Document Detail

Representation of regular and irregular shapes in macaque inferotemporal cortex.
MedLine Citation:
PMID:  15616128     Owner:  NLM     Status:  MEDLINE    
We determined the degree to which the response modulation of macaque inferior temporal (IT) neurons corresponds to perceptual versus physical shape similarities. IT neurons were tested with four groups of shapes. One group consisted of variations of simple, symmetrical (i.e. regular) shapes that differed in nonaccidental properties (NAPs, i.e. viewpoint-invariant), such as curved versus straight contours. The second and third groups were composed of, respectively, simple and complex asymmetrical (i.e. irregular) shapes, all with curved contours. A fourth group consisted of simple, asymmetrical shapes, but with straight (corners) instead of curved contours. The neural modulations were greater for the shapes differing in NAPs than for the shapes differing in the configuration of the convexities and concavities. Multidimensional scaling showed that a population code of the neural activity could readily distinguish the four shape groups. This pattern of neural modulation was strongly manifested in the results of a sorting task by human subjects but could not be predicted using current image-based models (i.e. pixel energies, V1-like Gabor-jet filtering and HMAX). The representation of shape in IT thus exceeds a mere faithful representation of physical reality, by emphasizing perceptually salient features relevant for essential categorizations.
Greet Kayaert; Irving Biederman; Rufin Vogels
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-12-22
Journal Detail:
Title:  Cerebral cortex (New York, N.Y. : 1991)     Volume:  15     ISSN:  1047-3211     ISO Abbreviation:  Cereb. Cortex     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-08-09     Completed Date:  2005-09-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9110718     Medline TA:  Cereb Cortex     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1308-21     Citation Subset:  IM    
Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Leuven, Belgium.
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MeSH Terms
Discrimination (Psychology) / physiology
Fixation, Ocular
Form Perception / physiology*
Image Processing, Computer-Assisted
Macaca mulatta
Models, Neurological
Photic Stimulation
Size Perception / physiology
Temporal Lobe / cytology,  physiology*

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