title: Neural selectivity and representation of gloss in the monkey inferior temporal cortex.
abstract: When we view an object, its appearance depends in large part on specific surface reflectance properties; among these is surface gloss, which provides important information about the material composition of the object and the fine structure of its surface. To study how gloss is represented in the visual cortical areas related to object recognition, we examined the responses of neurons in the inferior temporal (IT) cortex of the macaque monkey to a set of object images exhibiting various combinations of specular reflection, diffuse reflection, and roughness, which are important physical parameters of surface gloss. We found that there are neurons in the lower bank of the superior temporal sulcus that selectively respond to specific gloss. This neuronal selectivity was largely maintained when the shape or illumination of the object was modified and perceived glossiness was unchanged. By contrast, neural responses were significantly altered when the pixels of the images were randomly rearranged, and perceived glossiness was dramatically changed. The stimulus preference of these neurons differed from cell to cell, and, as a population, they systematically represented a variety of surface glosses. We conclude that, within the visual cortex, there are mechanisms operating to integrate local image features and extract information about surface gloss and that this information is systematically represented in the IT cortex, an area playing an important role in object recognition.
authors.affiliation: Division of Sensory and Cognitive Information, National Institute for Physiological Sciences, The Graduate University for Advanced Studies (Sokendai), Okazaki 444-8585, Aichi, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Nishio
authors.forename: Naokazu
authors.initials: N
authors.lastname: Goda
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Komatsu
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001931:Brain Mapping; D005260:Female; D005556:Form Perception / Q000502:physiology*; D007839:Functional Laterality; D007091:Image Processing, Computer-Assisted; D008029:Lighting; D008252:Macaca fascicularis / Q000033:anatomy & histology / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance; D013702:Temporal Lobe / Q000166:cytology* / Q000502:physiology