Shape Tuning in Macaque Inferior Temporal Cortex

Kayaert, Greet; Biederman, Irving; Vogels, Rufin

doi:10.1523/jneurosci.23-07-03016.2003

Cited by 114 publications

(120 citation statements)

References 41 publications

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“…The differences between V3 and LOC are consistent with the notion that shape processing progresses from orientation specific representations in V3 (high sensitivity for the orientation of the global shape envelope) (Fig. 10) to more orientationindependent representations in LOC (high sensitivity for shape features that might be helpful to achieve viewpoint independence) (Kayaert et al, 2003).…”

Section: The Hierarchical Processing Of Shape In Visual Cortexsupporting

confidence: 82%

Perceived Shape Similarity among Unfamiliar Objects and the Organization of the Human Object Vision Pathway

Beeck

Torfs²,

Wagemans³

2008

J. Neurosci.

254

195

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Humans rely heavily on shape similarity among objects for object categorization and identification. Studies using functional magnetic resonance imaging (fMRI) have shown that a large region in human occipitotemporal cortex processes the shape of meaningful as well as unfamiliar objects. Here, we investigate whether the functional organization of this region as measured with fMRI is related to perceived shape similarity. We found that unfamiliar object classes that are rated as having a similar shape were associated with a very similar response pattern distributed across object-selective cortex, whereas object classes that were rated as being very different in shape were associated with a more different response pattern. Human observers, as well as object-selective cortex, were very sensitive to differences in shape features of the objects such as straight versus curved versus "spiky" edges, more so than to differences in overall shape envelope. Response patterns in retinotopic areas V1, V2, and V4 were not found to be related to perceived shape. The functional organization in area V3 was partially related to perceived shape but without a stronger sensitivity for shape features relative to overall shape envelope. Thus, for unfamiliar objects, the organization of human object-selective cortex is strongly related to perceived shape, and this shape-based organization emerges gradually throughout the object vision pathway.

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Section: The Hierarchical Processing Of Shape In Visual Cortexsupporting

confidence: 82%

Perceived Shape Similarity among Unfamiliar Objects and the Organization of the Human Object Vision Pathway

Beeck

Torfs²,

Wagemans³

2008

J. Neurosci.

254

195

View full text Add to dashboard Cite

show abstract

“…Furthermore, it has been shown that single cells and columns in the monkey IT cortex are selective for moderately complex features 96,97 ; that neurons in v4 and in the posterior IT cortex are tuned for simple shape characteristics 98,99 ; and that IT neurons exhibit gradual tuning in simple shape spaces 50,51 . Finally, single-cell recordings and fMRI studies have provided evidence of selectivity for object parts and non-accidental properties (for example, symmetry, parallelism and collinearity) in the ventral temporal cortex 49,100 , as predicted by structural description theories of object recognition 101,102 .…”

Section: Basic Properties In the Ventral Visual Cortexmentioning

confidence: 94%

“…In a recent study in which monkeys were shown images of objects from many natural categories, the population of IT neurons was highly selective for category membership, especially for animate objects like faces and bodies 48 . More indirect evidence for category selectivity is the observation that single IT neurons are more selective for shape features that are useful for object categorization ('non-accidental properties') than for other shape features ('metric properties') 49 . Thus, the stimulus property that seems to be associated with the strongest selectivity in single cells in the IT cortex is object category.…”

