High-Level Visual Object Representations Are Constrained by Position

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 20; no. 12; pp. 2916 - 2925
• Main Authors: Kravitz, Dwight J., Kriegeskorte, Nikolaus, Baker, Chris I.
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.12.2010
• Subjects: behavior; Brain Mapping; fMRI; Humans; Macaca; Magnetic Resonance Imaging; object recognition; Photic Stimulation; position invariance; vision; Visual Cortex - physiology; Visual Perception - physiology
• ISSN: 1047-3211; 1460-2199
• DOI: 10.1093/cercor/bhq042

It is widely assumed that high-level visual object representations are position-independent (or invariant). While there is sensitivity to position in high-level object-selective cortex, position and object identity are thought to be encoded independently in the population response such that position information is available across objects and object information is available across positions. Contrary to this view, we show, with both behavior and neuroimaging, that visual object representations are position-dependent (tied to limited portions of the visual field). Behaviorally, we show that the effect of priming an object was greatly reduced with any change in position (within- or between-hemifields), indicating nonoverlapping representations of the same object across different positions. Furthermore, using neuroimaging, we show that object-selective cortex is not only highly sensitive to object position but also the ability to differentiate objects based on its response is greatly reduced across different positions, consistent with the observed behavior and the receptive field properties observed in macaque object-selective neurons. Thus, even at the population level, the object information available in response of object-selective cortex is constrained by position. We conclude that even high-level visual object representations are position-dependent.