title: Temporal dynamics of visual category representation in the macaque inferior temporal cortex.
abstract: Object categories are recognized at multiple levels of hierarchical abstractions. Psychophysical studies have shown a more rapid perceptual access to the mid-level category information (e.g., human faces) than the higher (superordinate; e.g., animal) or the lower (subordinate; e.g., face identity) level. Mid-level category members share many features, whereas few features are shared among members of different mid-level categories. To understand better the neural basis of expedited access to mid-level category information, we examined neural responses of the inferior temporal (IT) cortex of macaque monkeys viewing a large number of object images. We found an earlier representation of mid-level categories in the IT population and single-unit responses compared with superordinate- and subordinate-level categories. The short-latency representation of mid-level category information shows that visual cortex first divides the category shape space at its sharpest boundaries, defined by high/low within/between-group similarity. This short-latency, mid-level category boundary map may be a prerequisite for representation of other categories at more global and finer scales.
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Research Center for Brain and Cognitive Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran;
authors.forename: Mohammad-Reza A
authors.initials: MR
authors.lastname: Dehaqani
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Research Center for Brain and Cognitive Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran;
authors.forename: Abdol-Hossein
authors.initials: AH
authors.lastname: Vahabie
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Center for Neural Science, New York University, New York, New York; and.
authors.forename: Roozbeh
authors.initials: R
authors.lastname: Kiani
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Cognitive Systems Lab, Control and Intelligent Processing Centre of Excellence, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran.
authors.forename: Majid Nili
authors.initials: MN
authors.lastname: Ahmadabadi
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Cognitive Systems Lab, Control and Intelligent Processing Centre of Excellence, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran.
authors.forename: Babak Nadjar
authors.initials: BN
authors.lastname: Araabi
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences, Tehran, Iran; Research Center for Brain and Cognitive Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; esteky@ipm.ir.
authors.forename: Hossein
authors.initials: H
authors.lastname: Esteky
mesh_terms: D000818:Animals; D001931:Brain Mapping; D003198:Computer Simulation; D008251:Macaca; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D025341:Principal Component Analysis; D012372:ROC Curve; D011930:Reaction Time; D060388:Support Vector Machine; D013702:Temporal Lobe / Q000166:cytology* / Q000502:physiology; D013997:Time Factors; D014795:Visual Pathways / Q000502:physiology
keywords: category representation; hierarchical abstraction; inferior temporal cortex; object recognition; temporal dynamics