Section: Monkey Studiesmentioning

confidence: 99%

Interpreting fMRI data: maps, modules and dimensions

2008

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Neuroimaging research over the past decade has revealed a detailed picture of the functional organization of the human brain. Here we focus on two fundamental questions that are raised by the detailed mapping of sensory and cognitive functions and illustrate these questions with findings from the object-vision pathway. First, are functionally specific regions that are located close together best understood as distinct cortical modules or as parts of a larger-scale cortical map? Second, what functional properties define each cortical map or module? We propose a model in which overlapping continuous maps of simple features give rise to discrete modules that are selective for complex stimuli.Advances in brain imaging technology (especially functional MRI (fMRI)) have radically improved our understanding of the functional organization of the human brain (BOX 1). In this Review we describe the organization of the ventral visual pathway, which is characterized by strong selectivity for particular object categories (for example, faces and bodies) at the level of both individual neurons and larger cortical regions. We then consider two central questions: whether this organization reflects maps or modules, and what properties are mapped. In each case we derive clues from the literature on the primary sensory cortex, in which cortical maps have been studied extensively using electrophysiology in animals. We find that apparently modular cortical regions, such as orientation columns and face-selective regions, might be parts of larger maps, and show that it is a substantial challenge to determine the basic properties and dimensions that describe functional organization most parsimoniously. We then propose a new framework that reconciles the existence of graded cortical maps and distinct functional modules. In this framework, the strong category selectivity that exists for faces and other objects might arise from the nonlinear combination of multiple correlated maps for simpler stimulus properties. The ventral visual pathwayThe ventral visual pathway comprises a large cortical region that occupies the ventral and lateral surfaces of the occipital and temporal lobes (FIG. 1). A substantial proportion of fMRI voxels in this pathway are 'object-selective' -that is, they respond more strongly when people view images of objects than when people view scrambled versions of these objects or texture patterns. This object-selective region is often referred to as the lateral occipital complex (LOC) 1 . The LOC has little selectivity for particular stimulus categories 2-4 , but several regions of NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript cortex near the LOC are selective for particular object categories: they respond at least twice as strongly to their 'preferred' stimuli than to other stimuli. For example, in essentially all humans cortical regions can be found that respond selectively to faces (the fusiform face area (FFA) 5,6 and, in many individuals, the occipital face area (OFA)) 7,8 , to pl...

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“…First, we applied Gaussian filtering to these pictures (full width at half maximum: 35 x 35 pixels, picture size: 600 x 600 pixels, pixel values between 0-255 (8 bit)) (Kayaert et al (2003)). Next, the Euclidean distance was calculated between each pair of pictures, yielding a perceptual dissimilarity matrix.…”

Section: Volumes Of Interestmentioning

confidence: 99%

“…To estimate low-level perceptual similarities between the picture stimuli, Euclidean distances were calculated in the same manner as in the main experiment (Kayaert et al, 2003). Average Euclidean distance between exemplars of a same entity was lower than between different entities (P<.001).…”

Section: Exemplars Experimentsmentioning

confidence: 99%

Right fusiform response patterns reflect visual object identity rather than semantic similarity

Bruffaerts¹,

Dupont²,

Grauwe³

et al. 2013

NeuroImage

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This is a pre-copy-editing, author-produced PDF of an article accepted for publication in NeuroImage following peer review. The definitive publisher-authenticated version (Bruffaerts, R., Dupont, P., De Grauwe, S., Peeters, R., De Deyne, S., Storms, G., and Vandenberghe, R. (2013). Right fusiform response patterns reflect visual object identity rather than semantic similarity, 83: 8797) is available online at: http://dx.doi.org/10. 1016/j.neuroimage.2013.05.128. Bruffaerts et al. (2013 Abstract We previously reported the neuropsychological consequences of a lesion confined to the middle and posterior part of the right fusiform gyrus (case JA) causing a partial loss of knowledge of visual attributes of concrete entities in the absence of category-selectivity (animate versus inanimate). We interpreted this in the context of a two-step model that distinguishes structural description knowledge from associative-semantic processing and implicated the lesioned area in the former process. To test this hypothesis in the intact brain, multi-voxel pattern analysis was used in a series of event-related fMRI studies in a total of 46 healthy subjects. We predicted that activity patterns in this region would be determined by the identity of rather than the conceptual similarity between concrete entities. In a prior behavioral experiment features were generated for each entity by more than 1000 subjects. Based on a hierarchical clustering analysis the entities were organized into 3 semantic clusters (musical instruments, vehicles, tools). Entities were presented as words or pictures. With foveal presentation of pictures, cosine similarity between fMRI response patterns in right fusiform cortex appeared to reflect both the identity of and the semantic similarity between the entities. No such effects were found for words in this region. The effect of object identity was invariant for location, scaling, orientation axis and color (grayscale versus color). It also persisted for different exemplars referring to a same concrete entity. The apparent semantic similarity effect however was not invariant. This study provides further support for a neurobiological distinction between structural description knowledge and processing of semantic relationships and confirms the role of right mid-posterior fusiform cortex in the former process, in accordance with previous lesion evidence.

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Shape Tuning in Macaque Inferior Temporal Cortex

Cited by 114 publications

References 41 publications

Perceived Shape Similarity among Unfamiliar Objects and the Organization of the Human Object Vision Pathway

Perceived Shape Similarity among Unfamiliar Objects and the Organization of the Human Object Vision Pathway

Interpreting fMRI data: maps, modules and dimensions

Right fusiform response patterns reflect visual object identity rather than semantic similarity

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