The role of binocular disparity in stereoscopic images of objects in the macaque anterior intraparietal area

PLoS One. 2013;8(2):e55340. doi: 10.1371/journal.pone.0055340. Epub 2013 Feb 7.


Neurons in the macaque Anterior Intraparietal area (AIP) encode depth structure in random-dot stimuli defined by gradients of binocular disparity, but the importance of binocular disparity in real-world objects for AIP neurons is unknown. We investigated the effect of binocular disparity on the responses of AIP neurons to images of real-world objects during passive fixation. We presented stereoscopic images of natural and man-made objects in which the disparity information was congruent or incongruent with disparity gradients present in the real-world objects, and images of the same objects where such gradients were absent. Although more than half of the AIP neurons were significantly affected by binocular disparity, the great majority of AIP neurons remained image selective even in the absence of binocular disparity. AIP neurons tended to prefer stimuli in which the depth information derived from binocular disparity was congruent with the depth information signaled by monocular depth cues, indicating that these monocular depth cues have an influence upon AIP neurons. Finally, in contrast to neurons in the inferior temporal cortex, AIP neurons do not represent images of objects in terms of categories such as animate-inanimate, but utilize representations based upon simple shape features including aspect ratio.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Macaca mulatta
  • Male
  • Parietal Lobe / physiology*
  • Vision, Binocular*

Grant support

This work was supported by Fonds voor Wetenschappelijk Onderzoek Vlaanderen (G.0713.09), ERC-StG-260607, Programmafinanciering PFV10/008, Geconcerteerde Onderzoeksacties GOA 10/19, and Interuniversitaire Attractiepolen IUAP P6/29. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.