scholarly journals Curvature domains in V4 of macaque monkey

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jia Ming Hu ◽  
Xue Mei Song ◽  
Qiannan Wang ◽  
Anna Wang Roe
Keyword(s):  
Shape Representation ◽  
Large Body ◽  
Macaque Monkey ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Intrinsic Signal ◽  
Area V4 ◽  
Complex Orientation ◽  
Complex Shapes ◽  
Complex Curvature

An important aspect of visual object recognition is the ability to perceive object shape. Two basic components of complex shapes are straight and curved contours. A large body of evidence suggests a modular hierarchy for shape representation progressing from simple and complex orientation in early areas V1 and V2, to increasingly complex stages of curvature representation in V4, TEO, and TE. Here, we reinforce and extend the concept of modular representation. Using intrinsic signal optical imaging in Macaque area V4, we find sub-millimeter sized modules for curvature representation that are organized from low to high curvatures as well as domains with complex curvature preference. We propose a possible ‘curvature hypercolumn’ within V4. In combination with previous studies, we suggest that the key emergent functions at each stage of cortical processing are represented in systematic, modular maps.

scholarly journals Curvature-processing domains in primate V4

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Rendong Tang ◽  
Qianling Song ◽  
Ying Li ◽  
Rui Zhang ◽  
Xingya Cai ◽  
...  
Keyword(s):  
Calcium Imaging ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Intrinsic Signal ◽  
Two Photon ◽  
Contour Shape ◽  
Wide Range ◽  
Shape Tuning ◽  
Common Shape

Neurons in primate V4 exhibit various types of selectivity for contour shapes, including curves, angles, and simple shapes. How are these neurons organized in V4 remains unclear. Using intrinsic signal optical imaging and two-photon calcium imaging, we observed submillimeter functional domains in V4 that contained neurons preferring curved contours over rectilinear ones. These curvature domains had similar sizes and response amplitudes as orientation domains but tended to separate from these regions. Within the curvature domains, neurons that preferred circles or curve orientations clustered further into finer scale subdomains. Nevertheless, individual neurons also had a wide range of contour selectivity, and neighboring neurons exhibited a substantial diversity in shape tuning besides their common shape preferences. In strong contrast to V4, V1 and V2 did not have such contour-shape-related domains. These findings highlight the importance and complexity of curvature processing in visual object recognition and the key functional role of V4 in this process.

Temporal dynamics of 2D and 3D shape representation in macaque visual area V4

2006 ◽  
Vol 23 (5) ◽  
pp. 749-763 ◽  
Author(s):  
JAY HEGDÉ ◽  
DAVID C. VAN ESSEN
Keyword(s):  
Temporal Dynamics ◽  
Shape Representation ◽  
Macaque Monkey ◽  
Large Stimulus ◽  
3D Shape ◽  
Area V4 ◽  
Single Animal ◽  
Distributed Process ◽  
V4 Neurons ◽  
2D And 3D

We studied the temporal dynamics of shape representation in area V4 of the alert macaque monkey. Analyses were based on two large stimulus sets, one equivalent to the 2D shape stimuli used in a previous study of V2, and the other a set of stereoscopic 3D shape stimuli. As in V2, we found that information conveyed by individual V4 neurons about the stimuli tended to be maximal during the initial transient response and generally lower, albeit statistically significant, afterwards. The population response was substantially correlated from one stimulus to the next during the transients, and decorrelated as responses decayed. V4 responses showed significantly longer latencies than in V2, especially for the 3D stimulus set. Recordings from area V1 in a single animal revealed temporal dynamic patterns in response to the 2D shape stimuli that were largely similar to those in V2 and V4. Together with earlier results, these findings provide evidence for a distributed process of coarse-to-fine representation of shape stimuli in the visual cortex.

scholarly journals Curvature domains in V4 of Macaque Monkey

2020 ◽  
Author(s):  
Jiaming Hu ◽  
Xue Mei Song ◽  
Qiannan Wang ◽  
Anna Wang Roe
Keyword(s):  
Visual Cortex ◽  
Optical Imaging ◽  
Functional Organization ◽  
Macaque Monkey ◽  
Visual Object ◽  
Shape Information ◽  
Object Shape ◽  
Area V4 ◽  
Monkey Visual Cortex ◽  
Visual Cortical

