Fast binary shape categorization

2018 ◽  
Vol 67 (1) ◽  
pp. 26-41
Author(s):  
Insaf Setitra ◽  
Slimane Larabi
Keyword(s):  
2017 ◽  
Author(s):  
B. Garcin ◽  
M. Urbanski ◽  
M. Thiebaut De Schotten ◽  
R. Levy ◽  
E. Volle

AbstractCategorization is the mental operation by which the brain classifies objects and events. It is classically assessed using semantic and non-semantic matching or sorting tasks. These tasks show a high variability in performance across healthy controls and the cerebral bases supporting this variability remain unknown. In this study we performed a voxel-based morphometry study to explore the relationships between semantic and shape categorization tasks and brain morphometric differences in 50 controls. We found significant correlation between categorization performance and the volume of the grey matter in the right anterior middle and inferior temporal gyri. Semantic categorization tasks were associated with more rostral temporal regions than shape categorization tasks. A significant relationship was also shown between white matter volume in the right temporal lobe and performance in the semantic tasks. Tractography revealed that this white matter region involved several projection and association fibers, including the arcuate fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and inferior longitudinal fasciculus. These results suggest that categorization abilities are supported by the anterior portion of the right temporal lobe and its interaction with other areas.HighlightsAnterior temporal lobe morphometry correlates with categorization performancesSemantic is associated with a more rostral temporal region than shape categorizationSemantic categorization performances are associated with right temporal connections


2013 ◽  
Author(s):  
Linsey Smith ◽  
Micah B. Goldwater ◽  
Bryan Matlen ◽  
Raedy Ping ◽  
Susan Levine ◽  
...  
Keyword(s):  

2013 ◽  
Vol 4 (2) ◽  
pp. 1-16 ◽  
Author(s):  
Hedi Tabia ◽  
Mohamed Daoudi ◽  
Jean-Philippe Vandeborre ◽  
Olivier Colot

Author(s):  
Mohammad Reza Daliri ◽  
Elisabetta Delponte ◽  
Alessandro Verri ◽  
Vincent Torre

2019 ◽  
Author(s):  
Chuan-Peng Hu ◽  
Yuxuan Lan ◽  
Neil Macrae ◽  
Jie Sui

People display systematic priorities to self-related stimuli. As the self is not a unified entity, however, it remains unclear which aspects of the self are crucial to producing this stimulus prioritization. To explore this issue, we manipulated the valence of the self-concept (good me vs. bad me) — a core identity-based facet of the self — using a standard shape-label association task in which participants initially learned the associations (e.g., circle/good-self, triangle/good-other, diamond/bad-self, square/bad-other), after which they completed shape-label matching and shape-categorization tasks, such that attention was directed to different aspects of the stimuli (i.e., self-relevance and valence). The results revealed that responses were more efficient to the good-self shape (vs. other shapes), regardless of the task that was undertaken. A hierarchical drift diffusion model (HDDM) analysis indicated that this good-self prioritization effect was underpinned by differences in the rate of information uptake. These findings demonstrate that activation of the good-self representation exclusively facilitates perceptual decision-making, thereby furthering understanding of the self-prioritization effect.


Author(s):  
Gretchen M. Pavelich ◽  
Kyle R. Brena ◽  
Jared D. Heinze ◽  
Erik Dorf

2018 ◽  
Vol 119 (1) ◽  
pp. 160-176 ◽  
Author(s):  
Hee-kyoung Ko ◽  
Rüdiger von der Heydt

Figure-ground organization in the visual cortex is generally assumed to be based partly on general rules and partly on specific influences of object recognition in higher centers as found in the temporal lobe. To see if shape familiarity influences figure-ground organization, we tested border ownership-selective neurons in monkey V1/V2 with silhouettes of human and monkey face profiles and “nonsense” silhouettes constructed by mirror-reversing the front part of the profile. We found no superiority of face silhouettes compared with nonsense shapes in eliciting border-ownership signals overall. However, in some neurons, border-ownership signals differed strongly between the two categories consistently across many different profile shapes. Surprisingly, this category selectivity appeared as early as 70 ms after stimulus onset, which is earlier than the typical latency of shape-selective responses but compatible with the earliest face-selective responses in the inferior temporal lobe. Although our results provide no evidence for a delayed top-down influence from object recognition centers, they indicate sophisticated shape categorization mechanisms that are much faster than generally assumed. NEW & NOTEWORTHY A long-standing question is whether low-level sensory representations in cortex are influenced by cognitive “top-down” signals. We studied figure-ground organization in the visual cortex by comparing border-ownership signals for face profiles and matched nonsense shapes. We found no sign of “face superiority” in the population border-ownership signal. However, some neurons consistently differentiated between the face and nonsense categories early on, indicating the presence of shape classification mechanisms that are much faster than previously assumed.


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