patterns of activation, similar to those seen in the ventral temporal cortex, in bilateral regions of the ventral occipital cortex. We also found category-related responses in the dorsal occipital cortex and in the superior temporal sulcus. Moreover, rather than activating discrete, segregated areas, each category was associated with its own differential pattern of response across a broad expanse of cortex. The distributed patterns of response were similar across tasks (passive viewing, delayed matching) and presentation formats (photographs, line drawings). We propose that the representation of objects in the ventral visual pathway, including both occipital and temporal regions, is not restricted to small, highly selective patches of cortex but, instead, is a distributed representation of information about object form. Within this distributed system, the representation of faces appears to be less extensive as compared to the representations of nonface objects.

scholarly journals Visual featural topography in the human ventral visual pathway

2020 ◽  
Author(s):  
Shijia Fan ◽  
Xiaosha Wang ◽  
Xiaoying Wang ◽  
Tao Wei ◽  
Yanchao Bi
Keyword(s):  
Temporal Cortex ◽  
Visual Pathway ◽  
Visual Features ◽  
Natural Image ◽  
Visual Object ◽  
Natural Image Statistics ◽  
Image Statistics ◽  
Object Domain ◽  
Ventral Visual Pathway ◽  
Different Types

AbstractVisual object recognition in humans and nonhuman primates is achieved by the ventral visual pathway (ventral occipital-temporal cortex, VOTC), which shows a well-documented object domain structure. An on-going question has been what type of information is processed in higher-order VOTC that underlies such observations, with recent evidence suggesting effects of certain visual features. Combining computational vision models, fMRI experiment using a parametric-modulation approach, and natural image statistics of common objects, we depicted the neural distribution of a comprehensive set of visual features in VOTC, identifying voxel sensitivities to specific feature sets across geometry/shape, Fourier power, and color. The visual feature combination pattern in VOTC is significantly explained by their relationships to different types of response-action computation (Fight-or-Flight, Navigation, and Manipulation), as derived from behavioral ratings and natural image statistics. These results offer the first comprehensive visual featural map in VOTC and a plausible theoretical explanation as a mapping onto different types of downstream response-action systems.

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