AbstractAn important aspect of visual object recognition is the ability to perceive object shape. How the brain encodes fundamental aspects of shape information remains poorly understood. Models of object shape representation describe a multi-stage process that includes encoding of contour orientation and curvature. While modules encoding contour orientation are well established (orientation domains in V1 and V2 visual cortical areas), whether there are modules for curvature is unknown. In this study, we identify a module for curvature representation in area V4 of monkey visual cortex and illustrate a systematic representation of low to high curvature and of curvature orientation, indicative of curvature hypercolumns in V4. We suggest that identifying systematic modular organizations at each stage of the visual cortical hierarchy signifies the key computations performed.SignificanceWe use intrinsic signal optical imaging in area V4 of anesthetized macaque monkey to study the functional organization of curvature representation. We find a modular basis for cue-invariant curvature representation in area V4 of monkey visual cortex and illustrate a systematic representation from low to high curvature and of curvature orientation, replete with curvature pinwheels. This is the first report of systematic functional organization for curvature representation in the visual system. The use of optical imaging has revealed at a population level spatial details of cortical responses, something which has not been evident from previous studies of single neurons. These data support a representational architecture underlying a ‘curvature hypercolumn’ in V4.

scholarly journals Posterior inferotemporal cortex cells use multiple visual pathways to complement fine and coarse discriminations

2016 ◽  
Author(s):  
C. R. Ponce ◽  
S. G. Lomber ◽  
M. S. Livingstone
Keyword(s):  
Visual Recognition ◽  
Temporal Cortex ◽  
Macaque Monkey ◽  
Inferior Temporal Cortex ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Visual Areas ◽  
Cortical Cooling ◽  
Feature Selectivity ◽  
Pit Cells

ABSTRACTIn the macaque monkey brain, posterior inferior temporal cortex (PIT) cells are responsible for visual object recognition. They receive concurrent inputs from visual areas V4, V3 and V2. We asked how these different anatomical pathways contribute to PIT response properties by deactivating them while monitoring PIT activity. Using cortical cooling of areas V2/V3 or V4 and a hierarchical model of visual recognition, we conclude that these distinct pathways do not transmit different classes of visual features, but serve instead to maintain a balance of local-and global-feature selectivity in IT.

Developmental Trajectory of Visual Object Recognition Revealed by fMRI

2007 ◽  
Author(s):  
K. Suzanne Scherf ◽  
Marlene Behrmann ◽  
Kate Humphreys ◽  
Beatriz Luna
Keyword(s):  
Object Recognition ◽  
Developmental Trajectory ◽  
Visual Object ◽  
Visual Object Recognition

scholarly journals Q -ball imaging of macaque white matter architecture

2005 ◽  
Vol 360 (1457) ◽  
pp. 869-879 ◽  
Author(s):  
David S Tuch ◽  
Jonathan J Wisco ◽  
Mark H Khachaturian ◽  
Leeland B Ekstrom ◽  
Rolf Kötter ◽  
...  
Keyword(s):  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Imaging ◽  
Large Body ◽  
Macaque Monkey ◽  
High Angular Resolution ◽  
Imaging Method ◽  
Diffusion Tractography ◽  
Axonal Projections ◽  
Histological Validation

Diffusion-weighted magnetic resonance imaging holds substantial promise as a technique for non-invasive imaging of white matter (WM) axonal projections. For diffusion imaging to be capable of providing new insight into the connectional neuroanatomy of the human brain, it will be necessary to histologically validate the technique against established tracer methods such as horseradish peroxidase and biocytin histochemistry. The macaque monkey provides an ideal model for histological validation of the diffusion imaging method due to the phylogenetic proximity between humans and macaques, the gyrencephalic structure of the macaque cortex, the large body of knowledge on the neuroanatomic connectivity of the macaque brain and the ability to use comparable magnetic resonance acquisition protocols in both species. Recently, it has been shown that high angular resolution diffusion imaging (HARDI) can resolve multiple axon orientations within an individual imaging voxel in human WM. This capability promises to boost the accuracy of tract reconstructions from diffusion imaging. If the macaque is to serve as a model for histological validation of the diffusion tractography method, it will be necessary to show that HARDI can also resolve intravoxel architecture in macaque WM. The present study therefore sought to test whether the technique can resolve intravoxel structure in macaque WM. Using a HARDI method called q -ball imaging (QBI) it was possible to resolve composite intravoxel architecture in a number of anatomic regions. QBI resolved intravoxel structure in, for example, the dorsolateral convexity, the pontine decussation, the pulvinar and temporal subcortical WM. The paper concludes by reviewing remaining challenges for the diffusion tractography project.

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